Package io.servicetalk.grpc.netty

Class GrpcLifecycleObserverRequesterFilter

java.lang.Object

io.servicetalk.http.netty.HttpLifecycleObserverRequesterFilter

io.servicetalk.grpc.netty.GrpcLifecycleObserverRequesterFilter

All Implemented Interfaces:

HttpExecutionStrategyInfluencer, StreamingHttpClientFilterFactory, StreamingHttpConnectionFilterFactory, ExecutionStrategyInfluencer<HttpExecutionStrategy>

public final class GrpcLifecycleObserverRequesterFilter
extends HttpLifecycleObserverRequesterFilter

An HTTP requester filter that tracks events during gRPC request/response lifecycle.

The result of the observed behavior will depend on the position of this filter in the execution chain. This filter is recommended to be appended as the first client filter using GrpcClientBuilder.initializeHttp(GrpcClientBuilder.HttpInitializer) to account for all work done by other filters. It can be appended at another position, considering the following:

• After a tracing filter or any other filter that populates request context, AsyncContext, MDC, or alters HttpRequestMetaData if that information has to be available for GrpcLifecycleObserver.GrpcExchangeObserver.
• After RetryingHttpRequesterFilter if each retry attempt should be observed as an independent exchange.
• As a connection filter if no user-defined RetryingHttpRequesterFilter is appended manually but the default auto-retries should be observed as an independent exchange.
• As the last connection filter if only network interactions should be observed without accounting for work of any other filters.
• After TimeoutHttpRequesterFilter (or GrpcFilters.newGrpcDeadlineClientFilterFactory()) if the timeout event should be observed as cancellation instead of an error.
• Before any filter that populates response context or alters HttpResponseMetaData if that information has to be available for GrpcLifecycleObserver.GrpcExchangeObserver.
• Before any filter that maps/translates HttpResponseMetaData into an exception or throws an exception during response payload body transformation if that exception has to be observed by GrpcLifecycleObserver.GrpcExchangeObserver.
• Using SingleAddressHttpClientBuilder.appendClientFilter(Predicate, StreamingHttpClientFilterFactory) or SingleAddressHttpClientBuilder.appendConnectionFilter(Predicate, StreamingHttpConnectionFilterFactory) if the observer should be applied conditionally.

Constructor Summary

Constructors

Constructor	Description
GrpcLifecycleObserverRequesterFilter(GrpcLifecycleObserver observer)	Create a new instance.

Method Summary

Modifier and Type	Method	Description
List<? extends GrpcLifecycleObserver>	lifecycleObservers()	Returns the GrpcLifecycleObservers used by this filter.
final HttpExecutionStrategy	requiredOffloads()	Return an ExecutionStrategy that describes the offloads required by the influencer.

Methods inherited from class io.servicetalk.http.netty.HttpLifecycleObserverRequesterFilter

create, create

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.servicetalk.http.api.HttpExecutionStrategyInfluencer

influenceStrategy, requiredOffloads

Constructor Details

GrpcLifecycleObserverRequesterFilter

public GrpcLifecycleObserverRequesterFilter(GrpcLifecycleObserver observer)

Create a new instance.

Parameters:

observer - The observer implementation that consumes gRPC lifecycle events.

Method Details

lifecycleObservers

public List<? extends GrpcLifecycleObserver> lifecycleObservers()

Returns the GrpcLifecycleObservers used by this filter.

Returns:

a List of GrpcLifecycleObservers used by this filter

requiredOffloads

public final HttpExecutionStrategy requiredOffloads()

Description copied from interface: HttpExecutionStrategyInfluencer

Return an ExecutionStrategy that describes the offloads required by the influencer.

The provided default implementation requests offloading of all operations. Implementations that require no offloading should be careful to return HttpExecutionStrategies.offloadNone() rather than HttpExecutionStrategies.offloadNever(). Implementations should avoid returning HttpExecutionStrategies.defaultStrategy(), instead returning the strategy they require or HttpExecutionStrategies.offloadAll() if offloading for all paths is required (safe default).

Specified by:

requiredOffloads in interface ExecutionStrategyInfluencer<HttpExecutionStrategy>

Specified by:

requiredOffloads in interface HttpExecutionStrategyInfluencer

Returns:

the ExecutionStrategy required by the influencer.