org.apache.beam.runners.fnexecution.control

Class FnApiControlClient

java.lang.Object

org.apache.beam.runners.fnexecution.control.FnApiControlClient

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, InstructionRequestHandler

public class FnApiControlClient
extends java.lang.Object
implements java.io.Closeable, InstructionRequestHandler

A client for the control plane of an SDK harness, which can issue requests to it over the Fn API.

This class presents a low-level Java API de-inverting the Fn API's gRPC layer.

The Fn API is inverted so the runner is the server and the SDK harness is the client, for firewalling reasons (the runner may execute in a more privileged environment forbidding outbound connections).

This low-level client is responsible only for correlating requests with responses.

Method Summary

Modifier and Type	Method and Description
io.grpc.stub.StreamObserver<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionResponse>	asResponseObserver()
void	close()
static FnApiControlClient	forRequestObserver(io.grpc.stub.StreamObserver<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionRequest> requestObserver) Returns a FnApiControlClient which will submit its requests to the provided observer.
java.util.concurrent.CompletionStage<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionResponse>	handle(org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionRequest request)

Methods inherited from class java.lang.Object

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

Method Detail

forRequestObserver

public static FnApiControlClient forRequestObserver(io.grpc.stub.StreamObserver<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionRequest> requestObserver)

Returns a FnApiControlClient which will submit its requests to the provided observer.

It is the responsibility of the caller to register this object as an observer of incoming responses (this will generally be done as part of fulfilling the contract of a gRPC service).

handle

public java.util.concurrent.CompletionStage<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionResponse> handle(org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionRequest request)

Specified by:

handle in interface InstructionRequestHandler

asResponseObserver

public io.grpc.stub.StreamObserver<org.apache.beam.model.fnexecution.v1.BeamFnApi.InstructionResponse> asResponseObserver()

close

public void close()

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable