From a721b36e4a3183f4d3a1b7ca46da27b094c6f39e Mon Sep 17 00:00:00 2001 From: Jay Bryant Date: Sat, 14 Dec 2019 10:15:54 -0600 Subject: [PATCH] Editing pass (#1456) I edited for spelling, punctuation, usage, corporate voice, and consistencey. I also added .DS_Store to .gitignore. --- .gitignore | 3 +- docs/src/main/asciidoc/_attributes.adoc | 2 +- .../main/asciidoc/spring-cloud-gateway.adoc | 1346 +++++++++++------ 3 files changed, 885 insertions(+), 466 deletions(-) diff --git a/.gitignore b/.gitignore index 0f4f3fdb..72bc3a95 100644 --- a/.gitignore +++ b/.gitignore @@ -1,3 +1,4 @@ +.DS_Store *~ #* *# @@ -18,4 +19,4 @@ _site/ .shelf *.swp *.swo -.vscode/ \ No newline at end of file +.vscode/ diff --git a/docs/src/main/asciidoc/_attributes.adoc b/docs/src/main/asciidoc/_attributes.adoc index 0ba57ec9..d110bd24 100644 --- a/docs/src/main/asciidoc/_attributes.adoc +++ b/docs/src/main/asciidoc/_attributes.adoc @@ -13,4 +13,4 @@ :sc-ext: java :project-full-name: Spring Cloud Gateway -:all: {asterisk}{asterisk} \ No newline at end of file +:all: {asterisk}{asterisk} diff --git a/docs/src/main/asciidoc/spring-cloud-gateway.adoc b/docs/src/main/asciidoc/spring-cloud-gateway.adoc index 911e94b4..a4561c7a 100644 --- a/docs/src/main/asciidoc/spring-cloud-gateway.adoc +++ b/docs/src/main/asciidoc/spring-cloud-gateway.adoc @@ -8,46 +8,57 @@ include::intro.adoc[] [[gateway-starter]] == How to Include Spring Cloud Gateway -To include Spring Cloud Gateway in your project use the starter with group `org.springframework.cloud` -and artifact id `spring-cloud-starter-gateway`. See the https://projects.spring.io/spring-cloud/[Spring Cloud Project page] -for details on setting up your build system with the current Spring Cloud Release Train. +To include Spring Cloud Gateway in your project, use the starter with a group ID of `org.springframework.cloud` and an artifact ID of `spring-cloud-starter-gateway`. +See the https://projects.spring.io/spring-cloud/[Spring Cloud Project page] for details on setting up your build system with the current Spring Cloud Release Train. -If you include the starter, but, for some reason, you do not want the gateway to be enabled, set `spring.cloud.gateway.enabled=false`. +If you include the starter, but you do not want the gateway to be enabled, set `spring.cloud.gateway.enabled=false`. -IMPORTANT: Spring Cloud Gateway is built upon https://spring.io/projects/spring-boot#learn[Spring Boot 2.x], -https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html[Spring WebFlux], -and https://projectreactor.io/docs[Project Reactor]. As a consequence -many of the familiar synchronous libraries (Spring Data and Spring Security, for example) and patterns you may -not apply when using Spring Cloud Gateway. If you are unfamiliar with these projects we suggest you -begin by reading their documentation to familiarize yourself with some of the new concepts before -working with Spring Cloud Gateway. +IMPORTANT: Spring Cloud Gateway is built on https://spring.io/projects/spring-boot#learn[Spring Boot 2.x], https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html[Spring WebFlux], and https://projectreactor.io/docs[Project Reactor]. +As a consequence, many of the familiar synchronous libraries (Spring Data and Spring Security, for example) and patterns you know may not apply when you use Spring Cloud Gateway. +If you are unfamiliar with these projects, we suggest you begin by reading their documentation to familiarize yourself with some of the new concepts before working with Spring Cloud Gateway. -IMPORTANT: Spring Cloud Gateway requires the Netty runtime provided by Spring Boot and Spring Webflux. It does not work in a traditional Servlet Container or built as a WAR. +IMPORTANT: Spring Cloud Gateway requires the Netty runtime provided by Spring Boot and Spring Webflux. +It does not work in a traditional Servlet Container or when built as a WAR. == Glossary -* *Route*: Route the basic building block of the gateway. It is defined by an ID, a destination URI, a collection of predicates and a collection of filters. A route is matched if aggregate predicate is true. -* *Predicate*: This is a https://docs.oracle.com/javase/8/docs/api/java/util/function/Predicate.html[Java 8 Function Predicate]. The input type is a https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/server/ServerWebExchange.html[Spring Framework `ServerWebExchange`]. This allows developers to match on anything from the HTTP request, such as headers or parameters. -* *Filter*: These are instances https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/server/GatewayFilter.html[Spring Framework `GatewayFilter`] constructed in with a specific factory. Here, requests and responses can be modified before or after sending the downstream request. +* *Route*: The basic building block of the gateway. +It is defined by an ID, a destination URI, a collection of predicates, and a collection of filters. A route is matched if the aggregate predicate is true. +* *Predicate*: This is a https://docs.oracle.com/javase/8/docs/api/java/util/function/Predicate.html[Java 8 Function Predicate]. The input type is a https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/server/ServerWebExchange.html[Spring Framework `ServerWebExchange`]. +This lets you match on anything from the HTTP request, such as headers or parameters. +* *Filter*: These are instances of https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/server/GatewayFilter.html[Spring Framework `GatewayFilter`] that have been constructed with a specific factory. +Here, you can modify requests and responses before or after sending the downstream request. [[gateway-how-it-works]] == How It Works -image::{imagesurl}/spring_cloud_gateway_diagram.png[Spring Cloud Gateway Diagram] +The following diagram provides a high-level overview of how Spring Cloud Gateway works: -Clients make requests to Spring Cloud Gateway. If the Gateway Handler Mapping determines that a request matches a Route, it is sent to the Gateway Web Handler. This handler runs sends the request through a filter chain that is specific to the request. The reason the filters are divided by the dotted line, is that filters may execute logic before the proxy request is sent or after. All "pre" filter logic is executed, then the proxy request is made. After the proxy request is made, the "post" filter logic is executed. +image::spring_cloud_gateway_diagram.png[Spring Cloud Gateway Diagram] -NOTE: URIs defined in routes without a port will get a default port set to 80 and 443 for HTTP and HTTPS URIs respectively. +Clients make requests to Spring Cloud Gateway. If the Gateway Handler Mapping determines that a request matches a route, it is sent to the Gateway Web Handler. +This handler runs the request through a filter chain that is specific to the request. +The reason the filters are divided by the dotted line is that filters can run logic both before and after the proxy request is sent. +All "`pre`" filter logic is executed. Then the proxy request is made. After the proxy request is made, the "`post`" filter logic is run. + +NOTE: URIs defined in routes without a port get default port values of 80 and 443 for the HTTP and HTTPS URIs, respectively. [[gateway-request-predicates-factories]] == Route Predicate Factories -Spring Cloud Gateway matches routes as part of the Spring WebFlux `HandlerMapping` infrastructure. Spring Cloud Gateway includes many built-in Route Predicate Factories. All of these predicates match on different attributes of the HTTP request. Multiple Route Predicate Factories can be combined and are combined via logical `and`. +Spring Cloud Gateway matches routes as part of the Spring WebFlux `HandlerMapping` infrastructure. +Spring Cloud Gateway includes many built-in route predicate factories. +All of these predicates match on different attributes of the HTTP request. +You can combine multiple route predicate factories with logical `and` statements. -=== After Route Predicate Factory -The After Route Predicate Factory takes one parameter, a datetime. This predicate matches requests that happen after the current datetime. +=== The After Route Predicate Factory + +The after route predicate factory takes one parameter, a datetime. +This predicate matches requests that happen after the specified datetime. +The following example configures an after route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -59,13 +70,18 @@ spring: predicates: - After=2017-01-20T17:42:47.789-07:00[America/Denver] ---- +==== -This route matches any request after Jan 20, 2017 17:42 Mountain Time (Denver). +This route matches any request made after Jan 20, 2017 17:42 Mountain Time (Denver). -=== Before Route Predicate Factory -The Before Route Predicate Factory takes one parameter, a datetime. This predicate matches requests that happen before the current datetime. +=== The Before Route Predicate Factory + +The before route predicate factory takes one parameter, a `datetime`. +This predicate matches requests that happen before the specified `datetime`. +The following example configures a before route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -77,13 +93,19 @@ spring: predicates: - Before=2017-01-20T17:42:47.789-07:00[America/Denver] ---- +==== -This route matches any request before Jan 20, 2017 17:42 Mountain Time (Denver). +This route matches any request made before Jan 20, 2017 17:42 Mountain Time (Denver). -=== Between Route Predicate Factory -The Between Route Predicate Factory takes two parameters, datetime1 and datetime2. This predicate matches requests that happen after datetime1 and before datetime2. The datetime2 parameter must be after datetime1. +=== The Between Route Predicate Factory + +The between route predicate factory takes two parameters, `datetime1` and `datetime2`. +This predicate matches requests that happen after `datetime1` and before `datetime2`. +The `datetime2` parameter must be after `datetime1`. +The following example configures a between route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -95,13 +117,19 @@ spring: predicates: - Between=2017-01-20T17:42:47.789-07:00[America/Denver], 2017-01-21T17:42:47.789-07:00[America/Denver] ---- +==== -This route matches any request after Jan 20, 2017 17:42 Mountain Time (Denver) and before Jan 21, 2017 17:42 Mountain Time (Denver). This could be useful for maintenance windows. +This route matches any request made after Jan 20, 2017 17:42 Mountain Time (Denver) and before Jan 21, 2017 17:42 Mountain Time (Denver). +This could be useful for maintenance windows. -=== Cookie Route Predicate Factory -The Cookie Route Predicate Factory takes two parameters, the cookie name and a regular expression. This predicate matches cookies that have the given name and the value matches the regular expression. +=== The Cookie Route Predicate Factory + +The cookie route predicate factory takes two parameters, the cookie name and a regular expression. +This predicate matches cookies that have the given name and whose values match the regular expression. +The following example configures a cookie route predicate factory: .application.yml +==== [source,yaml] ---- spring: @@ -113,13 +141,18 @@ spring: predicates: - Cookie=chocolate, ch.p ---- +==== -This route matches the request has a cookie named `chocolate` who's value matches the `ch.p` regular expression. +This route matches requests that have a cookie named `chocolate` whose value matches the `ch.p` regular expression. -=== Header Route Predicate Factory -The Header Route Predicate Factory takes two parameters, the header name and a regular expression. This predicate matches with a header that has the given name and the value matches the regular expression. +=== The Header Route Predicate Factory + +The header route predicate factory takes two parameters, the header name and a regular expression. +This predicate matches with a header that has the given name whose value matches the regular expression. +The following example configures a header route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -131,13 +164,19 @@ spring: predicates: - Header=X-Request-Id, \d+ ---- +==== -This route matches if the request has a header named `X-Request-Id` whose value matches the `\d+` regular expression (has a value of one or more digits). +This route matches if the request has a header named `X-Request-Id` whose value matches the `\d+` regular expression (that is, it has a value of one or more digits). -=== Host Route Predicate Factory -The Host Route Predicate Factory takes one parameter: a list of host name patterns. The pattern is an Ant style pattern with `.` as the separator. This predicates matches the `Host` header that matches the pattern. +=== The Host Route Predicate Factory + +The host route predicate factory takes one parameter: a list of host name patterns. +The pattern is an Ant-style pattern with `.` as the separator. +This predicates matches the `Host` header that matches the pattern. +The following example configures a host route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -149,18 +188,23 @@ spring: predicates: - Host=**.somehost.org,**.anotherhost.org ---- +==== -URI template variables are supported as well, such as `{sub}.myhost.org`. +URI template variables (such as `{sub}.myhost.org`) are supported as well. -This route would match if the request has a `Host` header has the value `www.somehost.org` or `beta.somehost.org` or `www.anotherhost.org`. +This route matches if the request has a `Host` header with a value of `www.somehost.org` or `beta.somehost.org` or `www.anotherhost.org`. -This predicate extracts the URI template variables (like `sub` defined in the example above) as a map of names and values and places it in the `ServerWebExchange.getAttributes()` with a key defined in `ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE`. Those values are then available for use by <> +This predicate extracts the URI template variables (such as `sub`, defined in the preceding example) as a map of names and values and places it in the `ServerWebExchange.getAttributes()` with a key defined in `ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE`. +Those values are then available for use by <> -=== Method Route Predicate Factory +=== The Method Route Predicate Factory + The Method Route Predicate Factory takes one or more parameters: the HTTP methods to match. +The following example configures a method route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -172,13 +216,17 @@ spring: predicates: - Method=GET,POST ---- +==== -This route would match if the request method was a `GET` or a `POST`. +This route matches if the request method was a `GET` or a `POST`. -=== Path Route Predicate Factory -The Path Route Predicate Factory takes two parameters: a list of Spring `PathMatcher` patterns and an optional flag to `matchOptionalTrailingSeparator`. +=== The Path Route Predicate Factory + +The Path Route Predicate Factory takes two parameters: a list of Spring `PathMatcher` patterns and an optional flag called `matchOptionalTrailingSeparator`. +The following example configures a path route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -188,24 +236,48 @@ spring: - id: host_route uri: https://example.org predicates: - - Path=/foo/{segment},/bar/{segment} + - Path=/red/{segment},/blue/{segment} ---- +==== -This