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GitHub Action

Run Infracost

v0.3.0 Latest version
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Run Infracost

Show cloud cost estimate changes from Terraform in pull requests

Installation

Copy and paste the following snippet into your .yml file.

- name: Run Infracost
  uses: infracost/infracost-gh-action@v0.3.0
Learn more about this action in infracost/infracost-gh-action
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Infracost GitHub action

This action runs Infracost against the master branch and the pull request whenever a Terraform file changes. It automatically adds a pull request comment showing the cost estimate difference (similar to git diff) if a percentage threshold is crossed.

Example screenshot

Inputs

tfjson

Optional Path to Terraform plan JSON file.

tfplan

Optional Path to Terraform plan file relative to 'tfdir'. Requires 'tfdir' to be set.

tfdir

Optional Path to the Terraform code directory (default is current working directory).

tfflags

Optional Flags to pass to the 'terraform plan' command.

percentage_threshold

Optional The absolute percentage threshold that triggers a pull request comment with the diff. Defaults to 0, meaning that a comment is posted if the cost estimate changes. For example, set to 5 to post a comment if the cost estimate changes by plus or minus 5%.

pricing_api_endpoint

Optional Specify an alternate price list API URL (default is https://pricing.api.infracost.io).

Environment variables

The AWS secrets mentioned below are used by terraform init and plan commands. As mentioned in the Infracost FAQ you can run infracost in your terraform directories without worrying about security or privacy issues as no cloud credentials, secrets, tags or Terraform resource identifiers are sent to Infracost's cloud pricing API. Infracost does not make any changes to your Terraform state or cloud resources.

Standard Terraform env vars can also be added if required, e.g. TF_CLI_ARGS.

INFRACOST_API_KEY

Required To get an API key download Infracost and run infracost register.

AWS_ACCESS_KEY_ID

Required AWS access key ID is used by terraform init and plan commands.

AWS_SECRET_ACCESS_KEY

Required AWS secret access key is used by terraform init and plan commands.

GITHUB_TOKEN

Required GitHub token used to post comments, should be set to ${{ secrets.GITHUB_TOKEN }} to use the default GitHub token available to actions.

Outputs

master_monthly_cost

The master branch's monthly cost estimate.

pull_request_monthly_cost

The pull request's monthly cost estimate.

Usage

  1. Add repo secrets for INFRACOST_API_KEY, AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY to your GitHub repo.

  2. Create a new file in .github/workflows/infracost.yml in your repo with the following content. Use the Inputs and Environment Variables section above to decide which env and with options work for your Terraform setup. The following example uses tfdir and tfflags so it would be the equivalent of running terraform -var-file=myvars.tfvars inside the directory with the terraform code.

on:
  push:
    paths:
    - '**.tf'
    - '**.tfvars'
    - '**.tfvars.json'    
jobs:
  infracost:
    runs-on: ubuntu-latest
    name: Show infracost diff
    steps:
    - name: Checkout master branch
      uses: actions/checkout@v2
      with:
        ref: master
        path: master
    - name: Checkout pull request branch
      uses: actions/checkout@v2
      with:
        ref: ${{ github.event.pull_request.head.sha }}
        path: pull_request
    - name: Run infracost diff
      uses: infracost/infracost-gh-action@master
      env:
        INFRACOST_API_KEY: ${{ secrets.INFRACOST_API_KEY }}
        AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
        AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      with:
        tfdir: PATH/TO/CODE
        tfflags: -var-file=myvars.tfvars

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

License

Apache License 2.0

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