Redis Operations

Instructions

Operate Redis instances in Docker environments for caching and message brokering.

Caching strategies:

• Set TTL on all cache keys — no unbounded keys: SET key value EX 3600
• Use LRU eviction policy (maxmemory-policy allkeys-lru) to prevent OOM
• Cache invalidation: delete on write, or use short TTLs for eventually-consistent data
• Hash types for structured objects: HSET user:123 name "Alice" email "alice@example.com"

Celery broker configuration:

• Broker URL: redis://redis:6379/1 — use DB 1 to separate from cache on DB 0
• Result backend: redis://redis:6379/2 for task results (separate DB again)
• Set broker_transport_options with visibility_timeout matching your longest task duration
• Monitor queues: redis-cli -n 1 LLEN celery to check queue depth

Pub/sub for real-time events:

• Publish: PUBLISH channel:notifications '{"event": "update", "id": 123}'
• Subscribe in application code; do not use redis-cli SUBSCRIBE in production
• Pub/sub messages are fire-and-forget — use Redis Streams for durable messaging

Key naming conventions:

• Pattern: namespace:entity:id — e.g., dify:session:abc123, iti:cache:user:456
• Use colons as separators for visual grouping in redis-cli KEYS output
• Prefix all keys with application namespace to prevent collisions in shared instances

Health checks:

• Docker healthcheck: redis-cli ping — expects PONG response
• Compose config: healthcheck: test: ["CMD", "redis-cli", "ping"] interval: 10s timeout: 5s retries: 3

Monitoring:

• redis-cli INFO — memory usage, connected clients, keyspace stats
• redis-cli INFO memory — check used_memory_human and maxmemory
• redis-cli MONITOR — real-time command stream (development only; significant performance impact)
• redis-cli DBSIZE — total key count per database
• Alert on memory usage >80% of maxmemory

ITI reference pattern:

• Image: redis:7-alpine for minimal footprint
• Shared instance serving Dify cache (DB 0) and Celery broker (DB 1)
• Persist with AOF (appendonly yes) for durability; RDB snapshots as supplementary backup
• Resource allocation: 512 MB maxmemory sufficient for typical ITI workloads