hooks-infracost

Demonstrates the infracost hook kind: an after-terraform-plan hook that runs infracost breakdown against the component and renders a cost summary in the terminal.

What this shows

• kind: infracost with zero configuration — the kind's defaults supply the binary name, args, output format, failure mode, and result handler.
• Single markdown rendering used everywhere: when Atmos Pro is connected the same body is uploaded; in the terminal it renders via ui.Markdown().

Requirements

• tofu (OpenTofu) on PATH — used in place of HashiCorp Terraform.
• infracost on PATH (e.g., atmos toolchain install infracost).
• INFRACOST_API_KEY env var (free at https://www.infracost.io/) — infracost needs an API key to access its cloud-hosted pricing database. The hook config below forwards it via env:; OS environment variables also propagate automatically.
• No AWS credentials needed — the component uses dummy AWS provider config so tofu plan succeeds offline.

Run

atmos terraform plan nat-gateway -s test

Expected: terraform plan succeeds; the after-terraform-plan hook fires; infracost runs and prints a markdown cost summary showing the NAT gateway and EIP monthly costs (typically ~$32/mo + ~$3.65/mo).

Files

• atmos.yaml — Atmos config; uses command: tofu so OpenTofu acts as the terraform binary.
• stacks/deploy/test.yaml — stack with a single component and one hook.
• components/terraform/nat-gateway/ — minimal NAT gateway + EIP module.

Notes

subnet_id is a placeholder ID. We don't need a real subnet because we never apply — infracost prices resources from HCL/plan, not from live state.