act-local-testing

# Act - Local Workflow Testing

Use this skill when testing GitHub Actions workflows locally with act. This covers act CLI commands, Docker setup, debugging, and best practices for fast local iteration on CI/CD workflows.

## Installation

### macOS

```bash
brew install act
```

### Linux

```bash
curl -s https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash
```

### Windows

```bash
choco install act-cli
# or
scoop install act
```

### From Source

```bash
go install github.com/nektos/act@latest
```

## Basic Usage

### Run All Workflows

```bash
# Run workflows triggered by push event
act

# Equivalent to
act push
```

### Run Specific Events

```bash
# Pull request event
act pull_request

# Workflow dispatch
act workflow_dispatch

# Custom event
act repository_dispatch -e event.json
```

### Run Specific Workflows

```bash
# Run specific workflow file
act -W .github/workflows/ci.yml

# Run specific job
act -j build

# Run specific workflow and job
act -W .github/workflows/deploy.yml -j production
```

### List Available Workflows

```bash
# List all workflows and jobs
act -l

# List for specific event
act pull_request -l
```

## Validation and Dry Runs

### Dry Run

```bash
# Validate without executing
act --dryrun

# Show what would run
act -n

# Validate specific workflow
act --dryrun -W .github/workflows/ci.yml
```

### Graph Visualization

```bash
# Show workflow graph
act -g

# Show graph for specific event
act pull_request -g
```

## Docker Configuration

### Default Runners

Act uses Docker images to simulate GitHub's runners:

```bash
# Use default images (micro - minimal)
act

# Use medium images (more tools)
act -P ubuntu-latest=catthehacker/ubuntu:act-latest

# Use large images (most compatible)
act -P ubuntu-latest=catthehacker/ubuntu:full-latest
```

### Custom Platform Images

Create `.actrc` file in project root:

```
-P ubuntu-latest=catthehacker/ubuntu:act-latest
-P ubuntu-22.04=catthehacker/ubuntu:act-22.04
-P ubuntu-20.04=