Package org.a2aproject.sdk.server.grpc.quarkus

Class QuarkusGrpcHandler

java.lang.Object

org.a2aproject.sdk.grpc.A2AServiceGrpc.A2AServiceImplBase

org.a2aproject.sdk.transport.grpc.handler.GrpcHandler

org.a2aproject.sdk.server.grpc.quarkus.QuarkusGrpcHandler

All Implemented Interfaces:

io.grpc.BindableService, A2AServiceGrpc.AsyncService

 
public class QuarkusGrpcHandler
extends GrpcHandler

Quarkus gRPC service implementation for the A2A protocol.

This class provides a production-ready gRPC service built on Quarkus gRPC, implementing the A2A protocol with CDI integration, authentication, and interceptor support for metadata extraction.

CDI Integration

This class is a Quarkus gRPC service (@GrpcService) that automatically:

• Injects the public AgentCard (required)
• Injects the extended AgentCard (optional)
• Injects the RequestHandler for protocol operations
• Injects the CallContextFactory for custom context creation (optional)
• Injects the Executor for async operations

Security

The service is protected with @Authenticated annotation, requiring authentication for all gRPC method calls. Configure authentication in application.properties:

 quarkus.security.users.embedded.enabled=true
 quarkus.security.users.embedded.plain-text=true
 quarkus.security.users.embedded.users.alice=password
 

Interceptor Registration

The @RegisterInterceptor annotation automatically registers A2AExtensionsInterceptor to capture A2A protocol headers and metadata before service methods are invoked.

Extension Points

To customize context creation, provide a CDI bean implementing CallContextFactory:

 @ApplicationScoped
 public class CustomCallContextFactory implements CallContextFactory {
     @Override
     public <V> ServerCallContext create(StreamObserver<V> responseObserver) {
         // Custom context creation logic
     }
 }
 

See Also:

• GrpcHandler
• A2AExtensionsInterceptor
• CallContextFactory

Constructor Summary

Constructors

Constructor	Description
QuarkusGrpcHandler(AgentCard agentCard, jakarta.enterprise.inject.Instance<AgentCard> extendedAgentCard, RequestHandler requestHandler, jakarta.enterprise.inject.Instance<CallContextFactory> callContextFactoryInstance, Executor executor)	Constructs a new QuarkusGrpcHandler with CDI-injected dependencies.

Method Summary

Modifier and Type	Method	Description
protected AgentCard	getAgentCard()	Returns the public agent card defining the agent's capabilities and metadata.
protected CallContextFactory	getCallContextFactory()	Returns the custom call context factory, or null to use default context creation.
protected Executor	getExecutor()	Returns the executor for running async operations (streaming subscriptions, etc.).
protected AgentCard	getExtendedAgentCard()	Returns the extended agent card with additional capabilities, or null if not configured.
protected RequestHandler	getRequestHandler()	Returns the request handler instance for processing A2A protocol requests.

Methods inherited from class org.a2aproject.sdk.transport.grpc.handler.GrpcHandler

cancelTask, createTaskPushNotificationConfig, deleteTaskPushNotificationConfig, getCurrentMetadata, getCurrentMethodName, getCurrentPeerInfo, getDeploymentClassLoader, getExtendedAgentCard, getTask, getTaskPushNotificationConfig, listTaskPushNotificationConfigs, listTasks, sendMessage, sendStreamingMessage, setStreamingSubscribedRunnable, subscribeToTask

Methods inherited from class org.a2aproject.sdk.grpc.A2AServiceGrpc.A2AServiceImplBase

bindService

Methods inherited from class java.lang.Object

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

Constructor Details

QuarkusGrpcHandler

@Inject
public QuarkusGrpcHandler(AgentCard agentCard,
 jakarta.enterprise.inject.Instance<AgentCard> extendedAgentCard,
 RequestHandler requestHandler,
 jakarta.enterprise.inject.Instance<CallContextFactory> callContextFactoryInstance,
 Executor executor)

Constructs a new QuarkusGrpcHandler with CDI-injected dependencies.

This constructor is invoked by CDI to create the gRPC service bean, injecting all required and optional dependencies.

Required Dependencies:

• agentCard - Public agent card defining capabilities
• requestHandler - Request handler for protocol operations
• executor - Executor for async operations

Optional Dependencies:

• extendedAgentCard - Extended agent card (can be unresolvable)
• callContextFactoryInstance - Custom context factory (can be unsatisfied)

Parameters:

agentCard - the public agent card (qualified with @PublicAgentCard)

extendedAgentCard - the extended agent card instance (qualified with @ExtendedAgentCard)

requestHandler - the request handler for protocol operations

callContextFactoryInstance - the call context factory instance (optional)

executor - the executor for async operations (qualified with @Internal)

Method Details

getRequestHandler

protected RequestHandler getRequestHandler()

Description copied from class: GrpcHandler

Returns the request handler instance for processing A2A protocol requests.

Specified by:

getRequestHandler in class GrpcHandler

Returns:

the request handler

getAgentCard

protected AgentCard getAgentCard()

Description copied from class: GrpcHandler

Returns the public agent card defining the agent's capabilities and metadata.

Specified by:

getAgentCard in class GrpcHandler

Returns:

the agent card

getExtendedAgentCard

protected AgentCard getExtendedAgentCard()

Description copied from class: GrpcHandler

Returns the extended agent card with additional capabilities, or null if not configured.

Specified by:

getExtendedAgentCard in class GrpcHandler

Returns:

the extended agent card, or null if not available

getCallContextFactory

protected CallContextFactory getCallContextFactory()

Description copied from class: GrpcHandler

Returns the custom call context factory, or null to use default context creation.

Specified by:

getCallContextFactory in class GrpcHandler

Returns:

the call context factory, or null for default behavior

getExecutor

protected Executor getExecutor()

Description copied from class: GrpcHandler

Returns the executor for running async operations (streaming subscriptions, etc.).

Specified by:

getExecutor in class GrpcHandler

Returns:

the executor