Using the GitHub Actions cache with npx and no package.json

Some of my repositories have GitHub Actions workflows that execute commands using npx, for example my graphql-scraper repo using npx to install and run the get-graphql-schema tool:

npx get-graphql-schema > flyctl/fly.graphql

This was downloading the package from npm every time the action ran. This feels rude! I wanted to use the actions/cache mechanism to cache the download in between runs.

One problem: the documentation for that action assumes that projects are using a package.json file which can be used as part of the cache key. But my projects don't have one of those files, they just want to use npx utilities as part of their workflows.

Here's the pattern I came up with to configure the cache:

    - uses: actions/setup-node@v2
        node-version: '14'
        cache: 'npm'
        cache-dependency-path: '**/.github/workflows/*.yml'

This is using actions/setup-node which itself can setup the cache. I'm telling it that I want to cache npm assets - which usually requires a package.json file. But it turns out you can set a custom cache-dependency-path - and in this case I'm bundling together ALL of my GitHub Actions wokflow YAML files as that cache key.

I could be more specific and indicate the exact filename of the workflow in question, but I wanted something I could copy-and-paste between projects easily.

With this in place, npx ... lines now get to reuse the previously downloaded version of the tool. The entire cache is invalidated any time any content of any of the workflow YAML files changes, which I think is fine.

Created 2022-03-22T14:57:52-07:00, updated 2022-03-22T20:54:04-07:00 · History · Edit