route would match if the request path was, for example: `/foo/1` or `/foo/bar` or `/bar/baz`. +This route matches if the request path was, for example: `/red/1` or `/red/blue` or `/blue/green`. -This predicate extracts the URI template variables (like `segment` defined in the example above) as a map of names and values and places it in the `ServerWebExchange.getAttributes()` with a key defined in `ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE`. Those values are then available for use by <> +This predicate extracts the URI template variables (such as `segment`, defined in the preceding example) as a map of names and values and places it in the `ServerWebExchange.getAttributes()` with a key defined in `ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE`. +Those values are then available for use by <> -A utility method is available to make access to these variables easier. +A utility method (called `get`) is available to make access to these variables easier. +The following example shows how to use the `get` method: +==== [source,java] ---- Map uriVariables = ServerWebExchangeUtils.getPathPredicateVariables(exchange); String segment = uriVariables.get("segment"); ---- +==== -=== Query Route Predicate Factory -The Query Route Predicate Factory takes two parameters: a required `param` and an optional `regexp`. +=== The Query Route Predicate Factory + +The query route predicate factory takes two parameters: a required `param` and an optional `regexp`. +The following example configures a query route predicate: + +.application.yml +==== +[source,yaml] +---- +spring: + cloud: + gateway: + routes: + - id: query_route + uri: https://example.org + predicates: + - Query=green +---- +==== + +The preceding route matches if the request contained a `green` query parameter. .application.yml [source,yaml] @@ -217,31 +289,19 @@ spring: - id: query_route uri: https://example.org predicates: - - Query=baz + - Query=red, gree. ---- -This route would match if the request contained a `baz` query parameter. - -.application.yml -[source,yaml] ----- -spring: - cloud: - gateway: - routes: - - id: query_route - uri: https://example.org - predicates: - - Query=foo, ba. ----- - -This route would match if the request contained a `foo` query parameter whose value matched the `ba.` regexp, so `bar` and `baz` would match. - - -=== RemoteAddr Route Predicate Factory -The RemoteAddr Route Predicate Factory takes a list (min size 1) of CIDR-notation (IPv4 or IPv6) strings, e.g. `192.168.0.1/16` (where `192.168.0.1` is an IP address and `16` is a subnet mask). +The preceding route matches if the request contained a `red` query parameter whose value matched the `gree.` regexp, so `green` and `greet` would match. + + +=== The RemoteAddr Route Predicate Factory + +The RemoteAddr route predicate factory takes a list (min size 1) of CIDR-notation (IPv4 or IPv6) strings, such as `192.168.0.1/16` (where `192.168.0.1` is an IP address and `16` is a subnet mask). +The following example configures a RemoteAddr route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -253,13 +313,17 @@ spring: predicates: - RemoteAddr=192.168.1.1/24 ---- +==== -This route would match if the remote address of the request was, for example, `192.168.1.10`. +This route matches if the remote address of the request was, for example, `192.168.1.10`. -=== Weight Route Predicate Factory -The Weight Route Predicate Factory takes two argument group and weight. The weights are calculated per group. +=== The Weight Route Predicate Factory + +The weight route predicate factory takes two arguments: group and weight. The weights are calculated per group. +The following example configures a weight route predicate: .application.yml +==== [source,yaml] ---- spring: @@ -275,32 +339,37 @@ spring: predicates: - Weight=group1, 2 ---- +==== This route would forward ~80% of traffic to https://weighthigh.org and ~20% of traffic to https://weighlow.org -==== Modifying the way remote addresses are resolved -By default the RemoteAddr Route Predicate Factory uses the remote address from the incoming request. +==== Modifying the Way Remote Addresses Are Resolved + +By default, the RemoteAddr route predicate factory uses the remote address from the incoming request. This may not match the actual client IP address if Spring Cloud Gateway sits behind a proxy layer. You can customize the way that the remote address is resolved by setting a custom `RemoteAddressResolver`. -Spring Cloud Gateway comes with one non-default remote address resolver which is based off of the https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For[X-Forwarded-For header], `XForwardedRemoteAddressResolver`. +Spring Cloud Gateway comes with one non-default remote address resolver that is based off of the https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For[X-Forwarded-For header], `XForwardedRemoteAddressResolver`. -`XForwardedRemoteAddressResolver` has two static constructor methods which take different approaches to security: +`XForwardedRemoteAddressResolver` has two static constructor methods, which take different approaches to security: -`XForwardedRemoteAddressResolver::trustAll` returns a `RemoteAddressResolver` which always takes the first IP address found in the `X-Forwarded-For` header. -This approach is vulnerable to spoofing, as a malicious client could set an initial value for the `X-Forwarded-For` which would be accepted by the resolver. +* `XForwardedRemoteAddressResolver::trustAll` returns a `RemoteAddressResolver` that always takes the first IP address found in the `X-Forwarded-For` header. +This approach is vulnerable to spoofing, as a malicious client could set an initial value for the `X-Forwarded-For`, which would be accepted by the resolver. -`XForwardedRemoteAddressResolver::maxTrustedIndex` takes an index which correlates to the number of trusted infrastructure running in front of Spring Cloud Gateway. -If Spring Cloud Gateway is, for example only accessible via HAProxy, then a value of 1 should be used. +* `XForwardedRemoteAddressResolver::maxTrustedIndex` takes an index that correlates to the number of trusted infrastructure running in front of Spring Cloud Gateway. +If Spring Cloud Gateway is, for example only accessible through HAProxy, then a value of 1 should be used. If two hops of trusted infrastructure are required before Spring Cloud Gateway is accessible, then a value of 2 should be used. -Given the following header value: +Consider the following header value: +==== [source] +---- X-Forwarded-For: 0.0.0.1, 0.0.0.2, 0.0.0.3 +---- +==== - -The `maxTrustedIndex` values below will yield the following remote addresses. +The following `maxTrustedIndex` values yield the following remote addresses: [options="header"] |=== @@ -313,9 +382,10 @@ The `maxTrustedIndex` values below will yield the following remote addresses. |=== [[gateway-route-filters]] -Using Java config: +The following example shows how to achieve the same configuration with Java: -GatewayConfig.java +.GatewayConfig.java +==== [source,java] ---- RemoteAddressResolver resolver = XForwardedRemoteAddressResolver @@ -327,21 +397,27 @@ RemoteAddressResolver resolver = XForwardedRemoteAddressResolver r -> r.remoteAddr("10.1.1.1", "10.10.1.1/24") .uri("https://downstream1") .route("proxied-route", - r -> r.remoteAddr(resolver, "10.10.1.1", "10.10.1.1/24") + r -> r.remoteAddr(resolver, "10.10.1.1", "10.10.1.1/24") .uri("https://downstream2") ) ---- +==== -== GatewayFilter Factories +== `GatewayFilter` Factories -Route filters allow the modification of the incoming HTTP request or outgoing HTTP response in some manner. Route filters are scoped to a particular route. Spring Cloud Gateway includes many built-in GatewayFilter Factories. +Route filters allow the modification of the incoming HTTP request or outgoing HTTP response in some manner. +Route filters are scoped to a particular route. +Spring Cloud Gateway includes many built-in GatewayFilter Factories. -NOTE For more detailed examples on how to use any of the following filters, take a look at the https://github.com/spring-cloud/spring-cloud-gateway/tree/master/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/factory[unit tests]. +NOTE: For more detailed examples of how to use any of the following filters, take a look at the https://github.com/spring-cloud/spring-cloud-gateway/tree/master/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/factory[unit tests]. -=== AddRequestHeader GatewayFilter Factory -The AddRequestHeader GatewayFilter Factory takes a name and value parameter. +=== The `AddRequestHeader` `GatewayFilter` Factory + +The `AddRequestHeader` `GatewayFilter` factory takes a name and value parameter. +The following example configures an `AddRequestHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -351,14 +427,18 @@ spring: - id: add_request_header_route uri: https://example.org filters: - - AddRequestHeader=X-Request-Foo, Bar + - AddRequestHeader=X-Request-red, blue ---- +==== -This will add `X-Request-Foo:Bar` header to the downstream request's headers for all matching requests. +This listing adds `X-Request-red:blue` header to the downstream request's headers for all matching requests. -AddRequestHeader is aware of URI variables used to match a path or host. URI variables may be used in the value and will be expanded at runtime. +`AddRequestHeader` is aware of the URI variables used to match a path or host. +URI variables may be used in the value and are expanded at runtime. +The following example configures an `AddRequestHeader` `GatewayFilter` that uses a variable: .application.yml +==== [source,yaml] ---- spring: @@ -368,15 +448,19 @@ spring: - id: add_request_header_route uri: https://example.org predicates: - - Path=/foo/{segment} + - Path=/red/{segment} filters: - - AddRequestHeader=X-Request-Foo, Bar-{segment} + - AddRequestHeader=X-Request-Red, Blue-{segment} ---- +==== -=== AddRequestParameter GatewayFilter Factory -The AddRequestParameter GatewayFilter Factory takes a name and value parameter. +=== The `AddRequestParameter` `GatewayFilter` Factory + +The `AddRequestParameter` `GatewayFilter` Factory takes a name and value parameter. +The following example configures an `AddRequestParameter` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -386,14 +470,18 @@ spring: - id: add_request_parameter_route uri: https://example.org filters: - - AddRequestParameter=foo, bar + - AddRequestParameter=red, blue ---- +==== -This will add `foo=bar` to the downstream request's query string for all matching requests. +This will add `red=blue` to the downstream request's query string for all matching requests. -AddRequestParameter is aware of URI variables used to match a path or host. URI variables may be used in the value and will be expanded at runtime. +`AddRequestParameter` is aware of the URI variables used to match a path or host. +URI variables may be used in the value and are expanded at runtime. +The following example configures an `AddRequestParameter` `GatewayFilter` that uses a variable: .application.yml +==== [source,yaml] ---- spring: @@ -407,11 +495,15 @@ spring: filters: - AddRequestParameter=foo, bar-{segment} ---- +==== -=== AddResponseHeader GatewayFilter Factory -The AddResponseHeader GatewayFilter Factory takes a name and value parameter. +=== The `AddResponseHeader` `GatewayFilter` Factory + +The `AddResponseHeader` `GatewayFilter` Factory takes a name and value parameter. +The following example configures an `AddResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -421,14 +513,18 @@ spring: - id: add_response_header_route uri: https://example.org filters: - - AddResponseHeader=X-Response-Foo, Bar + - AddResponseHeader=X-Response-Red, Blue ---- +==== -This will add `X-Response-Foo:Bar` header to the downstream response's headers for all matching requests. +This adds `X-Response-Foo:Bar` header to the downstream response's headers for all matching requests. -AddResponseHeader is aware of URI variables used to match a path or host. URI variables may be used in the value and will be expanded at runtime. +`AddResponseHeader` is aware of URI variables used to match a path or host. +URI variables may be used in the value and are expanded at runtime. +The following example configures an `AddResponseHeader` `GatewayFilter` that uses a variable: .application.yml +==== [source,yaml] ---- spring: @@ -442,11 +538,15 @@ spring: filters: - AddResponseHeader=foo, bar-{segment} ---- +==== -=== DedupeResponseHeader GatewayFilter Factory -The DedupeResponseHeader GatewayFilter Factory takes a `name` parameter and an optional `strategy` parameter. `name` can contain a list of header names, space separated. +=== The `DedupeResponseHeader` `GatewayFilter` Factory + +The DedupeResponseHeader GatewayFilter factory takes a `name` parameter and an optional `strategy` parameter. `name` can contain a space-separated list of header names. +The following example configures a `DedupeResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -458,26 +558,30 @@ spring: filters: - DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin ---- +==== -This will remove duplicate values of `Access-Control-Allow-Credentials` and `Access-Control-Allow-Origin` response headers in cases when both the gateway CORS logic and the downstream add them. +This removes duplicate values of `Access-Control-Allow-Credentials` and `Access-Control-Allow-Origin` response headers in cases when both the gateway CORS logic and the downstream logic add them. -The DedupeResponseHeader filter also accepts an optional `strategy` parameter. The accepted values are `RETAIN_FIRST` (default), `RETAIN_LAST`, and `RETAIN_UNIQUE`. +The `DedupeResponseHeader` filter also accepts an optional `strategy` parameter. +The accepted values are `RETAIN_FIRST` (default), `RETAIN_LAST`, and `RETAIN_UNIQUE`. [[hystrix]] -=== Hystrix GatewayFilter Factory +=== The Hystrix `GatewayFilter` Factory -NOTE: https://cloud.spring.io/spring-cloud-netflix/multi/multi__modules_in_maintenance_mode.html[Netflix has put Hystrix in maintenance mode]. It is suggested you use the <> with Resilience4J as support for Hystrix will be removed in a future release. +NOTE: https://cloud.spring.io/spring-cloud-netflix/multi/multi__modules_in_maintenance_mode.html[Netflix has put Hystrix in maintenance mode]. We suggest you use the <> with Resilience4J, as support for Hystrix will be removed in a future release. https://github.com/Netflix/Hystrix[Hystrix] is a library from Netflix that implements the https://martinfowler.com/bliki/CircuitBreaker.html[circuit breaker pattern]. -The Hystrix GatewayFilter allows you to introduce circuit breakers to your gateway routes, protecting your services from cascading failures and allowing you to provide fallback responses in the event of downstream failures. +The Hystrix `GatewayFilter` lets you introduce circuit breakers to your gateway routes, protecting your services from cascading failures and letting you provide fallback responses in the event of downstream failures. -To enable Hystrix GatewayFilters in your project, add a dependency on `spring-cloud-starter-netflix-hystrix` from https://cloud.spring.io/spring-cloud-netflix/[Spring Cloud Netflix]. +To enable Hystrix `GatewayFilter` instances in your project, add a dependency on `spring-cloud-starter-netflix-hystrix` from