Migrate Structure
This commit is contained in:
Marcin Grzejszczak
16
docs/modules/ROOT/pages/README.adoc
Normal file
16
docs/modules/ROOT/pages/README.adoc
Normal file
@@ -0,0 +1,16 @@
|
||||
= Spring Cloud Bus
|
||||
include::_attributes.adoc[]
|
||||
|
||||
include::intro.adoc[]
|
||||
|
||||
== Quick Start
|
||||
|
||||
include::quickstart.adoc[]
|
||||
|
||||
== Building
|
||||
|
||||
include::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/docs/src/main/asciidoc/building.adoc[]
|
||||
|
||||
== Contributing
|
||||
|
||||
include::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/docs/src/main/asciidoc/contributing.adoc[]
|
||||
15
docs/modules/ROOT/pages/_attributes.adoc
Normal file
15
docs/modules/ROOT/pages/_attributes.adoc
Normal file
@@ -0,0 +1,15 @@
|
||||
:doctype: book
|
||||
:idprefix:
|
||||
:idseparator: -
|
||||
:toc: left
|
||||
:toclevels: 4
|
||||
:tabsize: 4
|
||||
:numbered:
|
||||
:sectanchors:
|
||||
:sectnums:
|
||||
:icons: font
|
||||
:hide-uri-scheme:
|
||||
:docinfo: shared,private
|
||||
|
||||
:sc-ext: java
|
||||
:project-full-name: Spring Cloud Bus
|
||||
14
docs/modules/ROOT/pages/_configprops.adoc
Normal file
14
docs/modules/ROOT/pages/_configprops.adoc
Normal file
@@ -0,0 +1,14 @@
|
||||
|===
|
||||
|Name | Default | Description
|
||||
|
||||
|spring.cloud.bus.ack.destination-service | | Service that wants to listen to acks. By default null (meaning all services).
|
||||
|spring.cloud.bus.ack.enabled | `+++true+++` | Flag to switch off acks (default on).
|
||||
|spring.cloud.bus.content-type | | The bus mime-type.
|
||||
|spring.cloud.bus.destination | | Name of Spring Cloud Stream destination for messages.
|
||||
|spring.cloud.bus.enabled | `+++true+++` | Flag to indicate that the bus is enabled.
|
||||
|spring.cloud.bus.env.enabled | `+++true+++` | Flag to switch off environment change events (default on).
|
||||
|spring.cloud.bus.id | `+++application+++` | The identifier for this application instance.
|
||||
|spring.cloud.bus.refresh.enabled | `+++true+++` | Flag to switch off refresh events (default on).
|
||||
|spring.cloud.bus.trace.enabled | `+++false+++` | Flag to switch on tracing of acks (default off).
|
||||
|
||||
|===
|
||||
14
docs/modules/ROOT/pages/appendix.adoc
Normal file
14
docs/modules/ROOT/pages/appendix.adoc
Normal file
@@ -0,0 +1,14 @@
|
||||
:numbered!:
|
||||
[appendix]
|
||||
[[common-application-properties]]
|
||||
== Common application properties
|
||||
|
||||
include::_attributes.adoc[]
|
||||
|
||||
Various properties can be specified inside your `application.properties` file, inside your `application.yml` file, or as command line switches.
|
||||
This appendix provides a list of common {project-full-name} properties and references to the underlying classes that consume them.
|
||||
|
||||
NOTE: Property contributions can come from additional jar files on your classpath, so you should not consider this an exhaustive list.
|
||||
Also, you can define your own properties.
|
||||
|
||||
include::_configprops.adoc[]
|
||||
1
docs/modules/ROOT/pages/index.adoc
Executable file
1
docs/modules/ROOT/pages/index.adoc
Executable file
@@ -0,0 +1 @@
|
||||
include::spring-cloud-bus.adoc[]
|
||||
6
docs/modules/ROOT/pages/intro.adoc
Normal file
6
docs/modules/ROOT/pages/intro.adoc
Normal file
@@ -0,0 +1,6 @@
|
||||
Spring Cloud Bus links the nodes of a distributed system with a lightweight message
|
||||
broker. This broker can then be used to broadcast state changes (such as configuration
|
||||
changes) or other management instructions. A key idea is that the bus is like a
|
||||
distributed actuator for a Spring Boot application that is scaled out. However, it can
|
||||
also be used as a communication channel between apps. This project provides starters for
|
||||
either an AMQP broker or Kafka as the transport.
