Debug-action-cache

In modern Continuous Integration and Continuous Deployment (CI/CD) pipelines, speed is everything. Software engineering teams heavily rely on caching mechanisms to eliminate redundant steps like reinstalling vendor packages or recompiling static assets. However, when a cache breaks, developers face , corrupted dependencies , and ballooning build times .

Locate the section in the left sidebar and click Caches .

A debug-action-cache log says:

[debug] Restoring cache... (originally saved on windows-2022) [debug] Extracting binary: 'app.exe' -> incompatible.

Standard logs just show Received 0 of 0 artifacts . That is useless. To see the truth, you need , specifically for the cache action. debug-action-cache

Choosing how to structure your cache keys determines how often your workflows hit or miss. Cache Strategy Best Used For Core OS dependencies, system-wide runtimes. High reuse across different feature branches. Prone to accidental pollution and bloat. Matrix Cache Multi-version testing (Node 18 vs Node 20). Completely isolates different execution environments. Multiplies storage usage across the repository. Branch-Isolated Feature-specific feature builds. Prevents main branch code from being overwritten. Fresh branches suffer a slow first build. 💡 Pro Tips for Maintaining High Cache Hit Rates

Maximizing Build Efficiency: A Deep Dive into debug-action-cache

What kind of report are you looking for?

This exposes the communication between the runner and the remote cache storage, showing you if the network is failing or if the key lookup is returning a "404 Not Found." The "Cache-Hit" Checklist Locate the section in the left sidebar and click Caches

Look for the [debug] restoreKeys line:

If you suspect specific rules are not caching, use aquery to examine how Bazel constructs the action graph 2.2.2 . bazel aquery 'mnemonic("CppCompile", //your:target)' Use code with caution.

bazel build //target --execution_log_compact_file=/tmp/exec1.log

For deep issues (like file permissions or path mismatches), use a tool like Action-Debugger Standard logs just show Received 0 of 0 artifacts

[debug] Resolved path: 'node_modules' -> '/home/runner/work/app/node_modules' [debug] Path exists: true [debug] Contents: [ 'react', 'lodash', '.bin' ]

This forces the cache engine to print exact compression statistics, network download speeds, and key-matching logic directly into the console. Step 2: Audit Cache Key Hashes

What (Node/NPM, Python, Docker, Go) are you currently trying to cache?

Exporting cache hierarchy as a directed acyclic graph (DAG) to identify which dependency layer caused the invalidation. 4. Implementation Case Study