Dagger Action for GitHub

An alternate GitHub Action for running Dagger with better caching support.

Important

This action is only for Linux runners.

Usage Examples

Basic Usage

- name: Run Dagger
  uses: memospot/action-dagger@v1
  with:
    module: github.com/shykes/daggerverse/hello
    call: hello --greeting Hola --name Jeremy

With Version Pinning

- name: Run Dagger with specific version
  uses: memospot/action-dagger@v1
  with:
    version: '0.19.11'  # Pin to specific version
    module: github.com/shykes/daggerverse/hello
    call: hello

With Caching Disabled

- name: Run Dagger without caching
  uses: memospot/action-dagger@v1
  with:
    cache-builds: false
    module: github.com/shykes/daggerverse/hello
    call: hello

dagger shell

- name: Dagger Shell
  uses: memospot/action-dagger@v1
  with:
    shell: container | from alpine | with-exec echo,"hello, world!" | stdout

dagger run

- name: Integration Test
  uses: memospot/action-dagger@v1
  with:
    workdir: db-service
    verb: run
    args: node build.js

Inputs

Key	Description	Required	Default
version	Dagger CLI version (semver or 'latest')	false	'latest'
cache-builds	Enable Dagger build cache persistence	false	true
cache-binary	Cache Dagger binary to avoid re-downloading	false	true
cache-key	Custom cache key (e.g. foo-${{ github.run_id }})	false	''
cache-mode	Cache extraction mode (auto, direct, container)	false	'auto'
cache-timeout	Timeout in minutes for cache save operations (0=disable)	false	'10'
dagger-flags	Dagger CLI Flags	false	'--progress plain'
verb	CLI verb (call, run, download, up, functions, shell, query)	false	'call'
workdir	Working directory for Dagger CLI	false	'.'
cloud-token	Dagger Cloud Token	false	''
module	Dagger module to call (local or Git)	false	''
args	Arguments to pass to CLI	false	''
call	Function and arguments for dagger call	false	''
shell	Function and arguments for dagger shell	false	''
summary-path	File path to write job summary	false	''
enable-github-summary	Write summary to GITHUB_STEP_SUMMARY	false	false

Outputs

Key	Description
dagger-version	The installed Dagger version
cache-hit	Whether binary was restored from cache
binary-path	Path to the installed Dagger binary
output	Standard output of Dagger command
trace-url	Dagger Cloud trace URL

Cache Strategy

Binary Cache

The Dagger binary is cached using GitHub Actions tool-cache by tool/version/arch lookup.

• Tool name: dagger
• Version: resolved Dagger version (including latest resolution)
• Arch: runner architecture (for example amd64 or arm64)

Build Cache

Dagger build cache persists the engine state volume to GitHub Actions Cache:

• Default Behavior: "Rolling cache" strategy.
  • Save Key: dagger-<arch>-<run_id> (always unique, forcing a save)
  • Restore Key: dagger-<arch>- (matches most recent previous run)
• This ensures that every run saves its state on top of the previous one, maximizing cache freshness.

Custom Cache Keys

You can override the default key using cache-key. To maintain the rolling cache behavior (recommended), ensure your key ends with a unique component like ${{ github.run_id }}.

- name: Run Dagger with custom key
  uses: memospot/action-dagger@v1
  with:
    # Use a custom prefix but keep the rolling behavior
    cache-key: 'my-project-v2-${{ runner.os }}-${{ github.run_id }}'
    module: github.com/shykes/daggerverse/hello
    call: hello

The action will automatically derive the restore key by stripping the last hyphen-delimited segment (e.g., my-project-v2-${{ runner.os }}).

Cache Invalidation

To invalidate the cache, simply change the prefix of your cache-key (e.g., from v1 to v2). If using defaults, the action handles versioning internally.

Cache Modes

The cache-mode input controls how the Dagger engine state is cached:

• auto (default): Automatically tries direct mode first, then falls back to container if it fails. This is the recommended mode for most users.
• direct: Uses direct volume mounting for faster cache operations. May encounter permission issues on some runners.
• container: Uses a busybox container to create/restore tarballs. Slower and with higher disk usage peak, but more reliable.

Cache failures in any mode are soft-failures - the action will emit a warning but continue execution.

- name: Run Dagger with explicit cache mode
  uses: memospot/action-dagger@v1
  with:
    cache-mode: direct  # Force direct mode (faster, may fail on some runners)
    module: github.com/shykes/daggerverse/hello
    call: hello

Migration Guide

From dagger/dagger-for-github

This action is a TypeScript rewrite of dagger/dagger-for-github with new caching capabilities:

1. Update your workflow:

   # Before
   uses: dagger/dagger-for-github@v7
   
   # After
   uses: memospot/action-dagger@v1

2. New features available:

   • Binary caching: cache-binary: true
   • Build caching: cache-builds: true
   • Version output: ${{ steps.dagger.outputs.dagger-version }}

3. Backward compatibility: All existing inputs continue to work

Troubleshooting

Cache Not Working

1. Check that cache-builds is set to true (default)
2. Verify GitHub Actions Cache is available in your repository
3. Check workflow logs for cache restore/save messages

Binary Not Found

1. Check the binary-path output
2. Verify platform support. Only Linux is supported.
3. Check network access to dl.dagger.io

Version Issues

1. Use semantic version format: 0.15.0 or v0.15.0
2. Use latest for the most recent release
3. Check Dagger releases for available versions

License

BSD-2-Clause-Patent

Contributing

See CONTRIBUTING.md for development setup, project structure, and release process.