symfony-cache · diff
git:20260917.3d83f4c to git:20261005.96060cb
19 added, 13 removed. Audit A to A.
---
name: symfony-cache
description: Implement caching with the Symfony Cache component; configure pools, use tags for invalidation, prevent stampede
capabilities: [read, search, edit, shell]
tags: [architecture, cache, performance]
# projected by `bun run build` — do not edit by hand
allowed-tools:
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- Write
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---
-
# Symfony Cache (Symfony)
## Use when
- - Implementing asynchronous workflows with Messenger/Scheduler/Cache.
- - Stabilizing retries and failure transports.
+ - Caching expensive reads: repository results, computed values, third-party responses.
+ - Choosing or configuring a pool and its adapter (filesystem, Redis, APCu, chained).
+ - Invalidating by tag rather than clearing everything.
+ - A hot key expires under load and every request recomputes it at once.
+ - Adding HTTP cache headers, a cache warmer, or clearing pools on deploy.
## Default workflow
- 1. Define async contract and delivery semantics.
- 2. Implement idempotent handlers and routing strategy.
- 3. Configure retries, failure transport, and observability.
- 4. Validate success/failure replay scenarios.
+ 1. Identify what is recomputed and how often, and whether it can go stale.
+ 2. Pick the pool and adapter for the access pattern and the deployment shape.
+ 3. Read through `CacheInterface::get()` with an explicit expiry.
+ 4. Tag every entry by the data it derives from, and invalidate by tag on write.
+ 5. Enable early expiration on keys whose recomputation is expensive.
## Guardrails
- - Assume at-least-once delivery, not exactly-once.
- - Keep handlers deterministic and side-effect aware.
- - Surface poison-message handling strategy.
+ - Set an expiry on every entry. An entry without one never leaves the pool.
+ - Never put user input in a cache key unhashed, and never put secrets in one.
+ - Invalidate by tag, not by clearing the pool: a full clear is a cold start.
+ - A cached value is stale by definition. Do not cache what must be exact.
+ - Tag invalidation needs a tag-aware adapter, so decide it when configuring the pool.
## Progressive disclosure
- Use this file for execution posture and risk controls.
- Open references when deep implementation details are needed.
## Output contract
- - Async config/handlers updated.
- - Retry/failure policy decisions.
- - Operational validation evidence.
+ - Pool and adapter configuration, with the expiry chosen for each entry.
+ - The tag map: which write invalidates which tags.
+ - Stampede protection where recomputation is expensive.
+ - Evidence that a write invalidates what it should.
## References
- `reference.md`
- `docs/complexity-tiers.md`