Implement Redis-backed Sync Comment System

[SB2318]

Summary

Implement a Redis-backed synchronization layer for the comment system to enable real-time updates, improve scalability, and reduce database load. This issue also includes setting up and configuring Redis for the backend application.

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Problem Statement

The current comment system relies solely on database operations, which can lead to:

• Higher database load during active discussions.
• Delayed comment synchronization across multiple users.
• Limited scalability for real-time features.
• No centralized event mechanism for comment updates.

A Redis-based synchronization layer will provide fast pub/sub messaging and caching capabilities, allowing comments to stay synchronized across all connected clients.

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Scope

1. Redis Setup

• Configure Redis for local development.
• Add environment variables for Redis connection.
• Create a reusable Redis client.
• Handle automatic reconnection and graceful shutdown.
• Add health checks for Redis connectivity.

2. Comment Synchronization

• Publish comment events to Redis.
• Subscribe to comment events from all backend instances.
• Synchronize:
  • New comments
  • Comment edits
  • Comment deletion
  • Comment reactions (if supported)
• Prevent duplicate event processing.

3. API Integration

• Integrate Redis events into existing comment APIs.
• Ensure database remains the source of truth.
• Broadcast updates after successful database transactions.

4. Real-Time Updates

• Notify connected clients whenever comments change.
• Ensure updates work correctly across multiple backend instances.
• Support horizontal scaling.

5. Error Handling

• Gracefully fall back to database operations if Redis becomes unavailable.
• Log Redis connection failures.
• Retry failed Redis connections.
• Ensure comment creation still succeeds without Redis.

6. Configuration

Add environment variables such as:

REDIS_HOST=
REDIS_PORT=
REDIS_PASSWORD=
REDIS_URL=

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Technical Tasks

• Install Redis client library.
• Create Redis configuration module.
• Implement Redis connection manager.
• Add Redis health check.
• Implement Pub/Sub channels for comments.
• Publish comment events after successful mutations.
• Subscribe to comment events.
• Broadcast updates to connected clients.
• Handle reconnection logic.
• Add logging for Redis operations.
• Update environment documentation.
• Add Docker Compose support (if applicable).

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Acceptance Criteria

• Redis is successfully configured.
• Backend connects to Redis automatically.
• Comment events are synchronized across backend instances.
• Clients receive real-time updates.
• Database remains the single source of truth.
• Redis failures do not prevent comment creation.
• Proper logging and error handling are implemented.
• Documentation includes Redis setup instructions.

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Benefits

• Faster comment synchronization
• Reduced database load
• Improved scalability
• Real-time collaboration
• Ready for horizontal scaling
• Better user experience

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Labels

• enhancement
• backend
• redis
• comments
• realtime
• infrastructure
• good first issue (optional)

[github-actions]

Thank you for creating this issue! We'll look into it as soon as possible. Your contributions are highly appreciated! 😊

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[github-actions]

This issue has been triaged as a backend task (level:advanced).

Expected Effect & Scope: The issue is valid and in scope, proposing a significant backend enhancement involving new infrastructure (Redis) for real-time comment synchronization. This constitutes an architecture change and a large feature, warranting maintainer escalation.

This requires backend investigation and has been routed to @SB2318 for review and prioritization.