|
||||
28
docs/modules/ROOT/pages/quickstart.adoc
Normal file
28
docs/modules/ROOT/pages/quickstart.adoc
Normal file
@@ -0,0 +1,28 @@
|
||||
Spring Cloud Bus works by adding Spring Boot autconfiguration if it detects itself on the
|
||||
classpath. To enable the bus, add `spring-cloud-starter-bus-amqp` or
|
||||
`spring-cloud-starter-bus-kafka` to your dependency management. Spring Cloud takes care of
|
||||
the rest. Make sure the broker (RabbitMQ or Kafka) is available and configured. When
|
||||
running on localhost, you need not do anything. If you run remotely, use Spring Cloud
|
||||
Connectors or Spring Boot conventions to define the broker credentials, as shown in the
|
||||
following example for Rabbit:
|
||||
|
||||
.application.yml
|
||||
----
|
||||
spring:
|
||||
rabbitmq:
|
||||
host: mybroker.com
|
||||
port: 5672
|
||||
username: user
|
||||
password: secret
|
||||
----
|
||||
|
||||
The bus currently supports sending messages to all nodes listening or all nodes for a
|
||||
particular service (as defined by Eureka). The `/bus/*` actuator namespace has some HTTP
|
||||
endpoints. Currently, two are implemented. The first, `/bus/env`, sends key/value pairs to
|
||||
update each node's Spring Environment. The second, `/bus/refresh`, reloads each
|
||||
application's configuration, as though they had all been pinged on their `/refresh`
|
||||
endpoint.
|
||||
|
||||
NOTE: The Spring Cloud Bus starters cover Rabbit and Kafka, because those are the two most
|
||||
common implementations. However, Spring Cloud Stream is quite flexible, and the binder
|
||||
works with `spring-cloud-bus`.
|
||||
26
docs/modules/ROOT/pages/sagan-index.adoc
Normal file
26
docs/modules/ROOT/pages/sagan-index.adoc
Normal file
@@ -0,0 +1,26 @@
|
||||
|
||||
Spring Cloud Bus links nodes of a distributed system with a lightweight message broker. This can then be used to broadcast state changes (e.g. configuration changes) or other management instructions. AMQP and Kafka broker implementations are included with the project. Alternatively, any link:https://spring.io/projects/spring-cloud-stream[Spring Cloud Stream] binder found on the classpath will work out of the box as a transport.
|
||||
|
||||
## Getting Started
|
||||
As long as Spring Cloud Bus AMQP and RabbitMQ are on the
|
||||
classpath any Spring Boot application will try to contact a RabbitMQ
|
||||
server on `localhost:5672` (the default value of
|
||||
`spring.rabbitmq.addresses`):
|
||||
|
||||
```java
|
||||
@Configuration
|
||||
@EnableAutoConfiguration
|
||||
@RestController
|
||||
public class Application {
|
||||
|
||||
@RequestMapping("/")
|
||||
public String home() {
|
||||
return "Hello World";
|
||||
}
|
||||
|
||||
public static void main(String[] args) {
|
||||
SpringApplication.run(Application.class, args);
|
||||
}
|
||||
|
||||
}
|
||||
```
|
||||
231
docs/modules/ROOT/pages/spring-cloud-bus.adoc
Normal file
231
docs/modules/ROOT/pages/spring-cloud-bus.adoc
Normal file
@@ -0,0 +1,231 @@
|
||||
= Spring Cloud Bus
|
||||
include::_attributes.adoc[]
|
||||
|
||||
include::intro.adoc[]
|
||||
|
||||
include::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/docs/src/main/asciidoc/contributing-docs.adoc[]
|
||||
|
||||
== Quick Start
|
||||
|
||||
include::quickstart.adoc[]
|
||||
|
||||
== Bus Endpoints
|
||||
|
||||
Spring Cloud Bus provides two endpoints, `/actuator/busrefresh` and `/actuator/busenv`
|
||||
that correspond to individual actuator endpoints in Spring Cloud Commons,
|
||||
`/actuator/refresh` and `/actuator/env` respectively.
|
||||
|
||||
=== Bus Refresh Endpoint
|
||||
The `/actuator/busrefresh` endpoint clears the `RefreshScope` cache and rebinds
|
||||
`@ConfigurationProperties`. See the <<refresh-scope,Refresh Scope>> documentation for
|
||||
more information.
|
||||
|
||||
To expose the `/actuator/busrefresh` endpoint, you need to add following configuration to your
|
||||
application:
|
||||
|
||||
[source,properties]
|
||||
----
|
||||
management.endpoints.web.exposure.include=busrefresh
|
||||
----
|
||||
|
||||
=== Bus Env Endpoint
|
||||
The `/actuator/busenv` endpoint updates each instances environment with the specified
|
||||
key/value pair across multiple instances.
