I can't send message using google pubsub emulator in spring boot

Question

I'm trying to send push message using the emulator of pubsub, I'm using spring boot too, this is my configuration:

Dependency:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-gcp-starter-pubsub</artifactId>
</dependency>

My bean:

@Configuration
@AutoConfigureBefore(value= GcpPubSubAutoConfiguration.class)
@EnableConfigurationProperties(value= GcpPubSubProperties.class)
public class EmulatorPubSubConfiguration {
    @Value("${spring.gcp.pubsub.projectid}")
    private String projectId;

    @Value("${spring.gcp.pubsub.subscriptorid}")
    private String subscriptorId;

    @Value("${spring.gcp.pubsub.topicid}")
    private String topicId;

    @Bean
    public Publisher pubsubEmulator() throws IOException {
        String hostport = System.getenv("PUBSUB_EMULATOR_HOST");
        ManagedChannel channel = ManagedChannelBuilder.forTarget(hostport).usePlaintext().build();
        try {
            TransportChannelProvider channelProvider =
                    FixedTransportChannelProvider.create(GrpcTransportChannel.create(channel));
            CredentialsProvider credentialsProvider = NoCredentialsProvider.create();

            // Set the channel and credentials provider when creating a `TopicAdminClient`.
            // Similarly for SubscriptionAdminClient
            TopicAdminClient topicClient =
                    TopicAdminClient.create(
                            TopicAdminSettings.newBuilder()
                                    .setTransportChannelProvider(channelProvider)
                                    .setCredentialsProvider(credentialsProvider)
                                    .build());

            ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
            // Set the channel and credentials provider when creating a `Publisher`.
            // Similarly for Subscriber
            return Publisher.newBuilder(topicName)
                    .setChannelProvider(channelProvider)
                    .setCredentialsProvider(credentialsProvider)
                    .build();
        } finally {
            channel.shutdown();
        }
    }
}

Of course, I have set PUBSUB_EMULATOR_HOST system variable to localhost:8085, where is the emulator running

I created a rest controller for testing:

• for send push message

@Autowired
private Publisher pubsubPublisher;

@PostMapping("/send1")
    public String publishMessage(@RequestParam("message") String message) throws InterruptedException, IOException {
        Publisher pubsubPublisher = this.getPublisher();
        ByteString data = ByteString.copyFromUtf8(message);
        PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();
        ApiFuture<String> future =  pubsubPublisher.publish(pubsubMessage);
        //pubsubPublisher.publishAllOutstanding();
        try {
        // Add an asynchronous callback to handle success / failure
        ApiFutures.addCallback(future,
                new ApiFutureCallback<String>() {
                    @Override
                    public void onFailure(Throwable throwable) {
                        if (throwable instanceof ApiException) {
                            ApiException apiException = ((ApiException) throwable);
                            // details on the API exception
                            System.out.println(apiException.getStatusCode().getCode());
                            System.out.println(apiException.isRetryable());
                        }
                        System.out.println("Error publishing message : " + message);
                        System.out.println("Error publishing error : " + throwable.getMessage());
                        System.out.println("Error publishing cause : " + throwable.getCause());
                    }

                    @Override
                    public void onSuccess(String messageId) {
                        // Once published, returns server-assigned message ids (unique within the topic)
                        System.out.println(messageId);
                    }
                },
                MoreExecutors.directExecutor());
        }
        finally {
            if (pubsubPublisher != null) {
                // When finished with the publisher, shutdown to free up resources.
                pubsubPublisher.shutdown();
                pubsubPublisher.awaitTermination(1, TimeUnit.MINUTES);
            }
        }
    return "ok";

• for get message:

@PostMapping("/pushtest")
    public String pushTest(@RequestBody CloudPubSubPushMessage request) {
        System.out.println( "------> message received: " + decode(request.getMessage().getData()) );
        return request.toString();
    }

I have created my topic and subscription in the emulator, I followed this tutorial:

https://cloud.google.com/pubsub/docs/emulator

I'm set the endpoint "pushtest" for get push message in the emulator, with this command:

python subscriber.py PUBSUB_PROJECT_ID create-push TOPIC_ID SUBSCRIPTION_ID PUSH_ENDPOINT

But when I run the test, doesn't reach "/pushtest" endpoint and I'm getting this error:

Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@265d5d05 [Not completed, task = java.util.concurrent.Executors$RunnableAdapter@a8c8be3 [Wrapped task = com.google.common.util.concurrent.TrustedListenableFutureTask@1a53c57c [status=PENDING, info=[task=[running=[NOT STARTED YET], com.google.api.gax.rpc.AttemptCallable@3866e1d0]]]]] rejected from java.util.concurrent.ScheduledThreadPoolExecutor@3f34809a [Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 1]

for assurance that the emulator is running ok, I'm run the test in python with the following command:

python publisher.py PUBSUB_PROJECT_ID publish TOPIC_ID

And I'm getting messages correctly in "pushtest" endpoint.

I don't know why sorry for my hazing.

Thanks for your help.

Answer 1

I found the problem.

Only comment this line in the bean

channel.shutdown();

HAHA very simple.