Class BlockingOffloadInterceptor

java.lang.Object

org.a2aproject.sdk.server.grpc.quarkus.BlockingOffloadInterceptor

All Implemented Interfaces:

io.grpc.ServerInterceptor

@ApplicationScoped
public class BlockingOffloadInterceptor
extends Object
implements io.grpc.ServerInterceptor

gRPC server interceptor that offloads handler execution from the Vert.x event loop to a worker thread, using a forked gRPC Context.

In Quarkus separate-server mode (quarkus.grpc.server.use-separate-server=true), the @Blocking annotation is ignored and gRPC handlers run on the Vert.x event loop. Synchronous operations like sendMessage() deadlock the event loop. This interceptor wraps the onHalfClose() callback to run the handler on a worker thread instead.

The context is forked (Context.fork()) so that the handler's outbound gRPC calls do not inherit the inbound call's cancellation signal. Without this, Quarkus' ContextStorageOverride propagates the server context through the ManagedExecutor, causing outbound client calls to be cancelled when the inbound caller disconnects.

This applies to both unary and server-streaming methods (which both have a single inbound request). Client-streaming and bidi-streaming methods are excluded.

Constructor Summary

Constructors

Constructor	Description
BlockingOffloadInterceptor(Executor executor)

Method Summary

Modifier and Type	Method	Description
<ReqT,RespT> io.grpc.ServerCall.Listener<ReqT>	interceptCall(io.grpc.ServerCall<ReqT,RespT> call, io.grpc.Metadata headers, io.grpc.ServerCallHandler<ReqT,RespT> next)

Methods inherited from class Object

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

Constructor Details

BlockingOffloadInterceptor

@Inject
public BlockingOffloadInterceptor(Executor executor)

Method Details

interceptCall

public <ReqT,RespT>
io.grpc.ServerCall.Listener<ReqT> interceptCall(io.grpc.ServerCall<ReqT,RespT> call,
 io.grpc.Metadata headers,
 io.grpc.ServerCallHandler<ReqT,RespT> next)

Specified by:

interceptCall in interface io.grpc.ServerInterceptor