https://cloud.spring.io/spring-cloud-netflix/[Spring Cloud Netflix]. -The Hystrix GatewayFilter Factory requires a single `name` parameter, which is the name of the `HystrixCommand`. +The Hystrix `GatewayFilter` factory requires a single `name` parameter, which is the name of the `HystrixCommand`. +The following example configures a Hystrix `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -489,13 +593,15 @@ spring: filters: - Hystrix=myCommandName ---- +==== -This wraps the remaining filters in a `HystrixCommand` with command name `myCommandName`. - -The Hystrix filter can also accept an optional `fallbackUri` parameter. Currently, only `forward:` schemed URIs are supported. If the fallback is called, the request will be forwarded to the controller matched by the URI. +This wraps the remaining filters in a `HystrixCommand` with a command name of `myCommandName`. +The Hystrix filter can also accept an optional `fallbackUri` parameter. Currently, only `forward:` schemed URIs are supported. If the fallback is called, the request is forwarded to the controller matched by the URI. +The following example configures such a fallback: .application.yml +==== [source,yaml] ---- spring: @@ -513,12 +619,15 @@ spring: fallbackUri: forward:/incaseoffailureusethis - RewritePath=/consumingserviceendpoint, /backingserviceendpoint ---- -This will forward to the `/incaseoffailureusethis` URI when the Hystrix fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing via the `lb` prefix on the destination URI. +==== + +This will forward to the `/incaseoffailureusethis` URI when the Hystrix fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing (defined the `lb` prefix on the destination URI). The primary scenario is to use the `fallbackUri` to an internal controller or handler within the gateway app. -However, it is also possible to reroute the request to a controller or handler in an external application, like so: +However, you can also reroute the request to a controller or handler in an external application, as follows: .application.yml +==== [source,yaml] ---- spring: @@ -539,37 +648,41 @@ spring: predicates: - Path=/fallback ---- +==== -In this example, there is no `fallback` endpoint or handler in the gateway application, however, there is one in another -app, registered under `http://localhost:9994`. +In this example, there is no `fallback` endpoint or handler in the gateway application. +However, there is one in another application, registered under `http://localhost:9994`. -In case of the request being forwarded to fallback, the Hystrix Gateway filter also provides the `Throwable` that has -caused it. It's added to the `ServerWebExchange` as the -`ServerWebExchangeUtils.HYSTRIX_EXECUTION_EXCEPTION_ATTR` attribute that can be used when -handling the fallback within the gateway app. +In case of the request being forwarded to the fallback, the Hystrix Gateway filter also provides the `Throwable` that has caused it. +It is added to the `ServerWebExchange` as the `ServerWebExchangeUtils.HYSTRIX_EXECUTION_EXCEPTION_ATTR` attribute, which you can use when handling the fallback within the gateway application. -For the external controller/ handler scenario, headers can be added with exception details. You can find more information -on it in the <>. +For the external controller/handler scenario, you can add headers with exception details. +You can find more information on doing so in the <>. -Hystrix settings (such as timeouts) can be configured with global defaults or on a route by route basis using application properties as explained on the https://github.com/Netflix/Hystrix/wiki/Configuration[Hystrix wiki]. +You can configured Hystrix settings (such as timeouts) with global defaults or on a route-by-route basis by using application properties, as explained on the https://github.com/Netflix/Hystrix/wiki/Configuration[Hystrix wiki]. -To set a 5 second timeout for the example route above, the following configuration would be used: +To set a five-second timeout for the example route shown earlier, you could use the following configuration: .application.yml +==== [source,yaml] +---- hystrix.command.fallbackcmd.execution.isolation.thread.timeoutInMilliseconds: 5000 +---- +==== [[spring-cloud-circuitbreaker-filter-factory]] === Spring Cloud CircuitBreaker GatewayFilter Factory -The Spring Cloud CircuitBreaker filter factory leverages the Spring Cloud CircuitBreaker APIs to wrap Gateway routes in -a circuit breaker. Spring Cloud CircuitBreaker supports two libraries which can be used with Spring Cloud Gateway, Hystrix -and Resilience4J. Since Netflix has places Hystrix in maintenance only mode we suggest you use Resilience4J. +The Spring Cloud CircuitBreaker GatewayFilter factory uses the Spring Cloud CircuitBreaker APIs to wrap Gateway routes in +a circuit breaker. Spring Cloud CircuitBreaker supports two libraries that can be used with Spring Cloud Gateway, Hystrix +and Resilience4J. Since Netflix has placed Hystrix in maintenance-only mode, we suggest that you use Resilience4J. -To enable the Spring Cloud CircuitBreaker filter you will need to either place `spring-cloud-starter-circuitbreaker-reactor-resilience4j` or -`spring-cloud-starter-netflix-hystrix` on the classpath. +To enable the Spring Cloud CircuitBreaker filter, you need to place either `spring-cloud-starter-circuitbreaker-reactor-resilience4j` or `spring-cloud-starter-netflix-hystrix` on the classpath. +The following example configures a Spring Cloud CircuitBreaker `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -581,15 +694,20 @@ spring: filters: - CircuitBreaker=myCircuitBreaker ---- +==== + To configure the circuit breaker, see the configuration for the underlying circuit breaker implementation you are using. * https://cloud.spring.io/spring-cloud-circuitbreaker/reference/html/spring-cloud-circuitbreaker.html[Resilience4J Documentation] * https://cloud.spring.io/spring-cloud-netflix/reference/html/[Hystrix Documentation] -The Spring Cloud CircuitBreaker filter can also accept an optional `fallbackUri` parameter. Currently, only `forward:` schemed URIs are supported. If the fallback is called, the request will be forwarded to the controller matched by the URI. - +The Spring Cloud CircuitBreaker filter can also accept an optional `fallbackUri` parameter. +Currently, only `forward:` schemed URIs are supported. +If the fallback is called, the request is forwarded to the controller matched by the URI. +The following example configures such a fallback: .application.yml +==== [source,yaml] ---- spring: @@ -607,8 +725,12 @@ spring: fallbackUri: forward:/inCaseOfFailureUseThis - RewritePath=/consumingServiceEndpoint, /backingServiceEndpoint ---- +==== + +The following listing does the same thing in Java: .Application.java +==== [source,java] ---- @Bean @@ -620,13 +742,16 @@ public RouteLocator routes(RouteLocatorBuilder builder) { .build(); } ---- +==== -This will forward to the `/inCaseofFailureUseThis` URI when the circuit breaker fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing via the `lb` prefix on the destination URI. +This example forwards to the `/inCaseofFailureUseThis` URI when the circuit breaker fallback is called. +Note that this example also demonstrates the (optional) Spring Cloud Netflix Ribbon load-balancing (defined by the `lb` prefix on the destination URI). -The primary scenario is to use the `fallbackUri` to an internal controller or handler within the gateway app. -However, it is also possible to reroute the request to a controller or handler in an external application, like so: +The primary scenario is to use the `fallbackUri` to define an internal controller or handler within the gateway application. +However, you can also reroute the request to a controller or handler in an external application, as follows: .application.yml +==== [source,yaml] ---- spring: @@ -647,25 +772,24 @@ spring: predicates: - Path=/fallback ---- +==== -In this example, there is no `fallback` endpoint or handler in the gateway application, however, there is one in another -app, registered under `http://localhost:9994`. +In this example, there is no `fallback` endpoint or handler in the gateway application. +However, there is one in another application, registered under `http://localhost:9994`. -In case of the request being forwarded to fallback, the Spring Cloud CircuitBreaker Gateway filter also provides the `Throwable` that has -caused it. It's added to the `ServerWebExchange` as the -`ServerWebExchangeUtils.CIRCUITBREAKER_EXECUTION_EXCEPTION_ATTR` attribute that can be used when -handling the fallback within the gateway app. +In case of the request being forwarded to fallback, the Spring Cloud CircuitBreaker Gateway filter also provides the `Throwable` that has caused it. +It is added to the `ServerWebExchange` as the `ServerWebExchangeUtils.CIRCUITBREAKER_EXECUTION_EXCEPTION_ATTR` attribute that can be used when handling the fallback within the gateway application. -For the external controller/handler scenario, headers can be added with exception details. You can find more information -on it in the <>. +For the external controller/handler scenario, headers can be added with exception details. +You can find more information on doing so in the <>. [[fallback-headers]] -=== FallbackHeaders GatewayFilter Factory +=== The `FallbackHeaders` `GatewayFilter` Factory -The `FallbackHeaders` factory allows you to add Hystrix or Spring Cloud CircuitBreaker execution exception details in headers of a request forwarded to -a `fallbackUri` in an external application, like in the following scenario: +The `FallbackHeaders` factory lets you add Hystrix or Spring Cloud CircuitBreaker execution exception details in the headers of a request forwarded to a `fallbackUri` in an external application, as in the following scenario: .application.yml +==== [source,yaml] ---- spring: @@ -690,26 +814,30 @@ spring: args: executionExceptionTypeHeaderName: Test-Header ---- +==== -In this example, after an execution exception occurs while running the circuit breaker, the request will be forwarded to -the `fallback` endpoint or handler in an app running on `localhost:9994`. The headers with the exception type, message -and -if available- root cause exception type and message will be added to that request by the `FallbackHeaders` filter. +In this example, after an execution exception occurs while running the circuit breaker, the request is forwarded to the `fallback` endpoint or handler in an application running on `localhost:9994`. +The headers with the exception type, message and (if available) root cause exception type and message are added to that request by the `FallbackHeaders` filter. -The names of the headers can be overwritten in the config by setting the values of the arguments listed below, along with -their default values: +You can overwrite the names of the headers in the configuration by setting the values of the following arguments (shown with their default values): * `executionExceptionTypeHeaderName` (`"Execution-Exception-Type"`) * `executionExceptionMessageHeaderName` (`"Execution-Exception-Message"`) * `rootCauseExceptionTypeHeaderName` (`"Root-Cause-Exception-Type"`) * `rootCauseExceptionMessageHeaderName` (`"Root-Cause-Exception-Message"`) -For more information of circuit beakers and the Gateway see the <> or -<>. +For more information on circuit beakers and the gatewayc see the <> or <>. -=== MapRequestHeader GatewayFilter Factory -The MapRequestHeader GatewayFilter Factory takes 'fromHeader' and 'toHeader' parameters. It creates a new named header (toHeader) and the value is extracted out of an existing named header (fromHeader) from the incoming http request. If the input header does not exist then the filter has no impact. If the new named header already exists then it's values will be augmented with the new values. +=== The `MapRequestHeader` `GatewayFilter` Factory + +The `MapRequestHeader` `GatewayFilter` factory takes `fromHeader` and `toHeader` parameters. +It creates a new named header (`toHeader`), and the value is extracted out of an existing named header (`fromHeader`) from the incoming http request. +If the input header does not exist, the filter has no impact. +If the new named header already exists, its values are augmented with the new values. +The following example configures a `MapRequestHeader`: .application.yml +==== [source,yaml] ---- spring: @@ -719,15 +847,19 @@ spring: - id: map_request_header_route uri: https://example.org filters: - - MapRequestHeader=Bar, X-Request-Foo + - MapRequestHeader=Blue, X-Request-Red ---- +==== -This will add `X-Request-Foo:` header to the downstream request's with updated values from the incoming http request `Bar` header. +This adds `X-Request-Red:` header to the downstream request with updated values from the incoming HTTP request's `Blue` header. -=== PrefixPath GatewayFilter Factory -The PrefixPath GatewayFilter Factory takes a single `prefix` parameter. +=== The `PrefixPath` `GatewayFilter` Factory + +The `PrefixPath` `GatewayFilter` factory takes a single `prefix` parameter. +The following example configures a `PrefixPath` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -739,13 +871,19 @@ spring: filters: - PrefixPath=/mypath ---- +==== -This will prefix `/mypath` to the path of all matching requests. So a request to `/hello`, would be sent to `/mypath/hello`. +This will prefix `/mypath` to the path of all matching requests. +So a request to `/hello` would be sent to `/mypath/hello`. -=== PreserveHostHeader GatewayFilter Factory -The PreserveHostHeader GatewayFilter Factory has no parameters. This filter sets a request attribute that the routing filter will inspect to determine if the original host header should be sent, rather than the host header determined by the http client. +=== The `PreserveHostHeader` `GatewayFilter` Factory + +The `PreserveHostHeader` `GatewayFilter` factory has no parameters. +This filter sets a request attribute that the routing filter inspects to determine if the original host header should be sent, rather than the host header determined by the HTTP client. +The following example configures a `PreserveHostHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -757,50 +895,71 @@ spring: filters: - PreserveHostHeader ---- +==== -=== RequestRateLimiter GatewayFilter Factory +=== The `RequestRateLimiter` `GatewayFilter` Factory -The RequestRateLimiter GatewayFilter Factory is uses a `RateLimiter` implementation to determine if the current request is allowed to proceed. If it is not, a status of `HTTP 429 - Too Many Requests` (by default) is returned. +The `RequestRateLimiter` `GatewayFilter` factory uses a `RateLimiter` implementation to determine if the current request is allowed to proceed. If it is not, a status of `HTTP 429 - Too Many Requests` (by default) is returned. -This filter takes an optional `keyResolver` parameter and parameters specific to the rate limiter (see below). +This filter takes an optional `keyResolver` parameter and parameters specific to the rate limiter (described later in this section). -`keyResolver` is a bean that implements the `KeyResolver` interface. In configuration, reference the bean by name using SpEL. `#{@myKeyResolver}` is a SpEL expression referencing a bean with the name `myKeyResolver`. +`keyResolver` is a bean that implements the `KeyResolver` interface. +In configuration, reference the bean by name using SpEL. +`#{@myKeyResolver}` is a SpEL expression that references a bean named `myKeyResolver`. +The following listing shows the `KeyResolver` interface: .KeyResolver.java +==== [source,java] ---- public interface KeyResolver { Mono resolve(ServerWebExchange exchange); } ---- +==== -The `KeyResolver` interface allows pluggable strategies to derive the key for limiting requests. In future milestones, there will be some `KeyResolver` implementations. +The `KeyResolver` interface lets pluggable strategies derive the key for limiting requests. +In future milestone releases, there will be some `KeyResolver` implementations. -The default implementation of `KeyResolver` is the `PrincipalNameKeyResolver` which retrieves the `Principal` from the `ServerWebExchange` and calls `Principal.getName()`. +The default implementation of `KeyResolver` is the `PrincipalNameKeyResolver`, which retrieves the `Principal` from the `ServerWebExchange` and calls `Principal.getName()`. -By default, if the `KeyResolver` does not find a key, requests will be denied. This behavior can be adjusted with the `spring.cloud.gateway.filter.request-rate-limiter.deny-empty-key` (true or false) and `spring.cloud.gateway.filter.request-rate-limiter.empty-key-status-code` properties. +By default, if the `KeyResolver` does not find a key, requests are denied. +You can adjust this behavior by setting the `spring.cloud.gateway.filter.request-rate-limiter.deny-empty-key` (`true` or `false`) and `spring.cloud.gateway.filter.request-rate-limiter.empty-key-status-code` properties. -NOTE: The RequestRateLimiter is not configurable via the "shortcut" notation. The example below is __invalid__ +[NOTE] +===== +The `RequestRateLimiter` is not configurable with the "shortcut" notation. The following example below is _invalid_: .application.properties +==== ---- # INVALID SHORTCUT CONFIGURATION spring.cloud.gateway.routes[0].filters[0]=RequestRateLimiter=2, 2, #{@userkeyresolver} ---- +==== +===== -==== Redis RateLimiter +==== The Redis `RateLimiter` -The redis implementation is based off of work done at https://stripe.com/blog/rate-limiters[Stripe]. It requires the use of the `spring-boot-starter-data-redis-reactive` Spring Boot starter. +The Redis implementation is based off of work done at https://stripe.com/blog/rate-limiters[Stripe]. +It requires the use of the `spring-boot-starter-data-redis-reactive` Spring Boot starter. The algorithm used is the https://en.wikipedia.org/wiki/Token_bucket[Token Bucket Algorithm]. -The `redis-rate-limiter.replenishRate` is how many requests per second do you want a user to be allowed to do, without any dropped requests. This is the rate that the token bucket is filled. +The `redis-rate-limiter.replenishRate` is how many requests per second you want a user to be allowed to do, without any dropped requests. +This is the rate at which the token bucket is filled. -The `redis-rate-limiter.burstCapacity` is the maximum number of requests a user is allowed to do in a single second. This is the number of tokens the token bucket can hold. Setting this value to zero will block all requests. +The `redis-rate-limiter.burstCapacity` is the maximum number of requests a user is allowed to do in a single second. +This is the number of tokens the token bucket can hold. +Setting this value to zero blocks all requests. -A steady rate is accomplished by setting the same value in `replenishRate` and `burstCapacity`. Temporary bursts can be allowed by setting `burstCapacity` higher than `replenishRate`. In this case, the rate limiter needs to be allowed some time between bursts (according to `replenishRate`), as 2 consecutive bursts will result in dropped requests (`HTTP 429 - Too Many Requests`). +A steady rate is accomplished by setting the same value in `replenishRate` and `burstCapacity`. +Temporary bursts can be allowed by setting `burstCapacity` higher than `replenishRate`. +In this case, the rate limiter needs to be allowed some time between bursts (according to `replenishRate`), as two consecutive bursts will result in dropped requests (`HTTP 429 - Too Many Requests`). +The following listing configures a `redis-rate-limiter`: .application.yml +==== [source,yaml] ---- spring: @@ -816,8 +975,12 @@ spring: redis-rate-limiter.burstCapacity: 20 ---- +==== + +The following example configures a KeyResolver in Java: .Config.java +==== [source,java] ---- @Bean @@ -825,12 +988,18 @@ KeyResolver userKeyResolver() { return exchange -> Mono.just(exchange.getRequest().getQueryParams().getFirst("user")); } ---- +==== -This defines a request rate limit of 10 per user. A burst of 20 is allowed, but the next second only 10 requests will be available. The `KeyResolver` is a simple one that gets the `user` request parameter (note: this is not recommended for production). +This defines a request rate limit of 10 per user. A burst of 20 is allowed, but, in the next second, only 10 requests are available. +The `KeyResolver` is a simple one that gets the `user` request parameter (note that this is not recommended for production). -A rate limiter can also be defined as a bean implementing the `RateLimiter` interface. In configuration, reference the bean by name using SpEL. `#{@myRateLimiter}` is a SpEL expression referencing a bean with the name `myRateLimiter`. +You can also define a rate limiter as a bean that implements the `RateLimiter` interface. +In configuration, you can reference the bean by name using SpEL. +`#{@myRateLimiter}` is a SpEL expression that references a bean with named `myRateLimiter`. +The following listing defines a rate limiter that uses the `KeyResolver` defined in the previous listing: .application.yml +==== [source,yaml] ---- spring: @@ -846,11 +1015,18 @@ spring: key-resolver: "#{@userKeyResolver}" ---- +==== -=== RedirectTo GatewayFilter Factory -The RedirectTo GatewayFilter Factory takes a `status` and a `url` parameter. The status should be a 300 series redirect http code, such as 301. The url should be a valid url. This will be the value of the `Location` header. +=== The `RedirectTo` `GatewayFilter` Factory + +The `RedirectTo` `GatewayFilter` factory takes two parameters, `status` and `url`. +The `status` parameter should be a 300 series redirect HTTP code, such as 301. +The `url` parameter should be a valid URL. +This is the value of the `Location` header. +The following listing configures a `RedirectTo` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -862,28 +1038,35 @@ spring: filters: - RedirectTo=302, https://acme.org ---- +==== This will send a status 302 with a `Location:https://acme.org` header to perform a redirect. -=== RemoveHopByHopHeadersFilter GatewayFilter Factory -The RemoveHopByHopHeadersFilter GatewayFilter Factory removes headers from forwarded requests. The default list of headers that is removed comes from the https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3[IETF]. +=== The `RemoveHopByHopHeadersFilter` `GatewayFilter` Factory + +The `RemoveHopByHopHeadersFilter` `GatewayFilter` Factory removes headers from forwarded requests. +The default list of headers that is removed comes from the https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3[IETF]. .The default removed headers are: - * Connection - * Keep-Alive - * Proxy-Authenticate - * Proxy-Authorization - * TE - * Trailer - * Transfer-Encoding - * Upgrade + * `Connection` + * `Keep-Alive` + * `Proxy-Authenticate` + * `Proxy-Authorization` + * `TE` + * `Trailer` + * `Transfer-Encoding` + * `Upgrade` -To change this, set the `spring.cloud.gateway.filter.remove-non-proxy-headers.headers` property to the list of header names to remove. +To change the removed headers, set the `spring.cloud.gateway.filter.remove-non-proxy-headers.headers` property to the list of header names to remove. -=== RemoveRequestHeader GatewayFilter Factory -The RemoveRequestHeader GatewayFilter Factory takes a `name` parameter. It is the name of the header to be removed. +=== The `RemoveRequestHeader` GatewayFilter Factory + +The `RemoveRequestHeader` `GatewayFilter` factory takes a `name` parameter. +It is the name of the header to be removed. +The following listing configures a `RemoveRequestHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -895,13 +1078,18 @@ spring: filters: - RemoveRequestHeader=X-Request-Foo ---- +==== -This will remove the `X-Request-Foo` header before it is sent downstream. +This removes the `X-Request-Foo` header before it is sent downstream. -=== RemoveResponseHeader GatewayFilter Factory -The RemoveResponseHeader GatewayFilter Factory takes a `name` parameter. It is the name of the header to be removed. +=== `RemoveResponseHeader` `GatewayFilter` Factory + +The `RemoveResponseHeader` `GatewayFilter` factory takes a `name` parameter. +It is the name of the header to be removed. +The following listing configures a `RemoveResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -913,17 +1101,21 @@ spring: filters: - RemoveResponseHeader=X-Response-Foo ---- +==== This will remove the `X-Response-Foo` header from the response before it is returned to the gateway client. -To remove any kind of sensitive header you should configure this filter for any routes that you may -want to do so. In addition you can configure this filter once using `spring.cloud.gateway.default-filters` -and have it applied to all routes. +To remove any kind of sensitive header, you should configure this filter for any routes for which you may want to do so. +In addition, you can configure this filter once by using `spring.cloud.gateway.default-filters` and have it applied to all routes. -=== RemoveRequestParameter GatewayFilter Factory -The RemoveRequestParameter GatewayFilter Factory takes a `name` parameter. It is the name of the query parameter to be removed. +=== The `RemoveRequestParameter` `GatewayFilter` Factory + +The `RemoveRequestParameter` `GatewayFilter` factory takes a `name` parameter. +It is the name of the query parameter to be removed. +The following example configures a `RemoveRequestParameter` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -933,15 +1125,20 @@ spring: - id: removerequestparameter_route uri: https://example.org filters: - - RemoveRequestParameter=foo + - RemoveRequestParameter=red ---- +==== -This will remove the `foo` parameter before it is sent downstream. +This will remove the `red` parameter before it is sent downstream. -=== RewritePath GatewayFilter Factory -The RewritePath GatewayFilter Factory takes a path `regexp` parameter and a `replacement` parameter. This uses Java regular expressions for a flexible way to rewrite the request path. +=== The `RewritePath` `GatewayFilter` Factory + +The `RewritePath` `GatewayFilter` factory takes a path `regexp` parameter and a `replacement` parameter. +This uses Java regular expressions for a flexible way to rewrite the request path. +The following listing configures a `RewritePath` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -953,15 +1150,20 @@ spring: predicates: - Path=/foo/** filters: - - RewritePath=/foo(?/?.*), $\{segment} + - RewritePath=/red(?/?.*), $\{segment} ---- +==== -For a request path of `/foo/bar`, this will set the path to `/bar` before making the downstream request. Notice the `$` Should be replaced with `$\` because of the YAML spec. +For a request path of `/red/blue`, this sets the path to `/blue` before making the downstream request. Note that the `$` should be replaced with `$\` because of the YAML specification. -=== RewriteLocationResponseHeader GatewayFilter Factory -The RewriteLocationResponseHeader GatewayFilter Factory modifies the value of `Location` response header, usually to get rid of backend specific details. It takes `stripVersionMode`, `locationHeaderName`, `hostValue`, and `protocolsRegex` parameters. +=== `RewriteLocationResponseHeader` `GatewayFilter` Factory + +The `RewriteLocationResponseHeader` `GatewayFilter` factory modifies the value of the `Location` response header, usually to get rid of backend-specific details. +It takes `stripVersionMode`, `locationHeaderName`, `hostValue`, and `protocolsRegex` parameters. +The following listing configures a `RewriteLocationResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -973,23 +1175,31 @@ spring: filters: - RewriteLocationResponseHeader=AS_IN_REQUEST, Location, , ---- +==== -For example, for a request `POST https://api.example.com/some/object/name`, `Location` response header value `https://object-service.prod.example.net/v2/some/object/id` will be rewritten as `https://api.example.com/some/object/id`. +For example, for a request of `POST https://api.example.com/some/object/name`, the `Location` response header value of `https://object-service.prod.example.net/v2/some/object/id` is rewritten as `https://api.example.com/some/object/id`. -Parameter `stripVersionMode` has the following possible values: `NEVER_STRIP`, `AS_IN_REQUEST` (default), `ALWAYS_STRIP`. +The `stripVersionMode` parameter has the following possible values: `NEVER_STRIP`, `AS_IN_REQUEST` (default), and `ALWAYS_STRIP`. - * `NEVER_STRIP` - Version will not be stripped, even if the original request path contains no version - * `AS_IN_REQUEST` - Version will be stripped only if the original request path contains no version - * `ALWAYS_STRIP` - Version will be stripped, even if the original request path contains version + * `NEVER_STRIP`: The version is not stripped, even if the original request path contains no version. + * `AS_IN_REQUEST` The version is stripped only if the original request path contains no version. + * `ALWAYS_STRIP` The version is always stripped, even if the original request path contains version. -Parameter `hostValue`, if provided, will be used to replace the `host:port` portion of the response `Location` header. If not provided, the value of the `Host` request header will be used. +The `hostValue` parameter, if provided, is used to replace the `host:port` portion of the response `Location` header. +If it is not provided, the value of the `Host` request header is used. -Parameter `protocolsRegex` must be a valid regex `String`, against which the protocol name will be matched. If not matched, the filter will do nothing. Default is `http|https|ftp|ftps`. +The `protocolsRegex` parameter must be a valid regex `String`, against which the protocol name is matched. +If it is not matched, the filter does nothing. +The default is `http|https|ftp|ftps`. -=== RewriteResponseHeader GatewayFilter Factory -The RewriteResponseHeader GatewayFilter Factory takes `name`, `regexp`, and `replacement` parameters. It uses Java regular expressions for a flexible way to rewrite the response header value. +=== The `RewriteResponseHeader` `GatewayFilter` Factory + +The `RewriteResponseHeader` `GatewayFilter` factory takes `name`, `regexp`, and `replacement` parameters. +It uses Java regular expressions for a flexible way to rewrite the response header value. +The following example configures a `RewriteResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -999,16 +1209,21 @@ spring: - id: rewriteresponseheader_route uri: https://example.org filters: - - RewriteResponseHeader=X-Response-Foo, , password=[^&]+, password=*** + - RewriteResponseHeader=X-Response-Red, , password=[^&]+, password=*** ---- +==== -For