How to Use Your A2A Server Agent in a Distributed or Cloud Native Environment

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Deployment completed successfully!
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To verify the deployment, run:
  ./verify.sh

To access the agent (via NodePort):
  curl http://localhost:8080/.well-known/agent-card.json

To run the test client (demonstrating load balancing):
  cd ../server
  mvn test-compile exec:java -Dexec.classpathScope=test \
    -Dexec.mainClass="io.a2a.examples.cloud.A2ACloudExampleClient" \
    -Dagent.url="http://localhost:8080"

$ cd ../server
$ mvn test-compile exec:java -Dexec.classpathScope=test \
    -Dexec.mainClass="io.a2a.examples.cloud.A2ACloudExampleClient" \
    -Dagent.url="http://localhost:8080"

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A2A Cloud Deployment Example Client
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Agent URL: http://localhost:8080
Process messages: 8
Message interval: 1500ms

Fetching agent card...
✓ Agent: Cloud Deployment Demo Agent
✓ Description: Demonstrates A2A multi-pod deployment with Kafka event replication, PostgreSQL persistence, and round-robin load balancing across Kubernetes pods

Client task ID: cloud-test-1761754920509

Creating streaming client for subscription...
Creating non-streaming client for sending messages...
✓ Clients created

Step 1: Sending 'start' to create task...
✓ Task created: 2b525ae8-0b2a-43c9-b2fa-007a8b618240
  State: SUBMITTED

Step 2: Subscribing to task for streaming updates...
✓ Subscribed to task updates

Step 3: Sending 8 'process' messages (interval: 1500ms)...
--------------------------------------------
  Artifact #1: Processed by a2a-agent-cb7fd769-5wr8g
    → Pod: a2a-agent-cb7fd769-5wr8g (Total unique pods: 1)
  Artifact #2: Processed by a2a-agent-cb7fd769-5wr8g
    → Pod: a2a-agent-cb7fd769-5wr8g (Total unique pods: 1)
✓ Process message 1 sent
✓ Process message 2 sent
  Artifact #3: Processed by a2a-agent-cb7fd769-x9tdm
    → Pod: a2a-agent-cb7fd769-x9tdm (Total unique pods: 2)
...
✓ Process message 8 sent
  Artifact #13: Processed by a2a-agent-cb7fd769-5wr8g
    → Pod: a2a-agent-cb7fd769-5wr8g (Total unique pods: 2)

Waiting for process artifacts to arrive...

Step 4: Sending 'complete' to finalize task...
  Artifact #14: Completed by a2a-agent-cb7fd769-5wr8g
    → Pod: a2a-agent-cb7fd769-5wr8g (Total unique pods: 2)
ℹ Subscription stream closed (expected after task completion)
✓ Complete message sent, task state: WORKING

Waiting for task to complete...
⚠ Timeout waiting for task completion

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Test Results
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Total artifacts received: 14
Unique pods observed: 2
Pod names and counts: {a2a-agent-cb7fd769-x9tdm=3, a2a-agent-cb7fd769-5wr8g=11}

✓ TEST PASSED - Successfully demonstrated multi-pod processing!
  Messages were handled by 2 different pods.
  This proves that:
    - Load balancing is working (round-robin across pods)
    - Event replication is working (subscriber sees events from all pods)
    - Database persistence is working (task state shared across pods)

@ApplicationScoped
public class CloudAgentCardProducer {

    @ConfigProperty(name = "agent.url", defaultValue = "http://localhost:8080") (1)
    String agentUrl;

    @Produces
    @PublicAgentCard
    public AgentCard agentCard() {
        return new AgentCard.Builder()
                .name("Cloud Deployment Demo Agent")
                .description("Demonstrates A2A multi-pod deployment with Kafka event replication, " +
                        "PostgreSQL persistence, and round-robin load balancing across Kubernetes pods")
                .url(agentUrl) (1)
                .version("1.0.0")
                .capabilities(new AgentCapabilities.Builder()
                        .streaming(true) (2)
                        .pushNotifications(false)
                        .stateTransitionHistory(false)
                        .build())
                .defaultInputModes(Collections.singletonList("text"))
                .defaultOutputModes(Collections.singletonList("text"))
                .skills(Collections.singletonList(
                        new AgentSkill.Builder()
                                .id("multi_pod_demo")
                                .name("Multi-Pod Replication Demo")
                                .description("Demonstrates cross-pod event replication. " + (3)
                                        "Send 'start' to initialize, 'process' to add artifacts, " +
                                        "'complete' to finalize. Each artifact shows which pod processed it.")
                                .tags(List.of("demo", "cloud", "kubernetes", "replication"))
                                .examples(List.of(
                                        "start",
                                        "process",
                                        "complete"
                                ))
                                .build()
                ))
                .protocolVersion("0.3.0")
                .build();
    }
}

@ApplicationScoped
public class CloudAgentExecutorProducer {
   @Produces
    public AgentExecutor agentExecutor() {
        return new CloudAgentExecutor();
    }

    private static class CloudAgentExecutor implements AgentExecutor {

        @Override
        public void execute(RequestContext context, EventQueue eventQueue) throws JSONRPCError {
            TaskUpdater updater = new TaskUpdater(context, eventQueue); (1)

            try {
                // Extract user message and normalize
                String messageText = extractTextFromMessage(context.getMessage()).trim().toLowerCase();
                // Get pod name from environment (set by Kubernetes Downward API)
                String podName = System.getenv("POD_NAME"); (2)

                // Handle message based on command
                if (context.getTask() == null) { (3)
                    // Initial message - create task in SUBMITTED → WORKING state
                    // This will have the `start` command
                    updater.submit();
                    updater.startWork();
                    String artifactText = "Started by " + podName;
                    List<Part<?>> parts = List.of(new TextPart(artifactText, null));
                    updater.addArtifact(parts);
                } else if ("complete".equals(messageText)) { (5)
                    // Completion trigger - add final artifact and complete
                    String artifactText = "Completed by " + podName;
                    List<Part<?>> parts = List.of(new TextPart(artifactText, null));
                    updater.addArtifact(parts);
                    updater.complete();
                } else { (4)
                    // Subsequent messages - add artifacts (fire-and-forget, stays in WORKING)
                    // This is for the `process` commands
                    String artifactText = "Processed by " + podName;
                    List<Part<?>> parts = List.of(new TextPart(artifactText, null));
                    updater.addArtifact(parts);
                    // No state change - task remains in WORKING
                    LOGGER.info("Artifact added on pod: {}", podName);
                }

            } catch (JSONRPCError e) {
                LOGGER.error("JSONRPC error processing task", e);
                throw e;
            } catch (Exception e) {
                LOGGER.error("Error processing task", e);
                throw new InternalError("Processing failed: " + e.getMessage());
            }
        }
}