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Backport support for custom HTTP status in a backwards compatible way. (#1087)

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This commit is contained in:
Olga Maciaszek-Sharma
2022-03-29 16:47:35 +02:00
committed by GitHub
parent 395386414d
commit c72f6d0795
7 changed files with 133 additions and 17 deletions
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1
docs/src/main/asciidoc/_configprops.adoc
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@@ -57,6 +57,7 @@
|spring.cloud.loadbalancer.sticky-session | | Properties for LoadBalancer sticky-session.
|spring.cloud.loadbalancer.sticky-session.add-service-instance-cookie | `false` | Indicates whether a cookie with the newly selected instance should be added by LoadBalancer.
|spring.cloud.loadbalancer.sticky-session.instance-id-cookie-name | `sc-lb-instance-id` | The name of the cookie holding the preferred instance id.
|spring.cloud.loadbalancer.use-raw-status-code-in-response-data | `false` | Indicates that raw status codes should be used in {@link ResponseData}.
|spring.cloud.loadbalancer.x-forwarded | | Enabling X-Forwarded Host and Proto Headers.
|spring.cloud.loadbalancer.x-forwarded.enabled | `false` | To Enable X-Forwarded Headers.
|spring.cloud.loadbalancer.zone | | Spring Cloud LoadBalancer zone.

16
docs/src/main/asciidoc/spring-cloud-commons.adoc
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@@ -1218,20 +1218,28 @@ One type of bean that it may be useful to register using <<custom-loadbalancer-c
The `LoadBalancerLifecycle` beans provide callback methods, named `onStart(Request<RC> request)`, `onStartRequest(Request<RC> request, Response<T> lbResponse)` and `onComplete(CompletionContext<RES, T, RC> completionContext)`, that you should implement to specify what actions should take place before and after load-balancing.
`onStart(Request<RC> request)` takes a `Request` object as a parameter. It contains data that is used to select an appropriate instance, including the downstream client request and <<spring-cloud-loadbalancer-hints,hint>>. `onStartRequest` also takes the `Request` object and, additionally, the `Response<T>` object as parameters. On the other hand, a `CompletionContext` object is provided to the `onComplete(CompletionContext<RES, T, RC> completionContext)` method. It contains the LoadBalancer `Response`, including the selected service instance, the `Status` of the request executed against that service instance and (if available) the response returned to the downstream client, and (if an exception has occurred) the corresponding `Throwable`.
`onStart(Request<RC> request)` takes a `Request` object as a parameter.
It contains data that is used to select an appropriate instance, including the downstream client request and <<spring-cloud-loadbalancer-hints,hint>>. `onStartRequest` also takes the `Request` object and, additionally, the `Response<T>` object as parameters.
On the other hand, a `CompletionContext` object is provided to the `onComplete(CompletionContext<RES, T, RC> completionContext)` method.
It contains the LoadBalancer `Response`, including the selected service instance, the `Status` of the request executed against that service instance and (if available) the response returned to the downstream client, and (if an exception has occurred) the corresponding `Throwable`.
The `supports(Class requestContextClass, Class responseClass,
Class serverTypeClass)` method can be used to determine whether the processor in question handles objects of provided types. If not overridden by the user, it returns `true`.
Class serverTypeClass)` method can be used to determine whether the processor in question handles objects of provided types.
If not overridden by the user, it returns `true`.
NOTE: In the preceding method calls, `RC` means `RequestContext` type, `RES` means client response type, and `T` means returned server type.
WARNING: If you are using custom HTTP status codes, you will be getting exceptions.
In order to prevent this, you can set the value of `spring.cloud.loadbalancer.use-raw-status-code-in-response-data`.
It will cause raw status codes to be used instead of `HttpStatus` enums.
The `httpStatus` field in `ResponseData` will then be used, but you'll be able to get the raw status code from the `rawHttpStatus` field.
[[loadbalancer-micrometer-stats-lifecycle]]
=== Spring Cloud LoadBalancer Statistics
We provide a `LoadBalancerLifecycle` bean called `MicrometerStatsLoadBalancerLifecycle`, which uses Micrometer to provide statistics for load-balanced calls.
In order to get this bean added to your application context,
set the value of the `spring.cloud.loadbalancer.stats.micrometer.enabled` to `true` and have a `MeterRegistry` available (for example, by adding https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-features.html[Spring Boot Actuator] to your project).
In order to get this bean added to your application context, set the value of the `spring.cloud.loadbalancer.stats.micrometer.enabled` to `true` and have a `MeterRegistry` available (for example, by adding https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-features.html[Spring Boot Actuator] to your project).
`MicrometerStatsLoadBalancerLifecycle` registers the following meters in `MeterRegistry`:

