terraform.yml

name: "Terraform"
on:
  push:
    branches:
      - 'main'
  pull_request:
    branches:
      - 'main'
  workflow_dispatch:

concurrency: push-to-main

env:
  SOPS_AGE_KEY: ${{ secrets.SOPS_AGE_KEY }}

jobs:
  plan:
    runs-on: ubuntu-latest
    outputs:
      diff: ${{ steps.plan.outputs.diff }}
    steps:
    - name: Checkout
      uses: actions/checkout@main
    - name: Install nix
      uses: cachix/install-nix-action@master
      with:
        nix_path: nixpkgs=channel:nixos-unstable
        extra_nix_config: |
          experimental-features = nix-command flakes
    - name: Setup cachix
      uses: cachix/cachix-action@master
      with:
        name: linyinfeng
        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
    - name: Cache terraform
      uses: actions/cache@main
      with:
        path: terraform/.terraform/providers
        key: ${{ runner.os }}-terraform-providers-${{ hashFiles('terraform/.terraform.lock.hcl') }}
    - name: Terraform init
      run: |
        nix develop --command terraform-init
    - name: Terraform plan
      id: plan
      run: |
        set +e
        nix develop --command terraform-wrapper plan -out="$PWD/terraform/terraform.plan" -detailed-exitcode
        exit_code=$?
        set -e
        if [ "$exit_code" -eq 0 ]; then
          # success, empty diff
          echo "diff=false" >> $GITHUB_OUTPUT
        elif [ "$exit_code" -eq 2 ]; then
          # success, non-empty diff
          echo "diff=true" >> $GITHUB_OUTPUT
        else
          exit "$exit_code"
        fi
    - name: Encrypt plan
      if: steps.plan.outputs.diff == 'true'
      run: |
        nix develop --command bash -c "sops --encrypt terraform/terraform.plan > secrets/terraform.plan"
    - name: Upload plan
      if: steps.plan.outputs.diff == 'true'
      uses: actions/upload-artifact@main
      with:
        name: plan
        path: secrets/terraform.plan

  apply:
    runs-on: ubuntu-latest
    environment: infrastructure
    needs: [ plan ]
    if: |
      needs.plan.outputs.diff == 'true' &&
      github.ref == 'refs/heads/main'
    steps:
    - name: Checkout
      uses: actions/checkout@main
    - name: Install nix
      uses: cachix/install-nix-action@master
      with:
        install_url: https://github.com/numtide/nix-unstable-installer/releases/latest/download/install
        nix_path: nixpkgs=channel:nixos-unstable
        extra_nix_config: |
          experimental-features = nix-command flakes
    - name: Setup cachix
      uses: cachix/cachix-action@master
      with:
        name: linyinfeng
        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
    - name: Cache terraform
      uses: actions/cache@main
      with:
        path: terraform/.terraform/providers
        key: ${{ runner.os }}-terraform-providers-${{ hashFiles('terraform/.terraform.lock.hcl') }}
    - name: Terraform init
      run: |
        nix develop --command terraform-init
    - name: Download plan
      uses: actions/download-artifact@main
      with:
        name: plan
        path: secrets # secrets/terraform.plan
    - name: Decrypt plan
      run: |
        nix develop --command sops --decrypt secrets/terraform.plan > terraform/terraform.plan
    - name: Terraform apply
      run: |
        nix develop --command terraform-wrapper apply "$PWD/terraform/terraform.plan"
    - name: Terraform update outputs
      run: |
        nix develop --command terraform-update-outputs
    - name: Terraform extract secret and data
      run: |
        nix develop --command terraform-outputs-extract-secrets
        nix develop --command terraform-outputs-extract-data
    - name: Format
      run: |
        nix fmt
    - name: Commit and push
      run: |
        if [ -z "$(git status --porcelain)" ]; then
          echo "repository is clean, skip commit and push"
        else
          git config --global user.email "nano@linyinfeng.com"
          git config --global user.name "Nano"
          git add --all
          git commit --message "Terraform apply"
          git push
        fi