Use case: (PHP) composer cache about cache

[teohhanhui]

If we're able to use something like this, it'd work nicely:

    - name: Cache composer packages
      uses: actions/cache@preview
      with:
        path: ~/.composer/cache/files
        key: composer-${{ date('yyyy') }}-${{ date('mm') }}-${{ date('dd') }}-${{ github.sha }}
        restore-keys: |
          composer-${{ date('yyyy') }}-${{ date('mm') }}-${{ date('dd') }}-
          composer-${{ date('yyyy') }}-${{ date('mm') }}-
          composer-${{ date('yyyy') }}-
          composer-

[teohhanhui]

Or does the fallback order already use the most recent key first?

[joshmgross]

Hey @teohhanhui, I see you closed this issue, did you get this figured out?

[teohhanhui]

I think it works just fine assuming that the fallback always uses the most recent cache key (so there's no need for a date function, though that might still be useful for other use cases).

But indeed it'd be great to have an additive cache (updating an existing cache key). In the case of composer, it means we could share the same cache in different jobs with different stability level for the dependencies (e.g. normal, lowest deps, and unstable).

[dhadka]

@teohhanhui You are correct, the fallback selects the most recently created cache that matches the restore key prefix.

[joshmgross]

We should have docs coming soon with more details. If you want the date, you do something with action outputs like:

    - name: Set an output
      id: get-date
      run: |
        echo ::set-output name=date::$(/bin/date -u "+%Y%m%d")
    - name: Use the output
      run: |
        echo 'The output date is ${{ steps.get-date.outputs.date }}'

see the docs on outputs.

But as @dhadka said, you should be fine the fallback as is