Debug-action-cache

Caching is not "set and forget." It is a living part of your infrastructure. Every time a dependency changes, a runner OS updates, or a new developer joins the team, your cache assumptions can break.

: If the result is not in the cache (a cache miss), the system performs the action or computation. Once completed, the result is stored in the cache for future reference.

Since "debug-action-cache" typically refers to a specific utility or workflow pattern in CI/CD environments (like GitHub Actions) designed to troubleshoot caching failures, the following paper outline focuses on the technical challenges and solutions for debugging distributed action caches.

GitHub repo → Settings → Secrets and variables → Actions → New repository secret debug-action-cache

If you suspect "Ghost Caches" (caches that exist but aren't being picked up), use the GitHub CLI ( gh ) to list caches currently stored for the repo.

If a compiler includes timestamps or absolute file paths inside compiled binary outputs, the file hashes will change between identical runs. This destroys the determinism needed for remote build caches. 🛠️ Step-by-Step Guide to Debugging an Action Cache

To help troubleshoot your specific setup, please provide a few more details: Caching is not "set and forget

| Concept | Meaning | |---------|---------| | | Unique ID for a cache entry (e.g., node-cache-linux-14-abc123 ) | | Restore key | Fallback pattern to find an older cache (e.g., node-cache-linux-14- ) | | Scope | Cache is scoped to branch + workflow + (optionally) cache-version | | Save behavior | Only runs if key didn't match an existing cache |

Ensure your build actions don't access the internet or arbitrary file system locations.

Use a tool to manually query the Digest. If the Action Cache returns a result, but the ActionResult references a file hash that doesn't exist in the CAS, your cache is "orphaned." Common Culprits of Cache Issues Once completed, the result is stored in the

You usually start looking into debug-action-cache for two reasons:

- name: Cache node_modules uses: actions/cache@v3 with: path: node_modules key: $ runner.os -node-$ hashFiles('package-lock.json') env: CACHE_VERBOSE: true # Extra debug logs