a header value of `/42?user=ford&password=omg!what&flag=true`, it will be set to `/42?user=ford&password=\***&flag=true` after making the downstream request. Please use `$\` to mean `$` because of the YAML spec. +For a header value of `/42?user=ford&password=omg!what&flag=true`, it is set to `/42?user=ford&password=\***&flag=true` after making the downstream request. +You must use `$\` to mean `$` because of the YAML specification. -=== SaveSession GatewayFilter Factory -The SaveSession GatewayFilter Factory forces a `WebSession::save` operation _before_ forwarding the call downstream. This is of particular use when -using something like https://projects.spring.io/spring-session/[Spring Session] with a lazy data store and need to ensure the session state has been saved before making the forwarded call. +=== The `SaveSession` `GatewayFilter` Factory + +The `SaveSession` `GatewayFilter` factory forces a `WebSession::save` operation _before_ forwarding the call downstream. +This is of particular use when using something like https://projects.spring.io/spring-session/[Spring Session] with a lazy data store and you need to ensure the session state has been saved before making the forwarded call. +The following example configures a `SaveSession` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1022,55 +1237,59 @@ spring: filters: - SaveSession ---- +==== -If you are integrating https://projects.spring.io/spring-security/[Spring Security] with Spring Session, and want to ensure security details have been forwarded to the remote process, this is critical. +If you integrate https://projects.spring.io/spring-security/[Spring Security] with Spring Session and want to ensure security details have been forwarded to the remote process, this is critical. -=== SecureHeaders GatewayFilter Factory -The SecureHeaders GatewayFilter Factory adds a number of headers to the response at the recommendation from https://blog.appcanary.com/2017/http-security-headers.html[this blog post]. +=== The `SecureHeaders` `GatewayFilter` Factory -.The following headers are added (along with default values): - * `X-Xss-Protection:1; mode=block` - * `Strict-Transport-Security:max-age=631138519` - * `X-Frame-Options:DENY` - * `X-Content-Type-Options:nosniff` - * `Referrer-Policy:no-referrer` - * `Content-Security-Policy:default-src 'self' https:; font-src 'self' https: data:; img-src 'self' https: data:; object-src 'none'; script-src https:; style-src 'self' https: 'unsafe-inline'` - * `X-Download-Options:noopen` - * `X-Permitted-Cross-Domain-Policies:none` +The `SecureHeaders` `GatewayFilter` factory adds a number of headers to the response, per the recommendation made in https://blog.appcanary.com/2017/http-security-headers.html[this blog post]. -To change the default values set the appropriate property in the `spring.cloud.gateway.filter.secure-headers` namespace: +The following headers (shown with their default values) are added: -.Property to change: - * `xss-protection-header` - * `strict-transport-security` - * `frame-options` - * `content-type-options` - * `referrer-policy` - * `content-security-policy` - * `download-options` - * `permitted-cross-domain-policies` +* `X-Xss-Protection:1 (mode=block`) +* `Strict-Transport-Security (max-age=631138519`) +* `X-Frame-Options (DENY)` +* `X-Content-Type-Options (nosniff)` +* `Referrer-Policy (no-referrer)` +* `Content-Security-Policy (default-src 'self' https:; font-src 'self' https: data:; img-src 'self' https: data:; object-src 'none'; script-src https:; style-src 'self' https: 'unsafe-inline)'` +* `X-Download-Options (noopen)` +* `X-Permitted-Cross-Domain-Policies (none)` -To disable the default values set the property `spring.cloud.gateway.filter.secure-headers.disable` with comma separated values. +To change the default values, set the appropriate property in the `spring.cloud.gateway.filter.secure-headers` namespace. +The following properties are available: -NOTE: Need use lowercase and full name of secure headers. +* `xss-protection-header` +* `strict-transport-security` +* `x-frame-options` +* `x-content-type-options` +* `referrer-policy` +* `content-security-policy` +* `x-download-options` +* `x-permitted-cross-domain-policies` -.The following values can use: - * `x-xss-protection` - * `strict-transport-security` - * `x-frame-options` - * `x-content-type-options` - * `referrer-policy` - * `content-security-policy` - * `x-download-options` - * `x-permitted-cross-domain-policies` +To disable the default values set the `spring.cloud.gateway.filter.secure-headers.disable` property with comma-separated values. +The following example shows how to do so: -.Example: -`spring.cloud.gateway.filter.secure-headers.disable=x-frame-options,strict-transport-security` +==== +[source] +---- +spring.cloud.gateway.filter.secure-headers.disable=x-frame-options,strict-transport-security +---- +==== -=== SetPath GatewayFilter Factory -The SetPath GatewayFilter Factory takes a path `template` parameter. It offers a simple way to manipulate the request path by allowing templated segments of the path. This uses the uri templates from Spring Framework. Multiple matching segments are allowed. +NOTE: The lowercase full name of the secure header needs to be used to disable it.. + +=== The `SetPath` `GatewayFilter` Factory + +The `SetPath` `GatewayFilter` factory takes a path `template` parameter. +It offers a simple way to manipulate the request path by allowing templated segments of the path. +This uses the URI templates from Spring Framework. +Multiple matching segments are allowed. +The following example configures a `SetPath` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1080,17 +1299,21 @@ spring: - id: setpath_route uri: https://example.org predicates: - - Path=/foo/{segment} + - Path=/red/{segment} filters: - SetPath=/{segment} ---- +==== -For a request path of `/foo/bar`, this will set the path to `/bar` before making the downstream request. +For a request path of `/red/blue`, this sets the path to `/blue` before making the downstream request. -=== SetRequestHeader GatewayFilter Factory -The SetRequestHeader GatewayFilter Factory takes `name` and `value` parameters. +=== The `SetRequestHeader` `GatewayFilter` Factory + +The `SetRequestHeader` `GatewayFilter` factory takes `name` and `value` parameters. +The following listing configures a `SetRequestHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1100,14 +1323,19 @@ spring: - id: setrequestheader_route uri: https://example.org filters: - - SetRequestHeader=X-Request-Foo, Bar + - SetRequestHeader=X-Request-Red, Blue ---- +==== -This GatewayFilter replaces all headers with the given name, rather than adding. So if the downstream server responded with a `X-Request-Foo:1234`, this would be replaced with `X-Request-Foo:Bar`, which is what the downstream service would receive. +This `GatewayFilter` replaces (rather than adding) all headers with the given name. +So, if the downstream server responded with a `X-Request-Red:1234`, this would be replaced with `X-Request-Red:Blue`, which is what the downstream service would receive. -SetRequestHeader is aware of URI variables used to match a path or host. URI variables may be used in the value and will be expanded at runtime. +`SetRequestHeader` is aware of URI variables used to match a path or host. +URI variables may be used in the value and are expanded at runtime. +The following example configures an `SetRequestHeader` `GatewayFilter` that uses a variable: .application.yml +==== [source,yaml] ---- spring: @@ -1121,11 +1349,15 @@ spring: filters: - SetRequestHeader=foo, bar-{segment} ---- +==== -=== SetResponseHeader GatewayFilter Factory -The SetResponseHeader GatewayFilter Factory takes `name` and `value` parameters. +=== The `SetResponseHeader` `GatewayFilter` Factory + +The `SetResponseHeader` `GatewayFilter` factory takes `name` and `value` parameters. +The following listing configures a `SetResponseHeader` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1135,14 +1367,19 @@ spring: - id: setresponseheader_route uri: https://example.org filters: - - SetResponseHeader=X-Response-Foo, Bar + - SetResponseHeader=X-Response-Red, Blue ---- +==== -This GatewayFilter replaces all headers with the given name, rather than adding. So if the downstream server responded with a `X-Response-Foo:1234`, this would be replaced with `X-Response-Foo:Bar`, which is what the gateway client would receive. +This GatewayFilter replaces (rather than adding) all headers with the given name. +So, if the downstream server responded with a `X-Response-Red:1234`, this is replaced with `X-Response-Red:Blue`, which is what the gateway client would receive. -SetResponseHeader is aware of URI variables used to match a path or host. URI variables may be used in the value and will be expanded at runtime. +`SetResponseHeader` is aware of URI variables used to match a path or host. +URI variables may be used in the value and will be expanded at runtime. +The following example configures an `SetResponseHeader` `GatewayFilter` that uses a variable: .application.yml +==== [source,yaml] ---- spring: @@ -1156,11 +1393,17 @@ spring: filters: - SetResponseHeader=foo, bar-{segment} ---- +==== -=== SetStatus GatewayFilter Factory -The SetStatus GatewayFilter Factory takes a single `status` parameter. It must be a valid Spring `HttpStatus`. It may be the integer value `404` or the string representation of the enumeration `NOT_FOUND`. +=== The `SetStatus` `GatewayFilter` Factory + +The `SetStatus` `GatewayFilter` factory takes a single parameter, `status`. +It must be a valid Spring `HttpStatus`. +It may be the integer value `404` or the string representation of the enumeration: `NOT_FOUND`. +The following listing configures a `SetStatus` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1176,12 +1419,15 @@ spring: filters: - SetStatus=401 ---- +==== -In either case, the HTTP status of the response will be set to 401. +In either case, the HTTP status of the response is set to 401. -The SetStatus GatewayFilter can be configured to return the original HTTP status code from the proxied request in a header in the response. Header will be added to the response if configured using following property. +You can configure the `SetStatus` `GatewayFilter` to return the original HTTP status code from the proxied request in a header in the response. +The header is added to the response if configured with the following property: .application.yml +==== [source,yaml] ---- spring: @@ -1190,11 +1436,16 @@ spring: set-status: original-status-header-name: original-http-status ---- +==== -=== StripPrefix GatewayFilter Factory -The StripPrefix GatewayFilter Factory takes one parameter, `parts`. The `parts` parameter indicated the number of parts in the path to strip from the request before sending it downstream. +=== The `StripPrefix` `GatewayFilter` Factory + +The `StripPrefix` `GatewayFilter` factory takes one parameter, `parts`. +The `parts` parameter indicates the number of parts in the path to strip from the request before sending it downstream. +The following listing configures a `StripPrefix` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1208,31 +1459,36 @@ spring: filters: - StripPrefix=2 ---- +==== -When a request is made through the gateway to `/name/bar/foo` the request made to `nameservice` will look like `https://nameservice/foo`. +When a request is made through the gateway to `/name/blue/red`, the request made to `nameservice` looks like `https://nameservice/red`. -=== Retry GatewayFilter Factory +=== The Retry `GatewayFilter` Factory -The Retry GatewayFilter Factory support following set of parameters: +The Retry `GatewayFilter` factory supports the following parameters: -* `retries`: the number of retries that should be attempted -* `statuses`: the HTTP status codes that should be retried, represented using `org.springframework.http.HttpStatus` -* `methods`: the HTTP methods that should be retried, represented using `org.springframework.http.HttpMethod` -* `series`: the series of status codes to be retried, represented using `org.springframework.http.HttpStatus.Series` -* `exceptions`: list of exceptions thrown that should be retried -* `backoff`: configured exponential backoff for the retries. Retries are performed after a backoff interval of `firstBackoff * (factor ^ n)` where `n` is the iteration. -If `maxBackoff` is configured, the maximum backoff applied will be limited to `maxBackoff`. -If `basedOnPreviousValue` is true, backoff will be calculated using `prevBackoff * factor`. +* `retries`: The number of retries that should be attempted. +* `statuses`: The HTTP status codes that should be retried, represented by using `org.springframework.http.HttpStatus`. +* `methods`: The HTTP methods that should be retried, represented by using `org.springframework.http.HttpMethod`. +* `series`: The series of status codes to be retried, represented by using `org.springframework.http.HttpStatus.Series`. +* `exceptions`: A list of thrown exceptions that should be retried. +* `backoff`: The configured exponential backoff for the retries. +Retries are performed after a backoff interval of `firstBackoff * (factor ^ n)`, where `n` is the iteration. +If `maxBackoff` is configured, the maximum backoff applied is limited to `maxBackoff`. +If `basedOnPreviousValue` is true, the backoff is calculated byusing `prevBackoff * factor`. -The following defaults are configured for `Retry` filter if enabled: +The following defaults are configured for `Retry` filter, if enabled: -* `retries` -- 3 times -* `series` -- 5XX series -* `methods` -- GET method -* `exceptions` -- `IOException` and `TimeoutException` -* `backoff` -- disabled +* `retries`: Three times +* `series`: 5XX series +* `methods`: GET method +* `exceptions`: `IOException` and `TimeoutException` +* `backoff`: disabled + +The following listing configures a Retry `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1254,15 +1510,23 @@ spring: factor: 2 basedOnPreviousValue: false ---- +==== -NOTE: The retry filter does not currently support retrying with a body (e.g. for POST or PUT requests with a body). +NOTE: The retry filter does not currently support retrying with a body (for example, for POST or PUT requests with a body). -NOTE: When using the retry filter with a `forward:` prefixed URL, the target endpoint should be written carefully so that in case of an error it does not do anything that could result in a response being sent to the client and committed. For example, if the target endpoint is an annotated controller, the target controller method should not return `ResponseEntity` with an error status code. Instead it should throw an `Exception`, or signal an error, e.g. via a `Mono.error(ex)` return value, which the retry filter can be configured to handle by retrying. +NOTE: When using the retry filter with a `forward:` prefixed URL, the target endpoint should be written carefully so that, in case of an error, it does not do anything that could result in a response being sent to the client and committed. +For example, if the target endpoint is an annotated controller, the target controller method should not return `ResponseEntity` with an error status code. +Instead, it should throw an `Exception` or signal an error (for example, through a `Mono.error(ex)` return value), which the retry filter can be configured to handle by retrying. -=== RequestSize GatewayFilter Factory -The RequestSize GatewayFilter Factory can restrict a request from reaching the downstream service , when the request size is greater than the permissible limit. The filter takes `RequestSize` as parameter which is the permissible size limit of the request defined in bytes. +=== The `RequestSize` `GatewayFilter` Factory + +When the request size is greater than the permissible limit, the `RequestSize` `GatewayFilter` factory can restrict a request from reaching the downstream service. +The filter takes a `RequestSize` parameter. +It is the permissible size limit of the request defined in bytes. +The following listing configures a `RequestSize` `GatewayFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1278,21 +1542,30 @@ spring: args: maxSize: 5000000 ---- +==== -The RequestSize GatewayFilter Factory set the response status as `413 Payload Too Large` with a additional header `errorMessage` when the Request is rejected due to size. Following is an example of such an `errorMessage` . +The `RequestSize` `GatewayFilter` factory sets the response status as `413 Payload Too Large` with an additional header `errorMessage` when the request is rejected due to size. The following example shows such an `errorMessage`: -`errorMessage` : `Request size is larger than permissible limit. Request size is 6.0 MB where permissible limit is 5.0 MB` +==== +[source] +---- +errorMessage` : `Request size is larger than permissible limit. Request size is 6.0 MB where permissible limit is 5.0 MB +---- +==== -NOTE: The default Request size will be set to 5 MB if not provided as filter argument in route definition. +NOTE: The default request size is set to five MB if not provided as a filter argument in the route definition. -=== Modify Request Body GatewayFilter Factory +=== Modify a Request Body `GatewayFilter` Factory -*This filter is considered BETA and the API may change in the future* +CAUTION: This filter is considered BETA, and the API may change in the future. -This filter can be used to modify the request body before it is sent downstream by the Gateway. +You can use this filter to modify the request body before it is sent downstream by the gateway. -NOTE: This filter can only be configured using the Java DSL +NOTE: This filter can be configured only by using the Java DSL. +The following listing shows how to modify a request body `GatewayFilter`: + +==== [source,java] ---- @Bean @@ -1323,15 +1596,19 @@ static class Hello { } } ---- +==== -=== Modify Response Body GatewayFilter Factory +=== Modify a Response Body `GatewayFilter` Factory -*This filter is considered BETA and the API may change in the future* +CAUTION: This filter is considered BETA and the API may change in the future. -This filter can be used to modify the response body before it is sent back to the Client. +You can use this filter to modify the response body before it is sent back to the client. -NOTE: This filter can only be configured using the Java DSL +NOTE: This filter can be configured only by using the Java DSL. +The following listing shows how to modify a response body `GatewayFilter`: + +==== [source,java] ---- @Bean @@ -1344,35 +1621,46 @@ public RouteLocator routes(RouteLocatorBuilder builder) { .build(); } ---- - +==== === Default Filters -If you would like to add a filter and apply it to all routes you can use `spring.cloud.gateway.default-filters`. -This property takes a list of filters +To add a filter and apply it to all routes, you can use `spring.cloud.gateway.default-filters`. +This property takes a list of filters. +The following listing defines a set of default filters: .application.yml +==== [source,yaml] ---- spring: cloud: gateway: default-filters: - - AddResponseHeader=X-Response-Default-Foo, Default-Bar + - AddResponseHeader=X-Response-Default-Red, Default-Blue - PrefixPath=/httpbin ---- +==== == Global Filters -The `GlobalFilter` interface has the same signature as `GatewayFilter`. These are special filters that are conditionally applied to all routes. (This interface and usage are subject to change in future milestones). +The `GlobalFilter` interface has the same signature as `GatewayFilter`. +These are special filters that are conditionally applied to all routes. -=== Combined Global Filter and GatewayFilter Ordering +NOTE: This interface and its usage are subject to change in future milestone releases. -When a request comes in (and matches a Route) the Filtering Web Handler will add all instances of `GlobalFilter` and all route specific instances of `GatewayFilter` to a filter chain. This combined filter chain is sorted by the `org.springframework.core.Ordered` interface, which can be set by implementing the `getOrder()` method. +[[gateway-combined-global-filter-and-gatewayfilter-ordering]] +=== Combined Global Filter and `GatewayFilter` Ordering -As Spring Cloud Gateway distinguishes between "pre" and "post" phases for filter logic execution (see: <>), the filter with the highest precedence will be the first in the "pre"-phase and the last in the "post"-phase. +When a request matches a route, the filtering web handler adds all instances of `GlobalFilter` and all route-specific instances of `GatewayFilter` to a filter chain. +This combined filter chain is sorted by the `org.springframework.core.Ordered` interface, which you can set by implementing the `getOrder()` method. + +As Spring Cloud Gateway distinguishes between "`pre`" and "`post`" phases for filter logic execution (see <>), the filter with the highest precedence is the first in the "`pre`"-phase and the last in the "`post`"-phase. + +The following listing configures a filter chain: .ExampleConfiguration.java +==== [source,java] ---- @Bean @@ -1394,16 +1682,26 @@ public class CustomGlobalFilter implements GlobalFilter, Ordered { } } ---- +==== === Forward Routing Filter -The `ForwardRoutingFilter` looks for a URI in the exchange attribute `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. If the url has a `forward` scheme (ie `forward:///localendpoint`), it will use the Spring `DispatcherHandler` to handler the request. The path part of the request URL will be overridden with the path in the forward URL. The unmodified original url is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. +The `ForwardRoutingFilter` looks for a URI in the exchange attribute `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. +If the URL has a `forward` scheme (such as `forward:///localendpoint`), it uses the Spring `DispatcherHandler` to handle the request. +The path part of the request URL is overridden with the path in the forward URL. +The unmodified original URL is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. -=== LoadBalancerClient Filter +=== The `LoadBalancerClient` Filter -The `LoadBalancerClientFilter` looks for a URI in the exchange attribute `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. If the url has a `lb` scheme (ie `lb://myservice`), it will use the Spring Cloud `LoadBalancerClient` to resolve the name (`myservice` in the previous example) to an actual host and port and replace the URI in the same attribute. The unmodified original url is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. The filter will also look in the `ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR` attribute to see if it equals `lb` and then the same rules apply. +The `LoadBalancerClientFilter` looks for a URI in the exchange attribute named `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. +If the URL has a scheme of `lb` (such as `lb://myservice`), it uses the Spring Cloud `LoadBalancerClient` to resolve the name (`myservice` in this case) to an actual host and port and replaces the URI in the same attribute. +The unmodified original URL is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. +The filter also looks in the `ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR` attribute to see if it equals `lb`. +If so, the same rules apply. +The following listing configures a `LoadBalancerClientFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1415,33 +1713,37 @@ spring: predicates: - Path=/service/** ---- +==== -NOTE: By default when a service instance cannot be found in the `LoadBalancer` a `503` will be returned. +NOTE: By default, when a service instance cannot be found in the `LoadBalancer`, a `503` is returned. You can configure the Gateway to return a `404` by setting `spring.cloud.gateway.loadbalancer.use404=true`. -NOTE: The `isSecure` value of the `ServiceInstance` returned from the `LoadBalancer` will override -the scheme specified in the request made to the Gateway. For example, if the request comes into the Gateway over `HTTPS` -but the `ServiceInstance` indicates it is not secure, then the downstream request will be made over -`HTTP`. The opposite situation can also apply. However if `GATEWAY_SCHEME_PREFIX_ATTR` is specified for the -route in the Gateway configuration, the prefix will be stripped and the resulting scheme from the -route URL will override the `ServiceInstance` configuration. +NOTE: The `isSecure` value of the `ServiceInstance` returned from the `LoadBalancer` overrides +the scheme specified in the request made to the Gateway. +For example, if the request comes into the Gateway over `HTTPS` +but the `ServiceInstance` indicates it is not secure, the downstream request is made over +`HTTP`. +The opposite situation can also apply. +However, if `GATEWAY_SCHEME_PREFIX_ATTR` is specified for the +route in the Gateway configuration, the prefix is stripped and the resulting scheme from the +route URL overrides the `ServiceInstance` configuration. -WARNING: `LoadBalancerClientFilter` uses a blocking Ribbon `LoadBalancerClient` under the hood. +WARNING: `LoadBalancerClientFilter` uses a blocking ribbon `LoadBalancerClient` under the hood. We suggest you use <>. -You can switch to using it by setting the value of the `spring.cloud.loadbalancer.ribbon.enabled` to `false`. +You can switch to it by setting the value of the `spring.cloud.loadbalancer.ribbon.enabled` to `false`. [[reactive-loadbalancer-client-filter]] -=== ReactiveLoadBalancerClientFilter +=== The `ReactiveLoadBalancerClientFilter` -The `ReactiveLoadBalancerClientFilter` looks for a URI in the exchange attribute -`ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. If the url has a `lb` scheme (ie `lb://myservice`), -it will use the Spring Cloud `ReactorLoadBalancer` to resolve the name (`myservice` in the previous example) -to an actual host and port and replace the URI in the same attribute. The unmodified -original url is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. -The filter will also look in the `ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR` attribute to see if it equals -`lb` and then the same rules apply. +The `ReactiveLoadBalancerClientFilter` looks for a URI in the exchange attribute named `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`. +If the URL has a `lb` scheme (such as `lb://myservice`), it uses the Spring Cloud `ReactorLoadBalancer` to resolve the name (`myservice` in this example) to an actual host and port and replaces the URI in the same attribute. +The unmodified original URL is appended to the list in the `ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR` attribute. +The filter also looks in the `ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR` attribute to see if it equals `lb`. +If so, the same rules apply. +The following listing configures a `ReactiveLoadBalancerClientFilter`: .application.yml +==== [source,yaml] ---- spring: @@ -1453,40 +1755,50 @@ spring: predicates: - Path=/service/** ---- +==== -NOTE: By default when a service instance cannot be found by the `ReactorLoadBalancer`, a `503` will be returned. -You can configure the Gateway to return a `404` by setting `spring.cloud.gateway.loadbalancer.use404=true`. +NOTE: By default, when a service instance cannot be found by the `ReactorLoadBalancer`, a `503` is returned. +You can configure the gateway to return a `404` by setting `spring.cloud.gateway.loadbalancer.use404=true`. -NOTE: The `isSecure` value of the `ServiceInstance` returned from the `ReactiveLoadBalancerClientFilter` will override -the scheme specified in the request made to the Gateway. For example, if the request comes into the Gateway over `HTTPS` -but the `ServiceInstance` indicates it is not secure, then the downstream request will be made over -`HTTP`. The opposite situation can also apply. However if `GATEWAY_SCHEME_PREFIX_ATTR` is specified for the -route in the Gateway configuration, the prefix will be stripped and the resulting scheme from the -route URL will override the `ServiceInstance` configuration. +NOTE: The `isSecure` value of the `ServiceInstance` returned from the `ReactiveLoadBalancerClientFilter` overrides +the scheme specified in the request made to the Gateway. +For example, if the request comes into the Gateway over `HTTPS` but the `ServiceInstance` indicates it is not secure, the downstream request is made over `HTTP`. +The opposite situation can also apply. +However, if `GATEWAY_SCHEME_PREFIX_ATTR` is specified for the route in the Gateway configuration, the prefix is stripped and the resulting scheme from the route URL overrides the `ServiceInstance` configuration. -=== Netty Routing Filter +=== The Netty Routing Filter -The Netty Routing Filter runs if the url located in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute has a `http` or `https` scheme. It uses the Netty `HttpClient` to make the downstream proxy request. The response is put in the `ServerWebExchangeUtils.CLIENT_RESPONSE_ATTR` exchange attribute for use in a later filter. (There is an experimental `WebClientHttpRoutingFilter` that performs the same function, but does not require netty) +The Netty routing filter runs if the URL located in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute has a `http` or `https` scheme. +It uses the Netty `HttpClient` to make the downstream proxy request. +The response is put in the `ServerWebExchangeUtils.CLIENT_RESPONSE_ATTR` exchange attribute for use in a later filter. +(There is also an experimental `WebClientHttpRoutingFilter` that performs the same function but does not require Netty.) -=== Netty Write Response Filter +=== The Netty Write Response Filter -The `NettyWriteResponseFilter` runs if there is a Netty `HttpClientResponse` in the `ServerWebExchangeUtils.CLIENT_RESPONSE_ATTR` exchange attribute. It is run after all other filters have completed and writes the proxy response back to the gateway client response. (There is an experimental `WebClientWriteResponseFilter` that performs the same function, but does not require netty) +The `NettyWriteResponseFilter` runs if there is a Netty `HttpClientResponse` in the `ServerWebExchangeUtils.CLIENT_RESPONSE_ATTR` exchange attribute. +It runs after all other filters have completed and writes the proxy response back to the gateway client response. +(There is also an experimental `WebClientWriteResponseFilter` that performs the same function but does not require Netty.) -=== RouteToRequestUrl Filter +=== The `RouteToRequestUrl` Filter -The `RouteToRequestUrlFilter` runs if there is a `Route` object in the `ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR` exchange