This Github Action adds support for removing unused dependencies from build caches.

In a nutshell, spend some time to clean up the cache, spend less time on cache restore and save. Note that Github deletes caches after a week, so this action is best suited for project under constant development, i.e. over time accumulating a lot of outdated dependencies from previous builds.

Supported build systems:

• Maven
• Gradle
• NPM

Run the skjolber/tidy-cache-github-action action after the cache restore step, and only whenever the cache will be saved again (i.e. when actions/cache is not able to restore its primary key).

Maven example:

    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Cache local Maven repository
        uses: actions/cache@v2
        id: maven-cache
        with:
          path: ~/.m2/repository
          key: ${{ runner.os }}-maven-v1-${{ hashFiles('**/pom.xml') }}
          restore-keys: |
            ${{ runner.os }}-maven-v1-
      - name: Remove unused dependencies
        uses: skjolber/tidy-cache-github-action@v1
        if: steps.maven-cache.outputs.cache-hit != 'true'
      - name: Your build here
        run: mvn verify

The action autodetects which cleanups to run by checking for the existence of cache folders (and runs them in parallel).

While NPM has a built-in command for removing unused depenencies, for Maven and Gradle, things are not that simple:

• Maven: Adds instrumentation via the .mavnrc file, so to record which pom files are in use.
• Gradle: Accesses the cache journal. Uses internal classes.

So there is some risk that the cleanup logic will fail at some point in the future.

The scripts and documentation in this project are released under the MIT License

• Github Cache Action
• maven-pom-recorder
• gradle-cache-cleaner