moon

# moon - Polyglot Monorepo Build System

moon is a Rust-based repository management, task orchestration, and build system for polyglot monorepos. It provides smart caching, dependency-aware task execution, and unified toolchain management.

> **moon v2 is now available.** Run `moon migrate v2` to migrate. See `references/v2-migration.md` for breaking changes.

## When to Use moon

- Managing monorepos with multiple projects/packages
- Orchestrating tasks across projects with dependencies
- Caching build outputs for faster CI/local builds
- Managing toolchain versions (Node.js, Rust, Python, Go, etc.)
- Generating project and action graphs

## Quick Reference

### Core Commands

```bash
moon run <target>          # Run task(s)
moon run :lint             # Run in all projects
moon run '#tag:test'       # Run by tag
moon ci                    # CI-optimized execution
moon check --all           # Run all build/test tasks
moon query projects        # List projects
moon project-graph         # Visualize dependencies
```

### Target Syntax

| Pattern        | Description                     |
| -------------- | ------------------------------- |
| `project:task` | Specific project and task       |
| `:task`        | All projects with this task     |
| `#tag:task`    | Projects with tag               |
| `^:task`       | Upstream dependencies (in deps) |
| `~:task`       | Current project (in configs)    |

### Configuration Files

| File                   | Purpose                                  |
| ---------------------- | ---------------------------------------- |
| `.moon/workspace.yml`  | Workspace settings, project discovery    |
| `.moon/toolchains.yml` | Language versions, package managers (v2) |
| `.moon/tasks/*.yml`    | Global inherited tasks (v2)              |
| `moon.yml`             | Project-level config and tasks           |

> **v2 Note:** `.moon/toolchain.yml` → `.moon/toolchains.yml` (plural), `.moon/tasks.yml` → `.moon/tasks/*.yml`

## Workspace Config