Add Support for Redis as a Persistence Database in Flower

[NitinSingh8]

Summary

This pull request introduces support for using Redis as a persistence database in Flower. This enhancement allows users to store and retrieve the state data using Redis, providing a more scalable and distributed solution compared to file-based storage.

Key Changes

• README Update: Added documentation on how to configure Flower to use Redis for persistence, including the necessary command-line arguments.
• Redis Integration: Modified flower/events.py to support Redis as a backend for state persistence.
  • Added new parameters: redis_host, redis_port, redis_db, redis_key, and redis_ssl.
  • Implemented logic to load and save state data to Redis using redis.StrictRedis.
  • Ensured backward compatibility by maintaining support for file-based persistence using shelve.

Usage

To use Redis as a persistence database, run Flower with the following command-line arguments:

bash
celery -A tasks.app flower --broker=amqp://guest:guest@localhost:5672// --redis_host=localhost --redis_port=6379 --redis_db=0 --redis_key=flower --redis_ssl=True

Benefits

• Scalability: Redis provides a scalable solution for state persistence, especially in distributed environments.
• Performance: Redis offers fast read and write operations, improving the performance of state management.
• Flexibility: Users can choose between Redis and file-based storage based on their requirements.

Testing

• Verified that state data is correctly saved and loaded from Redis.
• Ensured that existing functionality with file-based storage remains unaffected.

Notes

• Ensure that the Redis server is properly configured and accessible from the Flower instance.
• The default Redis key is set to flower, but it can be customized as needed.