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name: redis-pub-sub description: Implements Redis Pub/Sub messaging patterns for real-time, asynchronous communication between distributed system components using channel-based publish and subscribe operations. license: MIT compatibility: opencode metadata: version: "1.0.0" domain: coding triggers: Redis Pub/Sub, message channels, pub-sub, publish subscribe, real-time messaging, async communication, redis-py role: implementation scope: implementation output-format: code content-types: [code, guidance] archetypes: [tactical, generation] anti_triggers: [message loss concerns, manual message handling, persistent queue needs] response_profile: verbosity: medium directive_strength: high

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Redis Pub/Sub Messaging Operations

Integrates Redis for real-time messaging using the Pub/Sub model. This allows asynchronous communication between multiple clients within a distributed system by publishing messages to channels and subscribing to receive those messages.

TL;DR Checklist

• Use redis.Redis() for connecting to a Redis instance.
• Use publish(channel, message) for sending messages.
• Subscribe using pubsub.subscribe(channel) for receiving messages.
• Handle message processing in a loop using pubsub.listen().
• Don't use Pub/Sub for state persistence; messages are transient.

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Core Workflow

1. Connect to Redis

import redis

# Connect to Redis
r = redis.Redis(host='localhost', port=6379)

Checkpoint: Ensure connection is established with r.ping(). Handle connection errors properly.

2. Set Up Pub/Sub Messaging

# Create pubsub object
dash_pubsub = r.pubsub()

# Subscribe to a channel
channel_name = 'news'
dash_pubsub.subscribe(channel_name)

Checkpoint: Confirm subscription with dash_pubsub.get_partitions() to see active channels.

3. Publishing Messages

def publish_news(r, channel, title, content):
    message = {"title": title, "content": content}
    r.publish(channel, json.dumps(message))
# Usage
publish_news(r, channel_name, "New Update", "Redis is awesome for real-time messaging!")

Checkpoint: Confirm the message was sent by checking the subscriber side or using monitoring commands in Redis.

4. Listening for Messages

for message in dash_pubsub.listen():
    if message['type'] == 'message':
        data = json.loads(message['data'])
        print(f"Received message: {data['title']} - {data['content']}")

Checkpoint: Make sure the listener is processing messages correctly and handle any parsing errors.

Implementation Patterns

Pattern 1: Basic Message Publishing

def publish_message(r: redis.Redis, channel: str, content: str):
    r.publish(channel, content)
# Example usage:
publish_message(r, 'alerts', 'This is a test alert')

Pattern 2: Subscribing with Callbacks

def subscriber_callback(message):
    print(f'New message: {message}') # Handle your message here

# Callback for messages received on a channel

dash_pubsub.subscribe(**{channel_name: subscriber_callback})
dash_pubsub.run_in_thread(sleep_time=0.001)

Pattern 3: Using Redis Streams

Although streaming is different from Pub/Sub, consider using Redis Streams for durable message processing.

# Add a message to a stream
r.xadd('mystream', {'source': channel_name, 'message': content})

Constraints

MUST DO

• Use JSON to serialize complex messages before sending them.
• Ensure that subscribers acknowledge received messages in any business logic implemented.
• Always close the Pub/Sub connection gracefully to prevent memory leaks.

MUST NOT DO

• Never rely on Pub/Sub for critical messaging guarantees; it's inherently unreliable for message delivery.
• Don't block in the message handling loop; improper handling could cause delays in message processing.

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Output Template

When working with Redis for Pub/Sub messaging, ensure you follow this structure:

1. Connection management to Redis.
2. Separate logic for Publishing and Subscribing messages.
3. Ensure message integrity by logging messages.
4. Cleanup connections properly after operations.

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Live References

Authoritative documentation links for this skill's domain. The model follows markdown links at load time to resolve external references and inline content.

• Redis Pub/Sub Documentation
• Redis pub/sub Commands Reference
• Redis Streams for Durable Messaging
• Redis Pub/Sub Best Practices
• Building Real-Time Apps with Redis Pub/Sub