CDKTF Diff

Execute cdktf diff, parse STDOUT/STDERR output, and return outputs based on the outcomes.

Usage

jobs:
  run_diffs:
    name: Run diffs
    strategy:
      fail-fast: false
      matrix: 
        name: ["project-stack", "qa-stack", "prod-stack"]
    runs-on: ubuntu-latest
    steps:
      - name: "${{ matrix.name }}: Diff for my-feature-branch"
        uses: snapsheet/cdktf-diff@TEST_SRE-2249-cdktf-diff-standalone-action
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          job_name: Run diffs (${{ matrix.name }}) # Needs to match the name of the job as it will show in the run, including interpolations.
          output_filename: outputs.json
          ref: my-feature-branch
          stack: ${{ matrix.name }}
          terraform_version: ${{ inputs.terraform_version }}
          working_directory: ./cdktf

Inputs

Input	Required?	Default	Description
github_token	true		The GitHub token used to create an authenticated client. For most cases, set this to ${{ secrets.GITHUB_TOKEN }}
job_name	true		jobs.<job-id>.name of this workflow job. This is needed to get the job ID via query. This needs to match the name of the job as it will show in the run, including interpolations.
output_filename	true	"./"	Working directory path that contains your cdktf code.
ref	true		The ref (branch or SHA) to use with the diff.
stack	true		Full name of the CDKTF stack to diff.
stub_output_file	false		When present, no Terraform will execute. The output of this action will be substituted with the output contained in this file. This is useful for cases when you want to test but don't have authentication set up.
terraform_version	false	1.8.0	The version of Terraform to use
working_directory	false	"./"	Working directory path that contains your cdktf code.

Outputs

Output	Description
html_url	Direct link to this job, which shows the full execution output.
job_id	ID of this job.
result_code	Similar to -detailed-exitcode behavior for Terraform, not yet supported by CDKTF. 0 = Succeeded with empty diff (no changes), 1 = Error, 2 = Succeeded with non-empty diff (changes present)
stack	Full name of the CDKTF stack used for the diff.
summary	Single string of output to summarize the results (ie, No changes. Your infrastructure matches the configuration.)

Testing

You can test how this process parses output by using inputs.stub_output_file. When present, Terraform processes will not be ran, and instead the given file will be used to simulate the output of running cdktf diff. You can generate an example file by running the following:

CI=1 cdktf diff > my-example-file.txt

Assuming this file is in the root path of your repository directory, you reference it in the config:

jobs:
  run_diffs:
    name: Run diffs
    strategy:
      fail-fast: false
      matrix: 
        name: ["project-stack", "qa-stack", "prod-stack"]
    runs-on: ubuntu-latest
    steps:
      - name: "${{ matrix.name }}: Diff for my-feature-branch"
        uses: snapsheet/cdktf-diff@TEST_SRE-2249-cdktf-diff-standalone-action
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          job_name: Run diffs (${{ matrix.name }})
          output_filename: outputs.json
          ref: my-feature-branch
          stack: ${{ matrix.name }}
          stub_output_file: my-example-file.txt # <-- LIKE THIS
          terraform_version: ${{ inputs.terraform_version }}
          working_directory: ./cdktf