13
spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerProperties.java
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@@ -68,6 +68,11 @@ public class LoadBalancerProperties {
*/
private StickySession stickySession = new StickySession();
/**
* Indicates that raw status codes should be used in {@link ResponseData}.
*/
private boolean useRawStatusCodeInResponseData;
public HealthCheck getHealthCheck() {
return healthCheck;
}
@@ -121,6 +126,14 @@ public class LoadBalancerProperties {
return xForwarded;
}
public boolean isUseRawStatusCodeInResponseData() {
return useRawStatusCodeInResponseData;
}
public void setUseRawStatusCodeInResponseData(boolean useRawStatusCodeInResponseData) {
this.useRawStatusCodeInResponseData = useRawStatusCodeInResponseData;
}
public static class StickySession {
/**

81
spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/ResponseData.java
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@@ -48,27 +48,93 @@ public class ResponseData {
private final RequestData requestData;
public ResponseData(HttpStatus httpStatus, HttpHeaders headers, MultiValueMap<String, ResponseCookie> cookies,
RequestData requestData) {
this.httpStatus = httpStatus;
private final Integer rawHttpStatus;
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(HttpHeaders headers, MultiValueMap<String, ResponseCookie> cookies, RequestData requestData,
Integer rawHttpStatus) {
this.httpStatus = null;
this.rawHttpStatus = rawHttpStatus;
this.headers = headers;
this.cookies = cookies;
this.requestData = requestData;
}
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(HttpStatus httpStatus, HttpHeaders headers, MultiValueMap<String, ResponseCookie> cookies,
RequestData requestData) {
this.httpStatus = httpStatus;
this.rawHttpStatus = httpStatus != null ? httpStatus.value() : null;
this.headers = headers;
this.cookies = cookies;
this.requestData = requestData;
}
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(ClientResponse response, RequestData requestData) {
this(response.statusCode(), response.headers().asHttpHeaders(), response.cookies(), requestData);
}
// Done this way to maintain backwards compatibility while allowing switching to raw
// HTTPStatus
// Will be removed in `4.x`
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(RequestData requestData, ClientResponse response) {
this(response.headers().asHttpHeaders(), response.cookies(), requestData, response.rawStatusCode());
}
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(ServerHttpResponse response, RequestData requestData) {
this(response.getStatusCode(), response.getHeaders(), response.getCookies(), requestData);
}
// Done this way to maintain backwards compatibility while allowing switching to raw
// HTTPStatus
// Will be removed in `4.x`
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(RequestData requestData, ServerHttpResponse response) {
this(response.getHeaders(), response.getCookies(), requestData, response.getRawStatusCode());
}
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(ClientHttpResponse clientHttpResponse, RequestData requestData) throws IOException {
this(clientHttpResponse.getStatusCode(), clientHttpResponse.getHeaders(),
buildCookiesFromHeaders(clientHttpResponse.getHeaders()), requestData);
}
// Done this way to maintain backwards compatibility while allowing switching to raw
// HTTPStatus
// Will be removed in `4.x`
/**
* @deprecated for removal; new constructors will be added in 4.x
*/
@Deprecated
public ResponseData(RequestData requestData, ClientHttpResponse clientHttpResponse) throws IOException {
this(clientHttpResponse.getHeaders(), buildCookiesFromHeaders(clientHttpResponse.getHeaders()), requestData,
clientHttpResponse.getRawStatusCode());
}
public HttpStatus getHttpStatus() {
return httpStatus;
}
@@ -85,6 +151,10 @@ public class ResponseData {
return requestData;
}
public Integer getRawHttpStatus() {
return rawHttpStatus;
}
@Override
public String toString() {
ToStringCreator to = new ToStringCreator(this);
@@ -113,7 +183,7 @@ public class ResponseData {
@Override
public int hashCode() {
return Objects.hash(httpStatus, headers, cookies, requestData);
return Objects.hash(httpStatus, headers, cookies, requestData, rawHttpStatus);
}
@Override
@@ -126,7 +196,8 @@ public class ResponseData {
}
ResponseData that = (ResponseData) o;
return httpStatus == that.httpStatus && Objects.equals(headers, that.headers)
&& Objects.equals(cookies, that.cookies) && Objects.equals(requestData, that.requestData);
&& Objects.equals(cookies, that.cookies) && Objects.equals(requestData, that.requestData)
&& Objects.equals(rawHttpStatus, that.rawHttpStatus);
}
}

