valkey-pubsub

Sample code for Jedis pub/sub

Project Description

valkey-pubsub provides a minimal example of how to use the Jedis client to publish and subscribe to messages on a Valkey (Redis) server. The project wraps Jedis with simple interfaces for message publishing and subscribing and exposes a command-line utility built with Picocli.

Features

• Publish messages to a channel using Jedis
• Subscribe to channels and print incoming messages
• CLI options for host, port, SSL, authentication, database, timeouts, and connection pooling
• Structured logging with trace IDs
• Executable fat JAR via Maven Shade plugin

Prerequisites

• Java 21 or later
• Maven 3.8+ (for building)

Build

mvn clean package

This produces target/valkey-pubsub-0.1.0.jar.

Usage

Publish a JSON payload to a channel:

java -jar target/valkey-pubsub-0.1.0.jar publish --host 127.0.0.1 --port 6379 test '{"robotId":"R1"}'

Subscribe to a channel:

java -jar target/valkey-pubsub-0.1.0.jar subscribe --host 127.0.0.1 --port 6379 test

Programmatic Example

The project can also be used directly from application code. The following class keeps a single Jedis pool and exposes a simple publish method:

// MyPublisher.java
import com.example.valkey.core.MessagePublisher;
import com.example.valkey.jedis.*;
import redis.clients.jedis.JedisPool;

public final class MyPublisher implements AutoCloseable {
    private final JedisPool pool;
    private final MessagePublisher publisher;

    public MyPublisher(ValkeyProps props) {
        this.pool = JedisPools.create(props);
        this.publisher = new JedisMessagePublisher(pool);
    }

    public long publish(String channel, String message) {
        return publisher.publish(channel, message);
    }

    @Override
    public void close() {
        pool.close();
    }
}

Call it from other code and handle the runtime exceptions declared by MessagePublisher:

ValkeyProps props = ValkeyProps.defaults();
try (MyPublisher pub = new MyPublisher(props)) {
    pub.publish("test", "{\"robotId\":\"R1\"}");
} catch (ValkeyUnavailableException | PublishException e) {
    // handle connection or publish failures
} catch (NullPointerException e) {
    // handle null channel or message
}

If you want to create a MyPublisher within the constructor and keep the pool alive afterward, use a regular try-catch block to catch the initialization exception as shown below. Avoid using try-with-resources within the constructor, as it closes the MyPublisher (i.e., the pool) when the block ends. This prevents it from persisting if you need it to live longer.

    private final MyPublisher publisher;

    public SomeService(ValkeyProps props) {
        try {
            // Here, generate a MyPublisher that internally holds a Jedis pool.
            this.publisher = new MyPublisher(props);
        } catch (ValkeyUnavailableException e) {
            // If initialization fails, wrap and notify
            throw new IllegalStateException("Failed to initialize publisher", e);
        }
    }

License

This project is licensed under the MIT License. See LICENSE.