act-docker-setup

# Act - Docker Configuration and Setup

Use this skill when configuring Docker for act, choosing runner images, managing container resources, and optimizing Docker performance for local GitHub Actions workflow testing.

## Runner Images

### Image Size Categories

Act supports three image size categories:

| Size | Image | Tools | Use Case |
|------|-------|-------|----------|
| Micro | `node:16-buster-slim` | Minimal | Simple Node.js workflows |
| Medium | `catthehacker/ubuntu:act-*` | Common tools | Most workflows |
| Large | `catthehacker/ubuntu:full-*` | Everything | Maximum compatibility |

### Official catthehacker Images

```bash
# Latest Ubuntu (22.04)
act -P ubuntu-latest=catthehacker/ubuntu:act-latest

# Specific Ubuntu versions
act -P ubuntu-22.04=catthehacker/ubuntu:act-22.04
act -P ubuntu-20.04=catthehacker/ubuntu:act-20.04

# Full images (larger, more tools)
act -P ubuntu-latest=catthehacker/ubuntu:full-latest
act -P ubuntu-22.04=catthehacker/ubuntu:full-22.04

# Runner images (closest to GitHub)
act -P ubuntu-latest=catthehacker/ubuntu:runner-latest
```

### Language-Specific Images

```bash
# Node.js
act -P ubuntu-latest=node:20
act -P ubuntu-latest=node:20-alpine

# Python
act -P ubuntu-latest=python:3.12
act -P ubuntu-latest=python:3.12-slim

# Go
act -P ubuntu-latest=golang:1.22
act -P ubuntu-latest=golang:1.22-alpine

# Ruby
act -P ubuntu-latest=ruby:3.3
act -P ubuntu-latest=ruby:3.3-alpine
```

## Platform Configuration

### .actrc Configuration

Create `.actrc` in project root for persistent settings:

```
# Default platform images
-P ubuntu-latest=catthehacker/ubuntu:act-latest
-P ubuntu-22.04=catthehacker/ubuntu:act-22.04
-P ubuntu-20.04=catthehacker/ubuntu:act-20.04

# Reuse containers
--reuse

# Container options
--container-architecture linux/amd64
--container-daemon-socket -

# Resource limits
--container-cap-add SYS_PTRACE
--container-cap-add NET_ADMIN
```

### Per-Workflow Configuration

Create `.github/workflows/.actrc` for workflow-sp