Add gRPC support

grpc/pom.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.wildfly.extras.a2a</groupId>
+        <artifactId>a2a-java-sdk-server-jakarta-parent</artifactId>
+        <version>0.2.6.Beta1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>a2a-java-sdk-server-jakarta-grpc</artifactId>
+    <packaging>jar</packaging>
+
+    <name>WildFly Extras - Java A2A SDK for Jakarta gRPC</name>
+    <description>Java SDK for the Agent2Agent Protocol (A2A) - SDK - Jakarta - gRPC integration</description>
+
+    <dependencies>
+        <!-- A2A spec-grpc dependency -->
+        <dependency>
+            <groupId>io.github.a2asdk</groupId>
+            <artifactId>a2a-java-sdk-transport-grpc</artifactId>
+            <version>${version.sdk}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- Jakarta APIs needed for CDI and annotation support -->
+        <dependency>
+            <groupId>jakarta.annotation</groupId>
+            <artifactId>jakarta.annotation-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>jakarta.enterprise</groupId>
+            <artifactId>jakarta.enterprise.cdi-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>jakarta.inject</groupId>
+            <artifactId>jakarta.inject-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- A2A server common for @PublicAgentCard and RequestHandler -->
+        <dependency>
+            <groupId>io.github.a2asdk</groupId>
+            <artifactId>a2a-java-sdk-server-common</artifactId>
+            <version>${version.sdk}</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+</project>

grpc/src/main/java/org/wildfly/extras/a2a/server/apps/grpc/GrpcBeanInitializer.java

@@ -0,0 +1,55 @@
+package org.wildfly.extras.a2a.server.apps.grpc;
+
+import jakarta.annotation.PreDestroy;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.context.Initialized;
+import jakarta.enterprise.event.Observes;
+import jakarta.enterprise.inject.Instance;
+import jakarta.inject.Inject;
+
+import io.a2a.server.PublicAgentCard;
+import io.a2a.server.requesthandlers.RequestHandler;
+import io.a2a.spec.AgentCard;
+import io.a2a.transport.grpc.handler.CallContextFactory;
+
+/**
+ * Bean initializer that observes application startup events.
+ *
+ * Since CDI is not available on gRPC threads, we capture the CDI beans
+ * during application startup and store them statically for use by
+ * the WildFly gRPC subsystem.
+ */
+@ApplicationScoped
+public class GrpcBeanInitializer {
+
+    @Inject
+    @PublicAgentCard
+    AgentCard agentCard;
+
+    @Inject
+    RequestHandler requestHandler;
+
+    @Inject
+    Instance<CallContextFactory> callContextFactory;
+
+    /**
+     * Observes the application startup event to eagerly initialize the gRPC cache.
+     */
+    public void onStartup(@Observes @Initialized(ApplicationScoped.class) Object init) {
+        System.out.println("*** GrpcBeanInitializer.onStartup() called - ApplicationScoped initialized ***");
+        try {
+            // Cache CDI beans for gRPC threads to use since CDI is not available on those threads
+            CallContextFactory ccf = callContextFactory.isUnsatisfied() ? null : callContextFactory.get();
+            WildFlyGrpcHandler.setStaticBeans(agentCard, requestHandler, ccf);
+            System.out.println("*** GrpcBeanInitializer successfully cached beans: agentCard=" + agentCard + ", requestHandler=" + requestHandler + ", callContextFactory=" + ccf + " ***");
+        } catch (Exception e) {
+            System.err.println("*** GrpcBeanInitializer.onStartup() failed: " + e.getMessage());
+            e.printStackTrace();
+        }
+    }
+
+    @PreDestroy
+    public void cleanup() {
+        WildFlyGrpcHandler.setStaticBeans(null, null, null);
+    }
+}

grpc/src/main/java/org/wildfly/extras/a2a/server/apps/grpc/WildFlyGrpcHandler.java

@@ -0,0 +1,58 @@
+package org.wildfly.extras.a2a.server.apps.grpc;
+
+import io.a2a.server.requesthandlers.RequestHandler;
+import io.a2a.spec.AgentCard;
+import io.a2a.transport.grpc.handler.CallContextFactory;
+import io.a2a.transport.grpc.handler.GrpcHandler;
+
+/**
+ * WildFly gRPC Handler that uses static cache for CDI beans.
+ *
+ * The WildFly gRPC subsystem instantiates this class directly using
+ * reflection and the default constructor, bypassing CDI completely.
+ *
+ * Since CDI is not available on gRPC threads, we use static cache
+ * populated during application startup when CDI is available.
+ */
+public class WildFlyGrpcHandler extends GrpcHandler {
+
+    // Static cache populated during application startup by GrpcBeanInitializer
+    private static volatile AgentCard staticAgentCard;
+    private static volatile RequestHandler staticRequestHandler;
+    private static volatile CallContextFactory staticCallContextFactory;
+
+    public WildFlyGrpcHandler() {
+        // Default constructor - the only one used by WildFly gRPC subsystem
+    }
+
+    /**
+     * Called by GrpcBeanInitializer during CDI initialization to cache beans
+     * for use by gRPC threads where CDI is not available.
+     */
+    static void setStaticBeans(AgentCard agentCard, RequestHandler requestHandler, CallContextFactory callContextFactory) {
+        staticAgentCard = agentCard;
+        staticRequestHandler = requestHandler;
+        staticCallContextFactory = callContextFactory;
+    }
+
+    @Override
+    protected RequestHandler getRequestHandler() {
+        if (staticRequestHandler == null) {
+            throw new RuntimeException("RequestHandler not available. ApplicationStartup may not have run yet.");
+        }
+        return staticRequestHandler;
+    }
+
+    @Override
+    protected AgentCard getAgentCard() {
+        if (staticAgentCard == null) {
+            throw new RuntimeException("AgentCard not available. ApplicationStartup may not have run yet.");
+        }
+        return staticAgentCard;
+    }
+
+    @Override
+    protected CallContextFactory getCallContextFactory() {
+        return staticCallContextFactory; // Can be null if not configured
+    }
+}

