Composal Disk Volume

Persist dependency directories across Composal GitHub Actions jobs. Both composal-x64-2x and composal-x64-4x use the same repository-scoped storage.

jobs:
  test:
    runs-on: [composal-x64-4x]
    steps:
      - uses: actions/checkout@v4
      - uses: composalai/disk-volume@v1
        id: npm-disk
        with:
          key: npm-store-v1
          path: ~/.npm
      - run: npm ci
      - run: npm test

key identifies a persistent directory within your GitHub App installation and repository. path is an empty absolute, workspace-relative, or ~/ directory. The action outputs cache-hit and the absolute mounted path. Prefer stable keys for package download stores (~/.npm, a pnpm store, Cargo registry/git caches); package managers check the package versions and integrity. Use distinct keys for incompatible platforms or toolchains.

Each job restores its own copy of a trusted snapshot. Concurrent jobs never share a live directory. Only successful push, schedule, or workflow_dispatch jobs on the repository's default branch publish an updated snapshot. Pull requests and other branches can restore and modify their copy, but their changes are discarded. When trusted jobs publish the same key concurrently, the last completed publication becomes the snapshot for future jobs; changes are not merged.

Limits: five disk mounts per job, 32 keys and 10 GiB of published data per repository. Snapshots unused for seven days are not restored. Superseded snapshots are removed after seven days and abandoned job clones after a day. Current snapshot metadata remains reserved until the key is reused; this first release has no user-facing disk deletion interface.

Dependency disks are opt-in. Ordinary actions/cache and language setup actions continue using GitHub's cache backend.