|
||||
|
||||
To expose the `/actuator/busenv` endpoint, you need to add following configuration to your
|
||||
application:
|
||||
|
||||
[source,properties]
|
||||
----
|
||||
management.endpoints.web.exposure.include=busenv
|
||||
----
|
||||
|
||||
The `/actuator/busenv` endpoint accepts `POST` requests with the following shape:
|
||||
|
||||
[source,json]
|
||||
----
|
||||
{
|
||||
"name": "key1",
|
||||
"value": "value1"
|
||||
}
|
||||
----
|
||||
|
||||
== Addressing an Instance
|
||||
|
||||
Each instance of the application has a service ID, whose value can be set with
|
||||
`spring.cloud.bus.id` and whose value is expected to be a colon-separated list of
|
||||
identifiers, in order from least specific to most specific. The default value is
|
||||
constructed from the environment as a combination of the `spring.application.name` and
|
||||
`server.port` (or `spring.application.index`, if set). The default value of the ID is
|
||||
constructed in the form of `app:index:id`, where:
|
||||
|
||||
* `app` is the `vcap.application.name`, if it exists, or `spring.application.name`
|
||||
* `index` is the `vcap.application.instance_index`, if it exists,
|
||||
`spring.application.index`, `local.server.port`, `server.port`, or `0` (in that order).
|
||||
* `id` is the `vcap.application.instance_id`, if it exists, or a random value.
|
||||
|
||||
The HTTP endpoints accept a "`destination`" path parameter, such as
|
||||
`/busrefresh/customers:9000`, where `destination` is a service ID. If the ID
|
||||
is owned by an instance on the bus, it processes the message, and all other instances
|
||||
ignore it.
|
||||
|
||||
== Addressing All Instances of a Service
|
||||
|
||||
The "`destination`" parameter is used in a Spring `PathMatcher` (with the path separator
|
||||
as a colon -- `:`) to determine if an instance processes the message. Using the example
|
||||
from earlier, `/busenv/customers:**` targets all instances of the
|
||||
"`customers`" service regardless of the rest of the service ID.
|
||||
|
||||
== Service ID Must Be Unique
|
||||
|
||||
The bus tries twice to eliminate processing an event -- once from the original
|
||||
`ApplicationEvent` and once from the queue. To do so, it checks the sending service ID
|
||||
against the current service ID. If multiple instances of a service have the same ID,
|
||||
events are not processed. When running on a local machine, each service is on a different
|
||||
port, and that port is part of the ID. Cloud Foundry supplies an index to differentiate.
|
||||
To ensure that the ID is unique outside Cloud Foundry, set `spring.application.index` to
|
||||
something unique for each instance of a service.
|
||||
|
||||
== Customizing the Message Broker
|
||||
|
||||
Spring Cloud Bus uses https://cloud.spring.io/spring-cloud-stream[Spring Cloud Stream] to
|
||||
broadcast the messages. So, to get messages to flow, you need only include the binder
|
||||
implementation of your choice in the classpath. There are convenient starters for the bus
|
||||
with AMQP (RabbitMQ) and Kafka (`spring-cloud-starter-bus-[amqp|kafka]`). Generally
|
||||
speaking, Spring Cloud Stream relies on Spring Boot autoconfiguration conventions for
|
||||
configuring middleware. For instance, the AMQP broker address can be changed with
|
||||
`spring.rabbitmq.{asterisk}` configuration properties. Spring Cloud Bus has a handful of
|
||||
native configuration properties in `spring.cloud.bus.{asterisk}` (for example,
|
||||
`spring.cloud.bus.destination` is the name of the topic to use as the external
|
||||
middleware). Normally, the defaults suffice.
|
||||
|
||||
To learn more about how to customize the message broker settings, consult the Spring Cloud
|
||||
Stream documentation.
