Tuist module cache for Buildkite

Keep Tuist's local cache across jobs on Tuist macOS runners. Every tuist command the step runs reads and writes its cache on storage that Tuist restores into the next job: module cache binaries, along with compiled manifests, plugins and selective testing results. Binaries the job finds locally do not have to be downloaded again.

steps:
  - label: Test
    agents:
      queue: tuist-macos
    plugins:
      - tuist/module-cache#v1: ~
    command: |
      tuist generate --no-open
      tuist test

The pre-command hook sets TUIST_XDG_CACHE_HOME to the restored cache and TUIST_CACHE_MAX_BYTES to its share of the storage, so the Tuist CLI evicts the least recently used binaries before the cache fills up. Authenticate and configure the module cache as usual; the plugin only decides where its local copy lives.

Successful webhook and schedule builds of your pipeline's repository save their changes, including its pull requests. Fork pull requests, tags and builds started from the API or the dashboard use the cache but never save. To save only from some branches, limit them on the runner profile; see Choose which branches save. Directories you keep with the tuist/cache-volume plugin are separate.

The cache starts at 20gb. Set size to give it another capacity, a whole number of GB from 1gb to 100gb:

    plugins:
      - tuist/module-cache#v1:
          size: 50gb

The Tuist CLI keeps the cache within whatever its capacity is. A larger size grows the cache, keeping its contents, from its next build. A smaller one applies after the cache is next cleared or expires. Runner images without size support keep the current size and warn.

On agents that are not Tuist macOS runners the hook does nothing. If the runner could not restore the cache, the hook warns and the build runs with an empty one; it never fails the step.

This plugin's distribution repository is tuist/module-cache-buildkite-plugin. SOURCE_COMMIT records its monorepo source.