Redis Configuration

Connection Setup

ioredis client with connection pooling:

import { Redis } from 'ioredis'

const redis = new Redis({
  host: process.env.REDIS_HOST || 'localhost',
  port: parseInt(process.env.REDIS_PORT || '6379'),
  password: process.env.REDIS_PASSWORD,
  db: parseInt(process.env.REDIS_DB || '0'),
  maxRetriesPerRequest: 3,
  retryStrategy: (times) => {
    const delay = Math.min(times * 50, 2000)
    return delay
  },
  lazyConnect: true,
})

redis.on('error', (err) => {
  console.error('Redis connection error:', err)
})

redis.on('connect', () => {
  console.log('Redis connected')
})

export default redis

Serverless Considerations

Redis in serverless environments (Vercel, Lambda):

Use Redis connection pooling (ioredis handles this)
Consider Upstash Redis (serverless-optimized)
Set lazyConnect: true to avoid connection on module load
Handle cold starts gracefully (fallback to database)
Monitor connection count to avoid exhaustion

Upstash example:

import { Redis } from '@upstash/redis'

const redis = new Redis({
  url: process.env.UPSTASH_REDIS_REST_URL,
  token: process.env.UPSTASH_REDIS_REST_TOKEN,
})

Upstash uses HTTP REST API, avoiding connection pooling issues in serverless.

Cache Implementation Checklist

When implementing caching:

Setup:

Redis client configured with connection pooling
Error handling for Redis connection failures
Fallback to database when Redis unavailable
Environment variables for Redis configuration

Cache Keys:

Consistent key naming convention (entity:identifier)
Hash complex query parameters for deterministic keys
Namespace keys by entity type
Document key patterns

Caching Logic:

Cache-aside pattern (read from cache, fallback to DB)
Serialize/deserialize with JSON.parse/stringify
Handle null/undefined results appropriately
Log cache hits/misses for monitoring

Invalidation:

Invalidate on create/update/delete mutations
Handle cascading invalidation for related entities
Consider bulk invalidation for list queries
Test invalidation across all mutation paths

TTL Configuration:

Define TTL for each data type
Shorter TTL for frequently changing data
Longer TTL for static/rarely changing data
Document TTL choices and rationale

Monitoring:

Track cache hit rate
Monitor cache memory usage
Log invalidation events
Alert on Redis connection failures

2.5 KiB Raw Blame History

Redis Configuration

Connection Setup

Serverless Considerations

Cache Implementation Checklist

2.5 KiB

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