action.yml

name: Terraform Plan Custom Action

description: Performs a Terraform plan and returns the output

inputs:
  tfDir:
    description: The directory where the Terraform templates are located
    required: false
    default: ""
  tfArgs:
    description: Extra arguments to pass to terraform
    required: false
    default: ""
  tfWorkspace:
    description: The Terraform workspace to select
    required: false
    default: "default"
  gitUser:
    description: The Git user used to clone repositories
    required: true
  gitToken:
    description: The Git user token used to clone repositories
    required: true
  commentPrNumber:
    description: Pull Request ID to add the TF Plan comment
    required: false
  commentTitle:
    description: Main title for TF Plan comment on Pull Request
    required: false
    default: Terraform Plan Results
  commentSubTitle:
    description: Sub title for TF Plan comment on Pull Request
    required: false
    default: Terraform Plan

outputs:
  tfplan:
    description: The Terraform plan output
    value: ${{ steps.plan.outputs.plan_output }}
  message:
    description: Friendly message that shows if there are changes to review
    value: ${{ steps.plan.outputs.plan_msg }}
  result:
    description: The return code of the plan. 0 = no changes, 1 = error, 2 = changes
    value: ${{ steps.plan.outputs.plan_result }}

runs:
  using: "composite"
  steps:
    - name: Terraform formatting
      shell: bash
      working-directory: ${{inputs.tfDir}}
      run: |
        terraform fmt -check -recursive -diff

    - name: Setup Git
      shell: bash
      env:
        GIT_USER: ${{inputs.gitUser}}
        GIT_TOKEN: ${{inputs.gitToken}}     
      run: |
        git config --global credential.helper store
        echo "https://$GIT_USER:GIT_TOKEN@github.com" >> ~/.git-credentials
    
    - name: Terraform Init
      shell: bash
      working-directory: ${{inputs.tfDir}}
      run: | 
       terraform init -input=false
       terraform workspace select ${{ inputs.tfWorkspace }} || terraform workspace new ${{ inputs.tfWorkspace }}

    - name: Terraform Plan
      shell: bash
      id: plan
      working-directory: ${{ inputs.tfDir }}
      run: |
        PLAN_OUTPUT="$(terraform plan -no-color -detailed-exitcode -out=tfplan ${{ inputs.tfArgs }})" || PLAN_RESULT=$?
        echo "plan_result=$PLAN_RESULT" >> $GITHUB_OUTPUT

        if [ "${#PLAN_OUTPUT}" -gt 131071 ]; then
          PLAN_OUTPUT="The plan output was too big to comment. Please view the actions output for the plan results.";
        fi
        
        # echo "plan_output=$PLAN_OUTPUT" >> $GITHUB_OUTPUT

        EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
        echo "plan_output<<$EOF" >> $GITHUB_OUTPUT
        echo "$PLAN_OUTPUT" >> $GITHUB_OUTPUT
        echo "$EOF" >> $GITHUB_OUTPUT
        

        case $PLAN_RESULT in
          1)
            exit 1
            ;;
          2)
            MSG="Changes to review! :warning:"
            ;;
          *)
            MSG="No changes :white_check_mark:"
            ;;
        esac
        echo "plan_msg=$MSG" >> $GITHUB_OUTPUT

        terraform show -json tfplan > tfplan.json
        terraform show tfplan

    - name: Add TF Plan comment to PR
      if: ${{ inputs.commentPrNumber != '' && steps.plan.outcome == 'success'}}
      shell: bash
      working-directory: ${{ inputs.tfDir }}
      run: |
        echo "## ${{ inputs.commentTitle }} &#128195;" > comment.txt
        echo "### ${{ inputs.commentSubTitle }}" >> comment.txt
        echo "${{ steps.plan.outputs.plan_msg }}" >> comment.txt
        echo "<details><summary>Show Plan</summary>" >> comment.txt
        echo "" >> comment.txt
        echo "\`\`\`terraform" >> comment.txt
        echo "${{ steps.plan.outputs.plan_output }}" >> comment.txt
        echo "\`\`\`" >> comment.txt
        echo "</details>" >> comment.txt

        PR_PAYLOAD="$(echo '{}' | jq --arg body "$(cat comment.txt)" '.body = $body')"

        curl -sS \
          -X POST \
          -H "Accept: application/vnd.github+json" \
          -H "Authorization: Bearer ${{ github.token }}"\
          -H "X-GitHub-Api-Version: 2022-11-28" \
          -L "https://api.github.com/repos/${{ github.repository }}/issues/${{ inputs.commentPrNumber }}/comments" \
          --data "$PR_PAYLOAD"
          
    - name: Cleanup
      shell: bash
      run: rm ~/.git-credentials

branding:
  icon: 'award'
  color: 'green'