attribute. It creates a new URI, based off of the request URI, but updated with the URI attribute of the `Route` object. The new URI is placed in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute. +If there is a `Route` object in the `ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR` exchange attribute, the `RouteToRequestUrlFilter` runs. +It creates a new URI, based off of the request URI but updated with the URI attribute of the `Route` object. +The new URI is placed in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute`. If the URI has a scheme prefix, such as `lb:ws://serviceid`, the `lb` scheme is stripped from the URI and placed in the `ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR` for use later in the filter chain. -=== Websocket Routing Filter +=== The Websocket Routing Filter -The Websocket Routing Filter runs if the url located in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute has a `ws` or `wss` scheme. It uses the Spring Web Socket infrastructure to forward the Websocket request downstream. +If the URL located in the `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR` exchange attribute has a `ws` or `wss` scheme, the websocket routing rilter runs. It uses the Spring WebSocket infrastructure to forward the websocket request downstream. -Websockets may be load-balanced by prefixing the URI with `lb`, such as `lb:ws://serviceid`. +You can load-balance websockets by prefixing the URI with `lb`, such as `lb:ws://serviceid`. -NOTE: If you are using https://github.com/sockjs[SockJS] as a fallback over normal http, you should configure a normal HTTP route as well as the Websocket Route. +NOTE: If you use https://github.com/sockjs[SockJS] as a fallback over normal HTTP, you should configure a normal HTTP route as well as the websocket Route. + +The following listing configures a websocket routing filter: .application.yml +==== [source,yaml] ---- spring: @@ -1504,36 +1816,40 @@ spring: predicates: - Path=/websocket/** ---- +==== -=== Gateway Metrics Filter +=== The Gateway Metrics Filter -To enable Gateway Metrics add spring-boot-starter-actuator as a project dependency. Then, by default, the Gateway Metrics Filter runs as long as the property `spring.cloud.gateway.metrics.enabled` is not set to `false`. This filter adds a timer metric named "gateway.requests" with the following tags: +To enable gateway metrics, add spring-boot-starter-actuator as a project dependency. Then, by default, the gateway metrics filter runs as long as the property `spring.cloud.gateway.metrics.enabled` is not set to `false`. This filter adds a timer metric named `gateway.requests` with the following tags: -* `routeId`: The route id -* `routeUri`: The URI that the API will be routed to -* `outcome`: Outcome as classified by link:https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/http/HttpStatus.Series.html[HttpStatus.Series] -* `status`: Http Status of the request returned to the client -* `httpStatusCode`: Http Status of the request returned to the client -* `httpMethod`: The Http method used for the request +* `routeId`: The route ID. +* `routeUri`: The URI to which the API is routed. +* `outcome`: The outcome, as classified by link:https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/http/HttpStatus.Series.html[HttpStatus.Series]. +* `status`: The HTTP status of the request returned to the client. +* `httpStatusCode`: The HTTP Status of the request returned to the client. +* `httpMethod`: The HTTP method used for the request. -These metrics are then available to be scraped from ``/actuator/metrics/gateway.requests`` and can be easily integrated with Prometheus to create a link:images/gateway-grafana-dashboard.jpeg[Grafana] link:gateway-grafana-dashboard.json[dashboard]. +These metrics are then available to be scraped from `/actuator/metrics/gateway.requests` and can be easily integrated with Prometheus to create a link:images/gateway-grafana-dashboard.jpeg[Grafana] link:gateway-grafana-dashboard.json[dashboard]. -NOTE: To enable the prometheus endpoint add micrometer-registry-prometheus as a project dependency. +NOTE: To enable the prometheus endpoint, add `micrometer-registry-prometheus` as a project dependency. === Marking An Exchange As Routed -After the Gateway has routed a `ServerWebExchange` it will mark that exchange as "routed" by adding `gatewayAlreadyRouted` -to the exchange attributes. Once a request has been marked as routed, other routing filters will not route the request again, -essentially skipping the filter. There are convenience methods that you can use to mark an exchange as routed +After the gateway has routed a `ServerWebExchange`, it marks that exchange as "`routed`" by adding `gatewayAlreadyRouted` +to the exchange attributes. Once a request has been marked as routed, other routing filters will not route the request again, +essentially skipping the filter. There are convenience methods that you can use to mark an exchange as routed or check if an exchange has already been routed. -* `ServerWebExchangeUtils.isAlreadyRouted` takes a `ServerWebExchange` object and checks if it has been "routed" -* `ServerWebExchangeUtils.setAlreadyRouted` takes a `ServerWebExchange` object and marks it as "routed" +* `ServerWebExchangeUtils.isAlreadyRouted` takes a `ServerWebExchange` object and checks if it has been "`routed`". +* `ServerWebExchangeUtils.setAlreadyRouted` takes a `ServerWebExchange` object and marks it as "`routed`". -== TLS / SSL -The Gateway can listen for requests on https by following the usual Spring server configuration. Example: +== TLS and SSL + +The gateway can listen for requests on HTTPS by following the usual Spring server configuration. +The following example shows how to do so: .application.yml +==== [source,yaml] ---- server: @@ -1544,10 +1860,13 @@ server: key-store: classpath:scg-keystore.p12 key-store-type: PKCS12 ---- +==== -Gateway routes can be routed to both http and https backends. If routing to a https backend then the Gateway can be configured to trust all downstream certificates with the following configuration: +You can route gateway routes to both HTTP and HTTPS backends. +If you are routing to an HTTPS backend, you can configure the gateway to trust all downstream certificates with the following configuration: .application.yml +==== [source,yaml] ---- spring: @@ -1557,10 +1876,13 @@ spring: ssl: useInsecureTrustManager: true ---- +==== -Using an insecure trust manager is not suitable for production. For a production deployment the Gateway can be configured with a set of known certificates that it can trust with the following configuration: +Using an insecure trust manager is not suitable for production. +For a production deployment, you can configure the gateway with a set of known certificates that it can trust with the following configuration: .application.yml +==== [source,yaml] ---- spring: @@ -1572,14 +1894,19 @@ spring: - cert1.pem - cert2.pem ---- +==== -If the Spring Cloud Gateway is not provisioned with trusted certificates the default trust store is used (which can be overridden with system property javax.net.ssl.trustStore). +If the Spring Cloud Gateway is not provisioned with trusted certificates, the default trust store is used (which you can override by setting the `javax.net.ssl.trustStore` system property). === TLS Handshake -The Gateway maintains a client pool that it uses to route to backends. When communicating over https the client initiates a TLS handshake. A number of timeouts are associated with this handshake. These timeouts can be configured (defaults shown): +The gateway maintains a client pool that it uses to route to backends. +When communicating over HTTPS, the client initiates a TLS handshake. +A number of timeouts are associated with this handshake. +You can configure these timeouts can be configured (defaults shown) as follows: .application.yml +==== [source,yaml] ---- spring: @@ -1591,24 +1918,30 @@ spring: close-notify-flush-timeout-millis: 3000 close-notify-read-timeout-millis: 0 ---- +==== == Configuration -Configuration for Spring Cloud Gateway is driven by a collection of ``RouteDefinitionLocator``s. +Configuration for Spring Cloud Gateway is driven by a collection of `RouteDefinitionLocator` instances. +The following listing shows the definition of the `RouteDefinitionLocator` interface: .RouteDefinitionLocator.java +==== [source,java] ---- public interface RouteDefinitionLocator { Flux getRouteDefinitions(); } ---- +==== -By default, a `PropertiesRouteDefinitionLocator` loads properties using Spring Boot's `@ConfigurationProperties` mechanism. +By default, a `PropertiesRouteDefinitionLocator` loads properties by using Spring Boot's `@ConfigurationProperties` mechanism. -The configuration examples above all use a shortcut notation that uses positional arguments rather than named ones. The two examples below are equivalent: +The earlier configuration examples all use a shortcut notation that uses positional arguments rather than named ones. +The following two examples are equivalent: .application.yml +==== [source,yaml] ---- spring: @@ -1626,13 +1959,16 @@ spring: filters: - SetStatus=401 ---- +==== -For some usages of the gateway, properties will be adequate, but some production use cases will benefit from loading configuration from an external source, such as a database. Future milestone versions will have `RouteDefinitionLocator` implementations based off of Spring Data Repositories such as: Redis, MongoDB and Cassandra. +For some usages of the gateway, properties are adequate, but some production use cases benefit from loading configuration from an external source, such as a database. Future milestone versions will have `RouteDefinitionLocator` implementations based off of Spring Data Repositories, such as Redis, MongoDB, and Cassandra. -== Route metadata configuration -Additional parameters can be configured for each route using metadata: +== Route Metadata Configuration + +You can configure additional parameters for each route by using metadata, as follows: .application.yml +==== [source,yaml] ---- spring: @@ -1647,15 +1983,20 @@ spring: name: "value" iAmNumber: 1 ---- +==== -All metadata properties could be acquired from exchange: -``` +You could acquire all metadata properties from an exchange, as follows: + +==== +[source] +---- Route route = exchange.getAttribute(GATEWAY_ROUTE_ATTR); // get all metadata properties route.getMetadata(); // get a single metadata property route.getMetadata(someKey); -``` +---- +==== == Http timeouts configuration @@ -1717,9 +2058,12 @@ import static org.springframework.cloud.gateway.support.RouteMetadataUtils.RESPO ---- === Fluent Java Routes API -To allow for simple configuration in Java, there is a fluent API defined in the `RouteLocatorBuilder` bean. + +To allow for simple configuration in Java, the `RouteLocatorBuilder` bean includes a fluent API. +The following listing shows how it works: .GatewaySampleApplication.java +==== [source,java] ---- // static imports from GatewayFilters and RoutePredicates @@ -1749,32 +2093,34 @@ public RouteLocator customRouteLocator(RouteLocatorBuilder builder, ThrottleGate .build(); } ---- +==== -This style also allows for more custom predicate assertions. The predicates defined by `RouteDefinitionLocator` beans are combined using logical `and`. By using the fluent Java API, you can use the `and()`, `or()` and `negate()` operators on the `Predicate` class. +This style also allows for more custom predicate assertions. +The predicates defined by `RouteDefinitionLocator` beans are combined using logical `and`. +By using the fluent Java API, you can use the `and()`, `or()`, and `negate()` operators on the `Predicate` class. -=== DiscoveryClient Route Definition Locator +=== The `DiscoveryClient` Route Definition Locator -The Gateway can be configured to create routes based on services registered with a `DiscoveryClient` compatible service registry. +You can configure the gateway to create routes based on services registered with a `DiscoveryClient` compatible service registry. -To enable this, set `spring.cloud.gateway.discovery.locator.enabled=true` and make sure a `DiscoveryClient` implementation is on the classpath and enabled (such as Netflix Eureka, Consul or Zookeeper). +To enable this, set `spring.cloud.gateway.discovery.locator.enabled=true` and make sure a `DiscoveryClient` implementation (such as Netflix Eureka, Consul, or Zookeeper) is on the classpath and enabled. -==== Configuring Predicates and Filters For DiscoveryClient Routes +==== Configuring Predicates and Filters For `DiscoveryClient` Routes -By default the Gateway defines a single predicate and filter for routes created via a `DiscoveryClient`. +By default, the fateway defines a single predicate and filter for routes created with a `DiscoveryClient`. The default predicate is a path predicate defined with the pattern `/serviceId/**`, where `serviceId` is -the id of the service from the `DiscoveryClient`. +the ID of the service from the `DiscoveryClient`. -The default filter is rewrite path filter with the regex `/serviceId/(?.*)` and the replacement -`/${remaining}`. This just strips the service id from the path before the request is sent -downstream. +The default filter is a rewrite path filter with the regex `/serviceId/(?.*)` and the replacement `/${remaining}`. +This strips the service ID from the path before the request is sent downstream. -If you would like to customize the predicates and/or filters used by the `DiscoveryClient` routes you can do so -by setting `spring.cloud.gateway.discovery.locator.predicates[x]` and `spring.cloud.gateway.discovery.locator.filters[y]`. -When doing so you need to make sure to include the default predicate and filter above, if you want to retain -that functionality. Below is an example of what this looks like. +If you want to customize the predicates or filters used by the `DiscoveryClient` routes, set `spring.cloud.gateway.discovery.locator.predicates[x]` and `spring.cloud.gateway.discovery.locator.filters[y]`. +When doing so, you need to make sure to include the default predicate and filter shown earlier, if you want to retain that functionality. +The following example shows what this looks like: .application.properties +==== [soure,properties] ---- spring.cloud.gateway.discovery.locator.predicates[0].name: Path @@ -1787,14 +2133,18 @@ spring.cloud.gateway.discovery.locator.filters[1].name: RewritePath spring.cloud.gateway.discovery.locator.filters[1].args[regexp]: "'/' + serviceId + '/(?.