setup-c3x

This action now lives in c3xdev/c3x and on the GitHub Marketplace as C3X Cost Estimation. New workflows should use c3xdev/c3x@v0. Existing c3xdev/setup-c3x@v1 workflows keep working unchanged: this repository is a thin wrapper around c3xdev/c3x@v0 and gets every fix to it automatically.

GitHub Action for c3x: cloud cost estimation for Terraform, OpenTofu and CloudFormation. It posts the cost change of every pull request as a comment. Free and open source, no API key, no secrets.

Quick start

name: Cost estimation
on: [pull_request]
permissions:
  pull-requests: write
  contents: read
jobs:
  c3x:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: c3xdev/setup-c3x@v1
        with:
          path: .

The comment shows the monthly cost before and after the pull request and the change per resource:

Baseline	New	Change
$1038.32/mo	$1318.64/mo	🔺 +$280.32

Gates

      - uses: c3xdev/setup-c3x@v1
        with:
          path: .
          budget-delta: "50"   # fail if this PR adds more than $50/mo
          budget: "5000"       # fail if the monthly total exceeds $5,000
          strict: true         # fail if any line rests on an assumption

Plan JSON

If your pipeline already runs terraform plan, give c3x the plan. It has the real values of data sources and computed attributes:

      - run: terraform plan -out=tfplan && terraform show -json tfplan > plan.json
      - uses: c3xdev/setup-c3x@v1
        with:
          path: plan.json

Install only

Leave path empty to install the CLI and run it yourself:

      - uses: c3xdev/setup-c3x@v1
      - run: c3x estimate --path . --format markdown

Inputs

Input	Description	Default
version	c3x version, e.g. 0.3.12	latest
path	Directory, plan JSON or CloudFormation template. Empty installs only.
comment	Post or update the PR comment	true
budget	Fail when the monthly total exceeds this (0 disables)	0
budget-delta	Fail when the PR increases the total by more than this (0 disables)	0
strict	Fail when any line rests on an assumption	false
currency	Display currency (USD, EUR, GBP, …)	USD
untrusted	Untrusted-input mode: auto (forks), true, false	auto
branded-comments	Comment as the C3X Cloud app. Needs the app installed and permissions: id-token: write.	false
show-all-projects	Deprecated, ignored

The token output is kept for older workflows and returns the workflow's GITHUB_TOKEN.

License

Apache-2.0