Using a Git Branch as a Source for Terraform Modules

TLDR

To use a Git branch as the source for a Terraform module, specify the branch name in the source argument using the ?ref= query parameter. This allows you to manage module versions dynamically.

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Terraform modules are reusable configurations that simplify infrastructure management. By using a Git branch as the source for a module, you can manage versions and collaborate on module development effectively. This guide will show you how to use a Git branch as a module source.

Why Use a Git Branch as a Module Source?

• Version Control: Use branches to manage different versions of a module.
• Collaboration: Share module updates with your team during development.
• Flexibility: Test changes in a branch before merging them into the main branch.

Specifying a Git Branch as a Module Source

Use the source argument in your module block to specify the Git repository and branch. The ?ref= query parameter allows you to select a specific branch.

Example: Using a Git Branch

module "example" {
  source = "git::https://github.com/your-org/your-module.git?ref=feature-branch"

  # Module inputs
  region = "us-east-1"
  name   = "example"
}

In this example, the feature-branch branch is used as the source for the module.

Using SSH for Private Repositories

If the repository is private, use the SSH URL instead of HTTPS.

Example: Using SSH

For private repositories, you can specify the source using SSH:

module "example" {
  source = "git::ssh://[email protected]/your-org/your-module.git?ref=feature-branch"

  # Module inputs
  region = "us-east-1"
  name   = "example"
}

Ensure your SSH key is configured for authentication.

Best Practices

• Pin to Specific Branches: Use branches for development and testing, but pin to tags for production.
• Use Version Tags: Prefer version tags for stable releases to ensure consistency.
• Document Module Inputs: Clearly document the inputs and outputs of your module.
• Test Changes: Validate module changes in a non-production environment before merging them into the main branch.

By using a Git branch as a source for Terraform modules, you can streamline development workflows and manage module versions effectively.