|
||||
|
||||
== Tracing Bus Events
|
||||
|
||||
Bus events (subclasses of `RemoteApplicationEvent`) can be traced by setting
|
||||
`spring.cloud.bus.trace.enabled=true`. If you do so, the Spring Boot `TraceRepository`
|
||||
(if it is present) shows each event sent and all the acks from each service instance. The
|
||||
following example comes from the `/trace` endpoint:
|
||||
|
||||
[source,json]
|
||||
----
|
||||
{
|
||||
"timestamp": "2015-11-26T10:24:44.411+0000",
|
||||
"info": {
|
||||
"signal": "spring.cloud.bus.ack",
|
||||
"type": "RefreshRemoteApplicationEvent",
|
||||
"id": "c4d374b7-58ea-4928-a312-31984def293b",
|
||||
"origin": "stores:8081",
|
||||
"destination": "*:**"
|
||||
}
|
||||
},
|
||||
{
|
||||
"timestamp": "2015-11-26T10:24:41.864+0000",
|
||||
"info": {
|
||||
"signal": "spring.cloud.bus.sent",
|
||||
"type": "RefreshRemoteApplicationEvent",
|
||||
"id": "c4d374b7-58ea-4928-a312-31984def293b",
|
||||
"origin": "customers:9000",
|
||||
"destination": "*:**"
|
||||
}
|
||||
},
|
||||
{
|
||||
"timestamp": "2015-11-26T10:24:41.862+0000",
|
||||
"info": {
|
||||
"signal": "spring.cloud.bus.ack",
|
||||
"type": "RefreshRemoteApplicationEvent",
|
||||
"id": "c4d374b7-58ea-4928-a312-31984def293b",
|
||||
"origin": "customers:9000",
|
||||
"destination": "*:**"
|
||||
}
|
||||
}
|
||||
----
|
||||
|
||||
The preceding trace shows that a `RefreshRemoteApplicationEvent` was sent from
|
||||
`customers:9000`, broadcast to all services, and received (acked) by `customers:9000` and
|
||||
`stores:8081`.
|
||||
|
||||
To handle the ack signals yourself, you could add an `@EventListener` for the
|
||||
`AckRemoteApplicationEvent` and `SentApplicationEvent` types to your app (and enable
|
||||
tracing). Alternatively, you could tap into the `TraceRepository` and mine the data from
|
||||
there.
|
||||
|
||||
NOTE: Any Bus application can trace acks. However, sometimes, it is
|
||||
useful to do this in a central service that can do more complex
|
||||
queries on the data or forward it to a specialized tracing service.
|
||||
|
||||
== Broadcasting Your Own Events
|
||||
|
||||
The Bus can carry any event of type `RemoteApplicationEvent`. The default transport is
|
||||
JSON, and the deserializer needs to know which types are going to be used ahead of time.
|
||||
To register a new type, you must put it in a subpackage of
|
||||
`org.springframework.cloud.bus.event`.
|
||||
|
||||
To customise the event name, you can use `@JsonTypeName` on your custom class or rely on
|
||||
the default strategy, which is to use the simple name of the class.
|
||||
|
||||
NOTE: Both the producer and the consumer need access to the class definition.
|
||||
|
||||
=== Registering events in custom packages
|
||||
|
||||
If you cannot or do not want to use a subpackage of `org.springframework.cloud.bus.event`
|
||||
for your custom events, you must specify which packages to scan for events of type
|
||||
`RemoteApplicationEvent` by using the `@RemoteApplicationEventScan` annotation. Packages
|
||||
specified with `@RemoteApplicationEventScan` include subpackages.
|
||||
|
||||
For example, consider the following custom event, called `MyEvent`:
|
||||
|
||||
[source,java]
|
||||
----
|
||||
package com.acme;
|
||||
|
||||
public class MyEvent extends RemoteApplicationEvent {
|
||||
...
|
||||
}
|
||||
----
|
||||
|
||||
You can register that event with the deserializer in the following way:
|
||||
|
||||
[source,java]
|
||||
----
|
||||
package com.acme;
|
||||
|
||||
@Configuration
|
||||
@RemoteApplicationEventScan
|
||||
public class BusConfiguration {
|
||||
...
|
||||
}
|
||||
----
|
||||
|
||||
Without specifying a value, the package of the class where `@RemoteApplicationEventScan`
|
||||
is used is registered. In this example, `com.acme` is registered by using the package of
|
||||
`BusConfiguration`.
|
||||
|
||||
You can also explicitly specify the packages to scan by using the `value`, `basePackages`
|
||||
or `basePackageClasses` properties on `@RemoteApplicationEventScan`, as shown in the
|
||||
following example:
|
||||
|
||||
[source,java]
|
||||
----
|
||||
package com.acme;
|
||||
|
||||
@Configuration
|
||||
//@RemoteApplicationEventScan({"com.acme", "foo.bar"})
|
||||
//@RemoteApplicationEventScan(basePackages = {"com.acme", "foo.bar", "fizz.buzz"})
|
||||
@RemoteApplicationEventScan(basePackageClasses = BusConfiguration.class)
|
||||
public class BusConfiguration {
|
||||
...
|
||||
}
|
||||
----
|
||||
|
||||
All of the preceding examples of `@RemoteApplicationEventScan` are equivalent, in that the
|
||||
`com.acme` package is registered by explicitly specifying the packages on
|
||||
`@RemoteApplicationEventScan`.
|
||||
|
||||
NOTE: You can specify multiple base packages to scan.
|
||||
|
||||
== Configuration properties
|
||||
|
||||
To see the list of all Bus related configuration properties please check link:appendix.html[the Appendix page].
|
||||
Reference in New Issue
Block a user