caching-strategies_skill

Overview

This skill implements Rails caching patterns to improve application performance and reduce DB work. It provides concrete patterns for fragment and Russian doll caching, low-level caching, HTTP caching, memoization, and cache invalidation. Use it to standardize cache keys, TTLs, and invalidation strategies across a Rails 8.1 app.

How this skill works

The skill inspects view partials, models, service/query objects, and controller actions to recommend where to apply fragment, collection, and low-level caches. It suggests cache stores and configuration for environments, generates safe cache keys and namespacing, and outlines invalidation techniques like touch: true, manual deletes, and time-based expirations. It also provides testing and monitoring guidance for hit/miss visibility.

When to use it

• Rendering expensive partials or lists that rarely change
• Optimizing nested content with Russian doll caching
• Caching expensive query results or aggregated stats
• Designing cache invalidation after model updates
• Adding HTTP cache headers or ETag/Last-Modified support
• Writing tests that assert cache behavior and invalidation

Best practices

• Prefer stable cache keys that include model id and updated_at or explicit version tokens
• Use touch: true on child models to cascade invalidation in Russian doll patterns
• Choose a cache store appropriate for environment (memory for dev, solid_cache_store or Redis for production)
• Keep TTLs conservative for dynamic data and use manual invalidation for critical updates
• Namespace keys per account/tenant and use delete_matched only with supported stores (Redis)
• Instrument cache reads/writes to monitor hit/miss rates and guide tuning

Example use cases

• Wrap an expensive event partial: cache event do ... end to avoid repeated rendering
• Cache dashboard aggregates in a service with Rails.cache.fetch and an account-scoped key
• Render a collection with cached: true so each item reuses its fragment cache
• Add touch: true to comments so updating comments invalidates the parent event fragment
• Use stale?(etag: ..., last_modified: ...) in controllers for 304 responses and CDN-friendly caching