music_library/backlog/tasks/ml-151 - Document-Assets.Cache-TTL-and-cache-invalidation-strategy.md

id, title, status, assignee, created_date, labels, dependencies, references, priority

id	title	status	assignee	created_date	labels	dependencies	references	priority
ML-151	Document Assets.Cache TTL and cache invalidation strategy	To Do		2026-04-30 10:48	documentation assets		lib/music_library/assets/cache.ex	low

Description

Assets.Cache (lib/music_library/assets/cache.ex) uses an ETS table with TTL for caching binary asset data. When assets are updated (e.g., a new cover is uploaded), the cache relies on TTL-based expiry — there is no explicit invalidation.

The TTL duration and the rationale for TTL-only invalidation (vs. explicit purge) are not documented in the module or in the architecture docs.

Add a @moduledoc to Assets.Cache that explains:

• The TTL value and where it's configured
• The invalidation strategy (TTL-based expiry) and why explicit invalidation is/isn't needed
• Update docs/architecture.md if the design decision has architectural relevance

Acceptance Criteria

• #1 Assets.Cache @moduledoc documents the TTL value and where it is configured
• #2 The invalidation strategy (TTL-based expiry) is explained with rationale
• #3 Any architectural implications are captured in docs/architecture.md