S34J Pub Sub

A google pub sub library to be used in Spring

Installation

Installation using gradle

compile 'us.cuatoi.s34j:s34j-pubsub:0.7.3'

Installation using maven

<dependency>
    <groupId>us.cuatoi.s34j</groupId>
    <artifactId>s34j-pubsub</artifactId>
    <version>0.7.3</version>
</dependency>

Quick Start

Provide projectId and base64 credential using properties

s34j.pubsub.project=pubsub-demo
s34j.pubsub.credentialBase64=ew0KICAidHlwZS...

Annotate your application with EnablePubSub annotation

@SpringBootApplication
@EnablePubSub
public class PubSubTestApplication {
    
}

Annotate method with PubSubListener to receive message

public class PubSubTestApplication {
    @PubSubListener
    public void onTestMessage(TestMessage message) { 
        logger.info("onTestMessage message={}", message);
    }
}

Publish a message using PubSub

public class PubSubTestApplication {
    @Autowired
    private PubSub pubSub;
    
    public void sendSomeMessage() { 
        pubSub.publish(new TestMessage());
    }
}

How to obtain credential to use

Copy project from dashboard page

Go to IAM & admin > Service Accounts

Create a new key with json format

Download and format key to base64

Use the key in property file

s34j.pubsub.credentialBase64=ew0KICAidHlwZS...

Advanced use cases

Provide projectId and base64 credential for each topic by specifying topic_name.project and topic_name.credentialBase64. S34J Pub Sub will load and use credential for that topic

sample_topic.project=pubsub-demo
sample_topic.credentialBase64=ew0KICAidHlwZS...

Use addUniqueSuffix to add an unique suffix to subscription name. This is used when you want to broadcast a message to all server.

public class PubSubTestApplication {
    @PubSubListener(addUniqueSuffix = true)
    public void onTestMessage(TestMessage message) { 
    }
}

Use PubSubHandler to quickly send response to a channel

@PubSubHandler(requestTopic = "test_request", responseTopic = "test_response")
public String requestResponseHandled(String message) {
    return "Received " + message + " at " + new Date();
}

PubSubHandler can be used in junction with RequestResponse to quickly route message using Google Pub Sub

@Autowired
private RequestResponse requestResponse;

CompletableFuture<String> response = requestResponse
    .sendRequestForResponse("test_request", "Message: " + new Date(), "test_response", String.class);
response.whenCompleteAsync((s, e) -> {
    logger.info("sendRequestForResponse s={}, ex={}", s, e);
});