Skip to content

apcu-setup.md

Latest commit

 

History

History
51 lines (39 loc) · 1.91 KB

apcu-setup.md

File metadata and controls

51 lines (39 loc) · 1.91 KB
Raw

APCu Cache Setup

Overview

APCu (APC User Cache) provides shared-memory caching for PHP. The application uses it as the backend of Symfony's app cache.

Configuration Files

1. Docker PHP Configuration

  • File: docker/php/apcu.ini
  • Purpose: PHP extension configuration for APCu
  • Key Settings:
    • apc.shm_size=32M - Memory allocation for development
    • apc.enable_cli=1 - Enable APCu in CLI for Symfony console commands
    • apc.ttl=0 - No automatic expiration
    • apc.user_entries_hint=4096 - Expected number of cache entries

2. Symfony Cache Configuration

  • File: config/packages/cache.yaml
  • Purpose: binds the framework app cache to cache.adapter.apcu with a stable prefix_seed. Services receive it via $cacheItemPool: '@cache.app' (see config/services.yaml).

Production Considerations

Memory Allocation

  • Development: 32MB (sufficient for testing)
  • Production: Recommend 128MB-512MB based on usage patterns
  • Monitoring: Use apcu_cache_info() to monitor usage and hit rates

Cache Invalidation

  • Deployment: APCu cache persists across requests but not deployments
  • Manual: php bin/console cache:pool:clear cache.app
  • Automatic: Configure TTLs per cache item where volatility demands it

Fallback Strategy

  • Graceful Degradation: Symfony falls back cleanly when APCu is unavailable (e.g. CLI without apc.enable_cli)

Monitoring and Debugging

  • Symfony Profiler: shows cache operations in the web profiler
  • CLI: php bin/console cache:pool:list lists configured pools
  • Statistics: apcu_cache_info() for hits/misses/memory usage

Security Considerations

  • Namespace: keys are namespaced via prefix_seed: timetracker
  • No Persistence: APCu data does not survive server restarts
  • Sensitive Data: avoid caching passwords or raw authentication tokens; use short TTLs for anything auth-adjacent