Dagger Action for GitHub

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

This action is used in the memos-builds repository.

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 recommended rolling cache behavior, ensure your key ends with a unique component like ${{ github.run_id }}.

- name: Run Dagger with custom key
  uses: memospot/action-dagger@v1
  with:
    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.
• 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
    module: github.com/shykes/daggerverse/hello
    call: hello

Migration Guide

From dagger/dagger-for-github

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: Existing inputs continue to work

Contributing

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