comet

README

Comet

Cosmic tool for provisioning and managing infrastructure.

Overview

Comet is a command-line interface (CLI) tool designed to streamline infrastructure provisioning and management. It provides a unified interface for handling infrastructure operations with modern tooling and practices.

Features

• 🚀 JavaScript Configuration - Define infrastructure using a familiar, powerful programming language instead of limited HCL
• 🔄 Automatic Backend Generation - Comet generates backend.tf.json files automatically based on your stack configuration
• 🔗 Cross-Stack References - Simple state() template function to reference outputs from other stacks
• 🔐 Built-in Secrets Management - Native SOPS integration for encrypted secrets in your configurations
• 📦 Component Reusability - Define components once, reuse across environments with different configurations
• 🎯 Multi-Environment Support - Manage dev, staging, production, and any other environments from a single codebase
• ⚡ Terraform/OpenTofu Integration - Works seamlessly with both Terraform and OpenTofu
• 🛠 Minimal Abstraction - Thin wrapper that doesn't hide the underlying IaC tool
• 📝 YAML Configuration - Simple comet.yaml for project-level settings
• 🌟 Template Support - Use Go templates in component configurations for dynamic values

Why Comet?

Comet fills the gap between plain Terraform/OpenTofu and heavy enterprise frameworks, offering a pragmatic solution for teams that need DRY infrastructure configurations without the overhead of complex tooling.

The Challenge

While Terraform/OpenTofu are powerful, they have limitations when managing multi-environment infrastructures:

• ❌ Backend configuration cannot be dynamic - You must use partial configuration or wrappers
• ❌ No native multi-environment patterns - Workspaces aren't suitable for production isolation
• ❌ Verbose .tfvars management - Maintaining separate variable files for each environment
• ❌ Complex cross-stack references - Manual remote state data source configuration
• ❌ Limited DRY capabilities - HCL's declarative nature makes abstraction difficult

How Comet Solves This

Comet provides:

• ✅ JavaScript-based configuration - Leverage a familiar, powerful language for infrastructure config
• ✅ Automatic backend generation - No more manual backend.tf files
• ✅ Built-in cross-stack references - Simple state() function for referencing other stacks
• ✅ SOPS integration - Native encrypted secrets support
• ✅ Clean component reuse - Share modules across environments with ease
• ✅ Minimal abstraction - Thin wrapper that doesn't hide Terraform/OpenTofu

Comparison with Alternatives

Feature	Comet	Terragrunt	Atmos	Plain OpenTofu
Config Language	JavaScript ✨	HCL + YAML	YAML 📄	HCL
Learning Curve	Moderate	Moderate	Steep	Low
Backend Config	✅ Auto-generated	✅ Native	✅ Native	❌ Manual
Cross-Stack Refs	✅ state() function	✅ Dependencies	✅ Remote state	⚠️ Manual setup
Module Reuse	✅ JavaScript logic	✅ Dependencies	✅ Imports/Mixins	⚠️ Copy-paste
Secrets Management	✅ SOPS built-in	❌ Bring your own	❌ Bring your own	❌ Manual
Templating	✅ JS template literals	⚠️ Functions	⚠️ Go templates	❌ Limited
Community Size	Small 🐭	Large 🐘	Medium 🐈	Huge 🦕
Maturity	Young	Very Mature	Mature	Stable
Opinionation	Low	Medium	Very High	Minimal
Enterprise Features	❌	✅	✅✅✅	❌
Vendor Lock-in	None	None	Cloud Posse	None
Ideal For	Small-Medium teams	Most teams	Large enterprises	Simple setups

When to Choose Comet

Choose Comet if:

• ✅ You have < 50 components across multiple environments
• ✅ Your team prefers JavaScript over YAML/HCL
• ✅ You want minimal abstraction and transparency
• ✅ You value simplicity over extensive features
• ✅ You need built-in secrets management (SOPS)
• ✅ You're comfortable maintaining a custom tool

Consider alternatives if:

• ⚠️ You need enterprise governance features (policy enforcement, compliance)
• ⚠️ You have 100+ components across multiple orgs/regions
• ⚠️ You want the most battle-tested solution (Terragrunt)
• ⚠️ You need Cloud Posse's reference architectures (Atmos)

Installation

Prerequisites

• Go 1.23 or later

Building from Source

git clone https://github.com/moonwalker/comet.git
cd comet
go build

Usage

comet [command] [flags]

For detailed command documentation, use:

comet --help

Commands

comet version

Description: Print the version.

Usage:

comet version

comet plan

Description: Show changes required by the current configuration.

Usage:

comet plan <stack> [component]

comet output

Description: Show output values from components.

Usage:

comet output <stack> [component]

comet list

Description: List stacks or components.

Usage:

comet list [stack]

comet destroy

Description: Destroy previously-created infrastructure.

Usage:

comet destroy <stack> [component]

comet clean

Description: Delete Terraform-related folders and files.

Usage:

comet clean <stack> [component]

comet apply

Description: Create or update infrastructure.

Usage:

comet apply <stack> [component]

comet export

Description: Export stack to standalone Terraform files.

Usage:

comet export <stack> [component] -o <output-dir>

Advanced Examples

Multi-Environment Setup

// stacks/shared.js
const settings = {
  project_name: 'myapp',
  domain: 'example.com',
  gcp_project: 'my-gcp-project'
}

module.exports = { settings }

// stacks/production.js
const { settings } = require('./shared.js')

stack('production', { settings })

backend('gcs', {
  bucket: 'my-terraform-state',
  prefix: `${settings.project_name}/{{ .stack }}/{{ .component }}`
})

const vpc = component('vpc', 'modules/vpc', {
  cidr_block: '10.0.0.0/16',
  region: 'us-central1'
})

const gke = component('gke', 'modules/gke', {
  network: vpc.id,
  cluster_name: `${settings.project_name}-prod`
})

Cross-Stack References

Reference outputs from other stacks:

// stacks/application.js
const webapp = component('webapp', 'modules/k8s-app', {
  // Reference infrastructure stack outputs
  cluster_endpoint: '{{ (state "infrastructure" "gke").endpoint }}',
  vpc_id: '{{ (state "infrastructure" "vpc").id }}'
})

Dynamic Provider Configuration

// Automatically generate provider configurations
append('providers', [
  `provider "google" {`,
  `  project = "${settings.gcp_project}"`,
  `  region  = "us-central1"`,
  `}`
])

Secrets Management

// Using SOPS for encrypted secrets
const db = component('database', 'modules/cloudsql', {
  password: secrets('sops://secrets.enc.yaml#/database/password'),
  admin_user: secrets('sops://secrets.enc.yaml#/database/admin_user')
})

For more examples, see the docs directory.

Configuration

Comet can be configured using comet.yaml in your project directory.

Development

Requirements

• Go 1.23+

Setup

1. Clone the repository

git clone https://github.com/moonwalker/comet.git

1. Build the project

go build

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the terms specified in the project's license file.