*)'" spring.cloud.gateway.discovery.locator.filters[1].args[replacement]: "'/${remaining}'" ---- +==== == Reactor Netty Access Logs -To enable Reactor Netty access logs, set `-Dreactor.netty.http.server.accessLogEnabled=true`. (It must be a Java System Property, not a Spring Boot property). +To enable Reactor Netty access logs, set `-Dreactor.netty.http.server.accessLogEnabled=true`. -The logging system can be configured to have a separate access log file. Below is an example logback configuration: +IMPORTANT: It must be a Java System Property, not a Spring Boot property. + +You can configure the logging system to have a separate access log file. The following example creates a Logback configuration: .logback.xml +==== [source,xml] ---- @@ -1811,12 +2161,15 @@ The logging system can be configured to have a separate access log file. Below i ---- +==== == CORS Configuration -The gateway can be configured to control CORS behavior. The "global" CORS configuration is a map of URL patterns to https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/cors/CorsConfiguration.html[Spring Framework `CorsConfiguration`]. +You can configure the gateway to control CORS behavior. The "`global`" CORS configuration is a map of URL patterns to https://docs.spring.io/spring/docs/5.0.x/javadoc-api/org/springframework/web/cors/CorsConfiguration.html[Spring Framework `CorsConfiguration`]. +The following example configures CORS: .application.yml +==== [source,yaml] ---- spring: @@ -1829,27 +2182,35 @@ spring: allowedMethods: - GET ---- +==== -In the example above, CORS requests will be allowed from requests that originate from docs.spring.io for all GET requested paths. +In the preceding example, CORS requests are allowed from requests that originate from `docs.spring.io` for all GET requested paths. -To provide the same CORS configuration to requests that are not handled by some gateway route predicate, set the property `spring.cloud.gateway.globalcors.add-to-simple-url-handler-mapping` equal to true. This is useful when trying to support CORS preflight requests and your route predicate doesn't evalute to true because the http method is `options`. +To provide the same CORS configuration to requests that are not handled by some gateway route predicate, set the `spring.cloud.gateway.globalcors.add-to-simple-url-handler-mapping` property to `true`. +This is useful when you try to support CORS preflight requests and your route predicate does not evalute to `true` because the HTTP method is `options`. == Actuator API -The `/gateway` actuator endpoint allows to monitor and interact with a Spring Cloud Gateway application. To be remotely accessible, the endpoint has to be https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html#production-ready-endpoints-enabling-endpoints[enabled] and https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html#production-ready-endpoints-exposing-endpoints[exposed via HTTP or JMX] in the application properties. +The `/gateway` actuator endpoint lets you monitor and interact with a Spring Cloud Gateway application. +To be remotely accessible, the endpoint has to be https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html#production-ready-endpoints-enabling-endpoints[enabled] and https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-endpoints.html#production-ready-endpoints-exposing-endpoints[exposed over HTTP or JMX] in the application properties. +The following listing shows how to do so: .application.properties +==== [source,properties] ---- management.endpoint.gateway.enabled=true # default value management.endpoints.web.exposure.include=gateway ---- +==== === Verbose Actuator Format -A new, more verbose format has been added to Gateway. This adds more detail to each route allowing to view the predicates and filters associated to each route along with any configuration that is available. +A new, more verbose format has been added to Spring Cloud Gateway. +It adds more detail to each route, letting you view the predicates and filters associated with each route along with any configuration that is available. +The following example configures `/actuator/gateway/routes`: -`/actuator/gateway/routes` +==== [source,json] ---- [ @@ -1866,21 +2227,33 @@ A new, more verbose format has been added to Gateway. This adds more detail to e } ] ---- +==== This feature is enabled by default. To disable it, set the following property: .application.properties +==== [source,properties] ---- spring.cloud.gateway.actuator.verbose.enabled=false ---- +==== -This will default to true in a future release. +This will default to `true` in a future release. -=== Retrieving route filters +=== Retrieving Route Filters + +This section details how to retrieve route filters, including: + +* <> +* <> + +[[gateway-global-filters]] ==== Global Filters + To retrieve the <> applied to all routes, make a `GET` request to `/actuator/gateway/globalfilters`. The resulting response is similar to the following: +==== ---- { "org.springframework.cloud.gateway.filter.LoadBalancerClientFilter@77856cc5": 10100, @@ -1893,12 +2266,17 @@ To retrieve the <> applied to all routes, make a "org.springframework.cloud.gateway.filter.WebsocketRoutingFilter@23c05889": 2147483646 } ---- +==== -The response contains details of the global filters in place. For each global filter is provided the string representation of the filter object (e.g., `org.springframework.cloud.gateway.filter.LoadBalancerClientFilter@77856cc5`) and the corresponding <> in the filter chain. +The response contains the details of the global filters that are in place. +For each global filter, there is a string representation of the filter object (for example, `org.springframework.cloud.gateway.filter.LoadBalancerClientFilter@77856cc5`) and the corresponding <> in the filter chain.} +[[gateway-route-filters]] ==== Route Filters -To retrieve the <> applied to routes, make a `GET` request to `/actuator/gateway/routefilters`. The resulting response is similar to the following: +To retrieve the <> applied to routes, make a `GET` request to `/actuator/gateway/routefilters`. +The resulting response is similar to the following: +==== ---- { "[AddRequestHeaderGatewayFilterFactory@570ed9c configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null, @@ -1906,15 +2284,23 @@ To retrieve the <> applied to r "[SaveSessionGatewayFilterFactory@4449b273 configClass = Object]": null } ---- +==== -The response contains details of the GatewayFilter factories applied to any particular route. For each factory is provided the string representation of the corresponding object (e.g., `[SecureHeadersGatewayFilterFactory@fceab5d configClass = Object]`). Note that the `null` value is due to an incomplete implementation of the endpoint controller, for that it tries to set the order of the object in the filter chain, which does not apply to a GatewayFilter factory object. +The response contains the details of the `GatewayFilter` factories applied to any particular route. +For each factory there is a string representation of the corresponding object (for example, `[SecureHeadersGatewayFilterFactory@fceab5d configClass = Object]`). +Note that the `null` value is due to an incomplete implementation of the endpoint controller, because it tries to set the order of the object in the filter chain, which does not apply to a `GatewayFilter` factory object. -=== Refreshing the route cache -To clear the routes cache, make a `POST` request to `/actuator/gateway/refresh`. The request returns a 200 without response body. +=== Refreshing the Route Cache -=== Retrieving the routes defined in the gateway -To retrieve the routes defined in the gateway, make a `GET` request to `/actuator/gateway/routes`. The resulting response is similar to the following: +To clear the routes cache, make a `POST` request to `/actuator/gateway/refresh`. +The request returns a 200 without a response body. +=== Retrieving the Routes Defined in the Gateway + +To retrieve the routes defined in the gateway, make a `GET` request to `/actuator/gateway/routes`. +The resulting response is similar to the following: + +==== ---- [{ "route_id": "first_route", @@ -1935,8 +2321,10 @@ To retrieve the routes defined in the gateway, make a `GET` request to `/actuato "order": 0 }] ---- +==== -The response contains details of all the routes defined in the gateway. The following table describes the structure of each element (i.e., a route) of the response. +The response contains the details of all the routes defined in the gateway. +The following table describes the structure of each element (each is a route) of the response: [cols="3,2,4"] |=== @@ -1944,7 +2332,7 @@ The response contains details of all the routes defined in the gateway. The foll |`route_id` | String -| The route id. +| The route ID. |`route_object.predicate` | Object @@ -1952,7 +2340,7 @@ The response contains details of all the routes defined in the gateway. The foll |`route_object.filters` | Array -| The <> applied to the route. +| The <> applied to the route. |`order` | Number @@ -1960,9 +2348,13 @@ The response contains details of all the routes defined in the gateway. The foll |=== -=== Retrieving information about a particular route -To retrieve information about a single route, make a `GET` request to `/actuator/gateway/routes/{id}` (e.g., `/actuator/gateway/routes/first_route`). The resulting response is similar to the following: +[[gateway-retrieving-information-about-a-particular-route]] +=== Retrieving Information about a Particular Route +To retrieve information about a single route, make a `GET` request to `/actuator/gateway/routes/{id}` (for example, `/actuator/gateway/routes/first_route`). +The resulting response is similar to the following: + +==== ---- { "id": "first_route", @@ -1975,8 +2367,9 @@ To retrieve information about a single route, make a `GET` request to `/actuator "order": 0 }] ---- +==== -The following table describes the structure of the response. +The following table describes the structure of the response: [cols="3,2,4"] |=== @@ -1984,7 +2377,7 @@ The following table describes the structure of the response. |`id` | String -| The route id. +| The route ID. |`predicates` | Array @@ -2004,13 +2397,15 @@ The following table describes the structure of the response. |=== -=== Creating and deleting a particular route -To create a route, make a `POST` request to `/gateway/routes/{id_route_to_create}` with a JSON body that specifies the fields of the route (see the previous subsection). +=== Creating and Deleting a Particular Route + +To create a route, make a `POST` request to `/gateway/routes/{id_route_to_create}` with a JSON body that specifies the fields of the route (see <>). To delete a route, make a `DELETE` request to `/gateway/routes/{id_route_to_delete}`. -=== Recap: list of all endpoints -The table below summarises the Spring Cloud Gateway actuator endpoints. Note that each endpoint has `/actuator/gateway` as the base-path. +=== Recap: The List of All endpoints + +The folloiwng table below summarizes the Spring Cloud Gateway actuator endpoints (note that each endpoint has `/actuator/gateway` as the base-path): [cols="2,2,5"] |=== @@ -2022,7 +2417,7 @@ The table below summarises the Spring Cloud Gateway actuator endpoints. Note tha |`routefilters` |GET -| Displays the list of GatewayFilter factories applied to a particular route. +| Displays the list of `GatewayFilter` factories applied to a particular route. |`refresh` |POST @@ -2038,20 +2433,22 @@ The table below summarises the Spring Cloud Gateway actuator endpoints. Note tha |`routes/{id}` |POST -| Add a new route to the gateway. +| Adds a new route to the gateway. |`routes/{id}` |DELETE -| Remove an existing route from the gateway. +| Removes an existing route from the gateway. |=== [[troubleshooting]] == Troubleshooting +This section covers common problems that may arise when you use Spring Cloud Gateway. + === Log Levels -Below are some useful loggers that contain valuable trouble shooting infomration at the `DEBUG` and `TRACE` levels. +The following loggers may contain valuable troubleshooting information at the `DEBUG` and `TRACE` levels: - `org.springframework.cloud.gateway` - `org.springframework.http.server.reactive` @@ -2062,12 +2459,9 @@ Below are some useful loggers that contain valuable trouble shooting infomration === Wiretap -The Reactor Netty `HttpClient` and `HttpServer` can have wiretap enabled. When combined -with setting the `reactor.netty` log level to `DEBUG` or `TRACE` will enable logging of -information such as headers and bodies sent and received across the wire. To enable this, -set `spring.cloud.gateway.httpserver.wiretap=true` and/or -`spring.cloud.gateway.httpclient.wiretap=true` for the `HttpServer` and `HttpClient` -respectively. +The Reactor Netty `HttpClient` and `HttpServer` can have wiretap enabled. +When combined with setting the `reactor.netty` log level to `DEBUG` or `TRACE`, it enables the logging of information, such as headers and bodies sent and received across the wire. +To enable wiretap, set `spring.cloud.gateway.httpserver.wiretap=true` or `spring.cloud.gateway.httpclient.wiretap=true` for the `HttpServer` and `HttpClient`, respectively. == Developer Guide @@ -2079,9 +2473,12 @@ TODO: document writing Custom Route Predicate Factories === Writing Custom GatewayFilter Factories -In order to write a GatewayFilter you will need to implement `GatewayFilterFactory`. There is an abstract class called `AbstractGatewayFilterFactory` which you can extend. +To write a `GatewayFilter`, you must implement `GatewayFilterFactory`. +You can extend an abstract class called `AbstractGatewayFilterFactory`. +The following examples show how to do so: .PreGatewayFilterFactory.java +==== [source,java] ---- public class PreGatewayFilterFactory extends AbstractGatewayFilterFactory { @@ -2135,13 +2532,16 @@ public class PostGatewayFilterFactory extends AbstractGatewayFilterFactory proxyPath(ProxyExchange proxy) throws Exception { String path = proxy.path("/proxy/path/"); return proxy.uri(home.toString() + "/foos/" + path).get(); } -``` +---- +==== -All the features of Spring MVC or Webflux are available to Gateway handler methods. So you can inject request headers and query parameters, for instance, and you can constrain the incoming requests with declarations in the mapping annotation. See the documentation for `@RequestMapping` in Spring MVC for more details of those features. +All the features of Spring MVC and Webflux are available to gateway handler methods. +As a result, you can inject request headers and query parameters, for instance, and you can constrain the incoming requests with declarations in the mapping annotation. +See the documentation for `@RequestMapping` in Spring MVC for more details of those features. -Headers can be added to the downstream response using the `header()` methods on `ProxyExchange`. +You can add headers to the downstream response by using the `header()` methods on `ProxyExchange`. -You can also manipulate response headers (and anything else you like in the response) by adding a mapper to the `get()` etc. method. The mapper is a `Function` that takes the incoming `ResponseEntity` and converts it to an outgoing one. +You can also manipulate response headers (and anything else you like in the response) by adding a mapper to the `get()` method (and other methods). +The mapper is a `Function` that takes the incoming `ResponseEntity` and converts it to an outgoing one. -First class support is provided for "sensitive" headers ("cookie" and "authorization" by default) which are not passed downstream, and for "proxy" headers (`x-forwarded-*`). +First-class support is provided for "`sensitive`" headers (by default, `cookie` and `authorization`), which are not passed downstream, and for "`proxy`" (`x-forwarded-*`) headers. == Configuration properties -To see the list of all Spring Cloud Gateway related configuration properties please check link:appendix.html[the Appendix page]. +To see the list of all Spring Cloud Gateway related configuration properties, see link:appendix.html[the appendix].