Design Document for Automating macOS Installers (.pkg and .dmg)

1. Title and Overview

Project Name: macOS Installer Automation

Objective:

Develop a fully automated pipeline for creating .pkg and .dmg installers for macOS applications. The project will also explore the distribution of apps using Homebrew formulas, ensuring compatibility across multiple macOS versions.

2. Goals and Non-Goals

Goals:

• Automate the creation of .pkg and .dmg installers.
• Ensure installers are compatible with macOS versions like Ventura, Sonoma, and Sequoia.
• Create and publish Homebrew formulas for streamlined app distribution.

Non-Goals:

• Developing a custom macOS installer tool from scratch.
• Integration with app stores or third-party distribution platforms.

3. Design Overview

• Input: Compiled macOS application binary and resources.
• Output:
  • .pkg installer for managed installations.
  • .dmg image for drag-and-drop installations.
  • Homebrew formula for command-line distribution.
• Architecture:
  • Build Automation:
    • Automate the build process using pkgbuild and dmgcanvas.
  • Validation and Testing:
    • Verify installers across multiple macOS versions.
  • Distribution:
    • Use Homebrew to simplify CLI-based installation.

4. System Design

4.1 Components

• Installer Builder:
  • Automates the creation of .pkg using pkgbuild and .dmg using dmgcanvas or create-dmg.
• Configuration Manager:
  • Stores metadata like app name, version, package identifier, and installation scripts.
• Validator:
  • Tests installer compatibility and correctness across macOS versions.
• Homebrew Formula Generator:
  • Automates the creation of Homebrew formulas for CLI-based app distribution.

4.2 Workflow

1. Preparation:
   • Collect application binaries, resources, and metadata.
   • Write pre-install and post-install scripts for .pkg.
2. Build Process:
   • Use pkgbuild to generate .pkg files with necessary permissions and configurations.
   • Use dmgcanvas or create-dmg to generate .dmg images.
3. Validation:
   • Run installers on different macOS versions to verify compatibility.
   • Automate validation using macOS VMs or CI tools like GitHub Actions.
4. Homebrew Integration:
   • Generate and publish Homebrew formulas.
5. Distribution:
   • Host .pkg, .dmg, and Homebrew formulas on a public or private server.

5. API and Data Structures

5.1 Configuration File

• InstallerConfig.json:

{
    "appName": "SampleApp",
    "version": "1.0.0",
    "identifier": "com.sample.app",
    "installScripts": {
        "preInstall": "scripts/preinstall.sh",
        "postInstall": "scripts/postinstall.sh"
    },
    "outputDir": "./dist"
}

5.2 Interfaces

• InstallerBuilder:

def create_pkg(config_file: str) -> str:
    """Generate a .pkg installer based on configuration."""
def create_dmg(config_file: str) -> str:
    """Generate a .dmg installer based on configuration."""

• Validator:

def validate_installer(installer_path: str, macos_versions: List[str]) -> bool:
    """Validate installer compatibility across macOS versions."""

• Homebrew Formula Generator:

def generate_formula(config_file: str, repo_url: str) -> str:
    """Create a Homebrew formula for distribution."""

6. Installer Automation Tools

• pkgbuild: Official tool to package software into .pkg format.
• dmgcanvas/create-dmg: Utilities for creating .dmg images with drag-and-drop interfaces.
• Homebrew: Package manager for macOS to distribute applications.

7. Multiversion Testing

• Testing Matrix: Validate installers on Ventura, Sonoma, and Sequoia using virtualization or cloud-based CI tools.
• Automated Test Scenarios:
  • Install and uninstall workflows.
  • Compatibility with system preferences (e.g., permissions).
  • Edge cases like corrupted files or missing dependencies.

8. Best Practices

• Security: Sign and notarize installers to meet Apple’s security requirements.
• Testing: Test installers on clean macOS installations to simulate real user environments.
• Documentation: Provide clear instructions for both .pkg and .dmg installations.

9. Example Workflow

1. Prepare Metadata:
   • Create InstallerConfig.json with app details.
2. Automate Build:
   • Run a Python script to execute pkgbuild and dmgcanvas commands.
3. Validate:
   • Use a CI tool to run tests on different macOS versions.
4. Distribute:
   • Upload .pkg and .dmg to a server.
   • Publish Homebrew formula to a public repository.

10. Testing Strategy

Unit Testing:

Validate individual scripts (e.g., pre-install scripts).

Integration Testing:

Test end-to-end installer generation and installation workflows.

Performance Testing:

Measure installer build times for large applications.