15
spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/reactive/ReactorLoadBalancerExchangeFilterFunction.java
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@@ -128,8 +128,8 @@ public class ReactorLoadBalancerExchangeFilterFunction implements LoadBalancedEx
LOG.debug(String.format("LoadBalancer has retrieved the instance for service %s: %s", serviceId,
instance.getUri()));
}
LoadBalancerProperties.StickySession stickySessionProperties = loadBalancerFactory.getProperties(serviceId)
.getStickySession();
LoadBalancerProperties properties = loadBalancerFactory.getProperties(serviceId);
LoadBalancerProperties.StickySession stickySessionProperties = properties.getStickySession();
ClientRequest newRequest = buildClientRequest(clientRequest, instance,
stickySessionProperties.getInstanceIdCookieName(),
stickySessionProperties.isAddServiceInstanceCookie(), transformers);
@@ -140,10 +140,19 @@ public class ReactorLoadBalancerExchangeFilterFunction implements LoadBalancedEx
CompletionContext.Status.FAILED, throwable, lbRequest, lbResponse))))
.doOnSuccess(clientResponse -> supportedLifecycleProcessors.forEach(
lifecycle -> lifecycle.onComplete(new CompletionContext<>(CompletionContext.Status.SUCCESS,
lbRequest, lbResponse, new ResponseData(clientResponse, requestData)))));
lbRequest, lbResponse, buildResponseData(requestData, clientResponse,
properties.isUseRawStatusCodeInResponseData())))));
});
}
private ResponseData buildResponseData(RequestData requestData, ClientResponse clientResponse,
boolean useRawStatusCodes) {
if (useRawStatusCodes) {
return new ResponseData(requestData, clientResponse);
}
return new ResponseData(clientResponse, requestData);
}
protected Mono<Response<ServiceInstance>> choose(String serviceId, Request<RequestDataContext> request) {
ReactiveLoadBalancer<ServiceInstance> loadBalancer = loadBalancerFactory.getInstance(serviceId);
if (loadBalancer == null) {

16
spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/reactive/RetryableLoadBalancerExchangeFilterFunction.java
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@@ -164,9 +164,11 @@ public class RetryableLoadBalancerExchangeFilterFunction implements LoadBalanced
.doOnError(throwable -> supportedLifecycleProcessors.forEach(lifecycle -> lifecycle
.onComplete(new CompletionContext<ResponseData, ServiceInstance, RetryableRequestContext>(
CompletionContext.Status.FAILED, throwable, lbRequest, lbResponse))))
.doOnSuccess(clientResponse -> supportedLifecycleProcessors.forEach(
lifecycle -> lifecycle.onComplete(new CompletionContext<>(CompletionContext.Status.SUCCESS,
lbRequest, lbResponse, new ResponseData(clientResponse, requestData)))))
.doOnSuccess(
clientResponse -> supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onComplete(
new CompletionContext<>(CompletionContext.Status.SUCCESS, lbRequest, lbResponse,
buildResponseData(requestData, clientResponse,
properties.isUseRawStatusCodeInResponseData())))))
.map(clientResponse -> {
loadBalancerRetryContext.setClientResponse(clientResponse);
if (shouldRetrySameServiceInstance(retryPolicy, loadBalancerRetryContext)) {
@@ -192,6 +194,14 @@ public class RetryableLoadBalancerExchangeFilterFunction implements LoadBalanced
}).retryWhen(exchangeRetry)).retryWhen(filterRetry);
}
private ResponseData buildResponseData(RequestData requestData, ClientResponse clientResponse,
boolean useRawStatusCodes) {
if (useRawStatusCodes) {
return new ResponseData(requestData, clientResponse);
}
return new ResponseData(clientResponse, requestData);
}
private Retry buildRetrySpec(int max, boolean transientErrors, LoadBalancerProperties.Retry retry) {
if (!retry.isEnabled()) {
return Retry.max(0).filter(this::isRetryException).transientErrors(transientErrors);

8
spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/blocking/client/BlockingLoadBalancerClient.java
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@@ -96,7 +96,8 @@ public class BlockingLoadBalancerClient implements LoadBalancerClient {
.forEach(lifecycle -> lifecycle.onStartRequest(lbRequest, new DefaultResponse(serviceInstance)));
try {
T response = request.apply(serviceInstance);
Object clientResponse = getClientResponse(response);
LoadBalancerProperties properties = loadBalancerClientFactory.getProperties(serviceId);
Object clientResponse = getClientResponse(response, properties.isUseRawStatusCodeInResponseData());
supportedLifecycleProcessors
.forEach(lifecycle -> lifecycle.onComplete(new CompletionContext<>(CompletionContext.Status.SUCCESS,
lbRequest, defaultResponse, clientResponse)));
@@ -115,13 +116,16 @@ public class BlockingLoadBalancerClient implements LoadBalancerClient {
return null;
}
private <T> Object getClientResponse(T response) {
private <T> Object getClientResponse(T response, boolean useRawStatusCodes) {
ClientHttpResponse clientHttpResponse = null;
if (response instanceof ClientHttpResponse) {
clientHttpResponse = (ClientHttpResponse) response;
}
if (clientHttpResponse != null) {
try {
if (useRawStatusCodes) {
return new ResponseData(null, clientHttpResponse);
}
return new ResponseData(clientHttpResponse, null);
}
catch (IOException ignored) {