github-action-tf-plan-comment

GitHub Action to make a comment on a pull request with the proposed updated terraform plan

This action takes in the terraform plan and creates a comment on the Pull Request (PR) with basic info about what the plan will create, update, replace, or delete.

Note: this action does not run terraform plan for you, you must pass in the plan as an input as well as the directory of the terraform configuration (where the plan and .terraform dir are located after terraform init).

Usage

on: pull_request
# ...
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    # ... 
    # terraform init
    # terraform plan
    - name: Comment Terraform Plan
      uses: byu-oit/github-action-tf-plan-comment@v1
      with:
        github-token: ${{ secrets.GITHUB_TOKEN }}
        working-directory: terraform-iac/dev/app # where your terraform files are
        terraform-plan-file: plan.tfplan # relative to working directory

Inputs

• github-token - (required) pass in the GitHub token to make comments on the PR
• working-directory - (optional) the directory of the terraform configuration files (defaults to .)
• terraform-plan-file - (required) Filename of the terraform plan (relative to working-directory)
• comment-title - (optional) Title for the comment this action will make on your pull request (defaults to Terraform Plan)

note: the comment-title is used to determine which PR comment to update. For instance if you have two of these actions in one PR with the same comment-title then they will both try to update the same comment.

Output

This action will create a comment on your PR like:

Terraform Plan:

will replace (delete then create) 1 resources:

• aws_security_group_rule - db_access

will delete 1 resources:

• aws_db_instance - database

[see details](link to the github action workflow)

Contributing

Hopefully this is useful to others at BYU. Feel free to ask me some questions about it, but I make no promises about being able to commit time to support it.

GitHub Actions will run the entry point from the action.yml. In our case, that happens to be /dist/index.js.

Actions run from GitHub repos. We don't want to check in node_modules. Hence, we package the app using yarn run pack. Make sure you run yarn run pack before committing/pushing.

Modifying Source Code

Just run yarn install locally. There aren't many files here, so hopefully it should be pretty straightforward.

Cutting new releases

Push your code up to a feature branch. Create a pull request to the v1 branch (if it's a non breaking change).

After it's merged into the v1 branch then, be sure to create a new GitHub release, following SemVer. Then merge v1 into master.