devenv-migration

# devenv Migration Skill

Convert nix-shell projects to devenv or create new devenv environments with declarative configuration for languages, services, and processes.

**Official devenv.nix Options Reference**: https://github.com/cachix/devenv/blob/main/docs/src/reference/options.md

## What is devenv?

**devenv** is a declarative development environment tool built on Nix that provides:

- **Integrated service management**: PostgreSQL, Redis, MySQL run as managed processes
- **Process orchestration**: Dev servers, watchers, and workers in one configuration
- **Better isolation**: Services use project-local data directories
- **Simplified setup**: Single `devenv.nix` replaces multiple configuration files
- **Pre-commit integration**: Declarative git hooks (170+ built-in)
- **Task system**: Define build, test, and deployment tasks

## When to Use This Skill

Trigger this skill when users:
- Want to migrate from nix-shell to devenv
- Need help configuring devenv.nix
- Ask about setting up languages (Python, JavaScript, Elm, Go, Rust)
- Need service configuration (PostgreSQL, Redis, MySQL, etc.)
- Want to configure processes or tasks
- Have issues with devenv setup
- Ask about converting process-compose.yml to devenv
- Need help with platform-specific issues (Linux patchelf, macOS frameworks)

## Quick Start

### New Project

```bash
# Install devenv
nix profile install nixpkgs#devenv

# Initialize in project directory
cd your-project
devenv init

# Enter environment
devenv shell

# Start services and processes
devenv up
```

### Migration from nix-shell

See [Migration Guide](./references/migration-guide.md) for detailed conversion patterns.

**Quick conversion:**
1. Read existing shell.nix/default.nix
2. Map buildInputs to languages.* and packages
3. Convert shellHook to enterShell
4. Replace manual service setup with services.*
5. Convert process-compose.yml to processes
6. Test with `devenv shell` and `devenv up`

## Core Concepts

### Configuration Structure

```n