munkisrv

munkisrv is a Go web server for serving Munki repositories. It comes with built-in support for generating AWS CloudFront pre-signed URLs.

Overview

munkisrv is a lightweight HTTP server designed to serve Munki repositories. It provides:

• Static file serving for Munki repository catalogs, manifests, and icons
• AWS CloudFront signed URL generation for secure package downloads
• Health check endpoint for monitoring
• Graceful shutdown handling

Features

• Munki Repository Serving: Serves embedded Munki repository files including catalogs, manifests, client resources, and icons
• CloudFront Integration: Generates signed URLs for package downloads through AWS CloudFront for enhanced security and performance
• Health Checks: Built-in health check endpoint at /healthz
• Graceful Shutdown: Proper signal handling for clean server shutdown
• Configurable: YAML-based configuration with environment variable overrides

Architecture

The server provides three main endpoints:

• GET /healthz - Health check endpoint
• GET /repo/* - Serves static Munki repository files
• GET /repo/pkgs/* - Redirects to signed CloudFront URLs for package downloads

Configuration

Create a config.yaml file with the following structure:

# Server configurations
server:
  host: "localhost"
  port: ":3000"

# CloudFront configurations
cloudfront:
  url: "https://your-distribution.cloudfront.net"
  key_id: "YOUR_CLOUDFRONT_KEY_ID"
  private_key: |
    -----BEGIN PRIVATE KEY-----
    YOUR_PRIVATE_KEY_CONTENT_HERE
    -----END PRIVATE KEY-----

Environment variables

Configuration can be overridden using environment variables with the prefix ENV_:

• ENV_SERVER_HOST - Server host
• ENV_SERVER_PORT - Server port
• ENV_CLOUDFRONT_URL - CloudFront distribution URL
• ENV_CLOUDFRONT_KEY_ID - CloudFront key pair ID
• ENV_CLOUDFRONT_PRIVATE_KEY - CloudFront private key

Installation

1. Clone the repository

2. Build the binary:

   go build ./cmd/munkisrv
   

Usage

Run the server with a configuration file:

./munkisrv -c path/to/config.yaml

The server will start on the configured port (default: :3000) and serve:

• Static repository files at /repo/*
• Package downloads via signed CloudFront URLs at /repo/pkgs/*
• Health checks at /healthz

Send a test request:

curl http://127.0.0.1:3000/repo/catalogs/all

Configure munki to connect:

sudo defaults write /Library/Preferences/ManagedInstalls.plist SoftwareRepoURL http://127.0.0.1:3000/repo

Dependencies

• github.com/aws/aws-sdk-go-v2/feature/cloudfront/sign - CloudFront URL signing
• github.com/go-chi/chi/v5 - HTTP router and middleware
• github.com/spf13/viper - Configuration management

Security

The server uses AWS CloudFront signed URLs to secure package downloads. Private keys are parsed and validated at startup to ensure proper cryptographic operations.

This service does not provide authentication or authorization — users are expected to handle both outside of this web service (e.g., via a reverse proxy, network policy, or service mesh)

Health monitoring

The /healthz endpoint checks the availability of the embedded Munki repository by attempting to open the catalogs/all file. This ensures the server is properly configured and the repository is accessible.

Munki integration

This server is designed to work with the Munki open-source software deployment system for macOS. It serves the repository structure that Munki clients expect:

• Catalogs: Software catalog definitions
• Manifests: Client-specific software manifests
• Icons: Application icons for the Munki client GUI
• Client Resources: Additional resources for Munki clients
• Packages: Software packages (served via CloudFront)

Munki client configuration

At a minimum, configure your munki client to access the /repo path at your domain.

sudo defaults write /Library/Preferences/ManagedInstalls.plist SoftwareRepoURL https://<yourdomain>/repo

Ensure munki is configured to follow HTTP redirects.

sudo defaults write /Library/Preferences/ManagedInstalls.plist FollowHTTPRedirects https