Debug-action-cache -

At its core, the action uses a you provide to uniquely identify a cache. When you run a workflow, the action attempts to restore a cache by matching this key. If found, the cached files are downloaded to your specified path. For example, a typical configuration uses:

It typically involves:

If you see Validation: SHA256 mismatch , your cache is corrupted (rare, but happens with network proxies). The solution is to delete the cache key.

When your pipelines slow down due to caching faults, use these three diagnostic layers to uncover the root cause. 1. Enable Verbose Engine Diagnostics debug-action-cache

: Utilizes actions like actions/cache to store npm nodes, Ruby gems, or Cargo registries based on explicit cache keys.

The first and most critical step in your debugging journey is to enable the secret, detailed logging that GitHub Actions normally hides from you. There are two primary levels of debug logging you need to know about.

This guide will provide a thorough, practitioner-focused deep dive into the debug-action-cache process. You’ll learn not only how to enable and interpret hidden debug logs, but also how to use this newfound insight to solve the most common—and most frustrating—cache-related failures, from mysterious version mismatches to quota limit errors and silent save failures. At its core, the action uses a you

Set the CI_DEBUG_TRACE variable to true in your .gitlab-ci.yml .

Add to your workflow file:

For the ultimate debugging environment, you can test your caching logic locally using the nektos/act tool. act allows you to run GitHub Actions on your local machine, which is perfect for rapid iteration without consuming GitHub Actions minutes or polluting your repository history with test commits. For example, a typical configuration uses: It typically

The first line of defense is . GitHub Actions supports two environment variables that unlock detailed logs:

: Cache not found for key: linux-npm-xyz123