grpc/src/main/resources/META-INF/beans.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="https://jakarta.ee/xml/ns/jakartaee"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/beans_4_0.xsd"
+       bean-discovery-mode="annotated">
+</beans>

impl/pom.xml

@@ -20,7 +20,7 @@
     <dependencies>
         <dependency>
             <groupId>io.github.a2asdk</groupId>
-            <artifactId>a2a-java-sdk-server-common</artifactId>
+            <artifactId>a2a-java-sdk-transport-jsonrpc</artifactId>
             <exclusions>
                 <exclusion>
                     <groupId>jakarta.enterprise</groupId>

impl/src/main/java/org/wildfly/extras/a2a/server/apps/jakarta/A2AServerResource.java

@@ -29,7 +29,6 @@
 import io.a2a.server.ServerCallContext;
 import io.a2a.server.auth.UnauthenticatedUser;
 import io.a2a.server.auth.User;
-import io.a2a.server.requesthandlers.JSONRPCHandler;
 import io.a2a.server.util.async.Internal;
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.CancelTaskRequest;
@@ -56,11 +55,12 @@
 import io.a2a.spec.StreamingJSONRPCRequest;
 import io.a2a.spec.TaskResubscriptionRequest;
 import io.a2a.spec.UnsupportedOperationError;
+import io.a2a.transport.jsonrpc.handler.JSONRPCHandler;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 @Path("/")
-public class A2AServerResource {
+    public class A2AServerResource {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(A2AServerResource.class);
 

pom.xml

@@ -45,9 +45,11 @@
     <properties>
         <jboss.home>${project.build.directory}${file.separator}wildfly</jboss.home>
         <version.wildfly>36.0.1.Final</version.wildfly>
-        <version.sdk>${project.version}</version.sdk>
+        <version.sdk>0.3.0.Beta1-SNAPSHOT</version.sdk>
         <!-- This needs to be same version as used by the sdk -->
         <version.mutiny-zero>1.1.1</version.mutiny-zero>
+        <!-- gRPC version matching the a2a-java-sdk -->
+        <version.grpc>1.73.0</version.grpc>
 
         <version.jboss-commons-logging>1.0.0.Final</version.jboss-commons-logging>
         <version.hamcrest>2.2</version.hamcrest>
@@ -58,6 +60,7 @@
         <version.org.jboss.arquillian.jakarta>10.0.0.Final</version.org.jboss.arquillian.jakarta>
         <version.shrinkwrap.resolvers>3.3.4</version.shrinkwrap.resolvers>
         <version.rest-assured>5.5.5</version.rest-assured>
+        <version.wildfly.grpc>0.1.12.Final</version.wildfly.grpc>
 
         <jboss.home>${project.build.directory}${file.separator}wildfly</jboss.home>
         <arquillian.java.vm.args></arquillian.java.vm.args>
@@ -117,6 +120,21 @@
                 <artifactId>a2a-java-sdk-spec</artifactId>
                 <version>${version.sdk}</version>
             </dependency>
+            <dependency>
+                <groupId>io.github.a2asdk</groupId>
+                <artifactId>a2a-java-sdk-spec-grpc</artifactId>
+                <version>${version.sdk}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.a2asdk</groupId>
+                <artifactId>a2a-java-sdk-transport-grpc</artifactId>
+                <version>${version.sdk}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.github.a2asdk</groupId>
+                <artifactId>a2a-java-sdk-transport-jsonrpc</artifactId>
+                <version>${version.sdk}</version>
+            </dependency>
             <dependency>
                 <groupId>io.github.a2asdk</groupId>
                 <artifactId>a2a-tck-server</artifactId>
@@ -162,6 +180,37 @@
                 <version>${version.hamcrest}</version>
                 <scope>test</scope>
             </dependency>
+            <!-- gRPC dependencies -->
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-protobuf</artifactId>
+                <version>${version.grpc}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-stub</artifactId>
+                <version>${version.grpc}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-netty</artifactId>
+                <version>${version.grpc}</version>
+            </dependency>
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-netty-shaded</artifactId>
+                <version>${version.grpc}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.google.protobuf</groupId>
+                <artifactId>protobuf-java</artifactId>
+                <version>4.31.1</version>
+            </dependency>
+            <dependency>
+                <groupId>com.google.guava</groupId>
+                <artifactId>failureaccess</artifactId>
+                <version>1.0.2</version>
+            </dependency>
         </dependencies>
     </dependencyManagement>
     <build>
@@ -249,9 +298,11 @@
         </pluginManagement>
     </build>
     <modules>
+        <module>grpc</module>
         <module>impl</module>
         <module>tck</module>
         <module>tests</module>
+        <module>tests-grpc</module>
     </modules>
     <profiles>
         <profile>