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DSB's github actions for terraform

Collection of DSB custom GitHub actions and reusable workflows for terraform projects.

Actions

The actions are used by the CI/CD workflow(s) in .github/workflows. For documentation refer to the description section of each specific action as well as comments within their definition.

.
├── create-test-report    --> creates comment report with terraform test action results.
├── create-tf-vars-matrix --> creates common DSB terraform CI/CD variables
├── create-tftest-matrix  --> creates matrix for running terraform module test
├── export-env-vars       --> export environment variables for use in subsequent action steps
├── lint-with-tflint      --> run linting of terraform code with TFLint
├── setup-tflint          --> install TFLint and make available to subsequent action steps
├── terraform-plan        --> run terraform plan in directory
└── terraform-test        --> run terraform test in directory

Workflows

.
└── .github/workflows                           --> directory for reusable workflows
    ├── terraform-terraform-ci-cd-default.yml   --> default ci/cd workflow for DSB's 
    └── terraform-module-ci                     --> default ci workflow for module testing
    terraform projects

Workflow terraform-ci-cd-default

Default DSB CI/CD workflow for terraform projects that performs various operations depending on from what github event it was called and given input. Default behavior (when not modified by inputs):

  1. Install latest version of terraform
  2. Install latest version of TFLint
  3. Run terraform init
  4. Run terraform fmt -check
  5. Run terraform validate
  6. Perform linitng with TFLint
  7. If terraform init was successful, run terraform plan
  8. If called from pull_request event, add validation summary as comment on the PR
  9. If any of the steps init, format, validate, lint or plan failed, stop the workflow with a failure
  10. If called from either of events push or workflow_dispatch on the default branch of the calling repo and plan step was successful, run terraform apply. I.e. the default is to perform terraform apply when merging PRs.

What steps to execute and when can be modified using the input goals-yml, see description pf the input documented in the workflow.

Inputs

All inputs are documented in the workflow declaration.

The input environments-yml is required all others are optional, see description of each in the workflow declaration.

environments-yml

Specification of environments to run this terraform workflow and it's stages for. Minimum 1 environment must be specified.

Type: YAML list (as string) with specifications of environments to execute stages for.

Given that this is a list of environments (potentially with differing configuration), multiple entries in this list will cause parallel GitHub jobs to be spawned.

Only one field is required for each entry in this yaml list: environment - string. Using default behavior this is the name of a directory found within the /envs directory in the root of the calling repo. This directory is where all workflow steps are executed.

Example have the workflow execute steps within /envs/my-tf-environment of the calling repo:

environments-yml: |
  - environment: "my-tf-environment"

See more examples under example usage further down.

There are several optional fields for each entry in environments-yml, see description of each in the workflow declaration.

Variables and secrets

Normally you'll have the need to pass some variables or secrets to terraform in order to perform authentication or otherwise configure the terraform operations. This can be achieved by specifying them in extra-envs-yml and/or extra-envs-from-secrets-yml.

For global values, those to be passed for all terraform environments specified in environments-yml use the workflow inputs extra-envs-yml and extra-envs-from-secrets-yml.

For environment specific values specify the fields extra-envs-yml and extra-envs-from-secrets-yml for one or more environment defined in the environments-yml workflow input.

Example usage

Basic

Basic example of how to add terraform CI/CD to a github repo containing one environment under /envs/my-tf-environment. This would result in:

  • On PRs in the calling repo:
    • Perform: init, format, validate, lint and plan
    • Add comment on PR with results
  • When merging PRs in the calling repo:
    • First perform: init, format, validate, lint and plan
    • If successful, perform apply

The following would be saved as .github/workflows/ci-cd.yml in the calling repo.

For simplicity variables and secrets for authentication etc. have been left out.

name: "CI/CD"

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main
    types: [opened, synchronize, reopened]
  workflow_dispatch: # allows manual build

jobs:
  tf:
    uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-ci-cd-default.yml@v0
    secrets: inherit # pass all secrets, ok since we trust our own workflow
    permissions:
      contents: read # required for actions/checkout
      pull-requests: write # required for commenting on PRs
    with:
      environments-yml: |
        - environment: "my-tf-environment"

Multiple environments

Example of how to add terraform CI/CD with default operations to a github repo containing multiple environments not stored under the /envs directory.

# snip, 'name:' and 'on:' fields removed
jobs:
  tf:
    uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-ci-cd-default.yml@v0
    secrets: inherit # pass all secrets, ok since we trust our own workflow
    permissions:
      contents: read # required for actions/checkout
      pull-requests: write # required for commenting on PRs
    with:
      environments-yml: |
        - environment: "proj1"
          project-dir: "./terraform-projects/project-1"
        - environment: "proj2"
          project-dir: "./terraform-projects/project-2"

Advanced

Various examples of how to modify behavior.

# snip, 'name:' and 'on:' fields removed
jobs:

  # you can achieve passwordless auth to Azure
  tf-1:
    uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-ci-cd-default.yml@v0
    secrets: inherit # pass all secrets, ok since we trust our own workflow
    permissions:
      id-token: write # required for Azure password-less auth
      contents: read # required for actions/checkout
      pull-requests: write # required for commenting on PRs
    with:
      # these envs are 'global' and will be passed for all terraform environments specified below
      extra-envs-yml: |
        ARM_USE_OIDC: true
        ARM_USE_AZUREAD: true # ref. https://nedinthecloud.com/2022/06/08/using-oidc-authentication-with-the-azurerm-backend/
      # these values are not really secret but we load them from GitHub secrets either way
      # these envs are also 'global'
      extra-envs-from-secrets-yml: |
        ARM_CLIENT_ID: GITHUB_SECRETS_CLIENT_ID
        ARM_TENANT_ID: GITHUB_SECRETS_TENANT_ID
      # observe how each env can target different Azure subscriptions
      environments-yml: |
        - environment: "my-oidc-env-for-sub-1"
          extra-envs-from-secrets-yml:
            ARM_SUBSCRIPTION_ID: GITHUB_SECRETS_SUBSCRIPTION_1_ID
        - environment: "my-oidc-env-for-sub-2"
          extra-envs-from-secrets-yml:
            ARM_SUBSCRIPTION_ID: GITHUB_SECRETS_SUBSCRIPTION_2_ID

  # hardcoded versions and modify what steps are executed
  tf-2:
    uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-ci-cd-default.yml@v0
    secrets: inherit # pass all secrets, ok since we trust our own workflow
    permissions:
      contents: read # required for actions/checkout
      pull-requests: write # required for commenting on PRs
    with:
      terraform-version: "1.5.3"
      tflint-version: "v0.47.0"
      # First environment without apply step on PR merge, only validation
      # Second environment with all supported steps
      #   suitable ex. for integration tests etc. where the infra is always torn down
      environments-yml: |
        - environment: "only-validation"
          goals-yml: [init, format, validate, lint]
        - environment: "all-steps"
          goals-yml: [all, destroy-plan, destroy, apply-on-pr, destroy-on-pr]

Workflow terraform-module-ci

This GitHub Actions workflow is designed for Continuous Integration (CI) of Terraform modules.
Requirements:

  • The calling workflow must grant the following permissions:
   permissions:
     id-token: write       # Required for Azure password-less authentication
     contents: read        # Required for actions/checkout
     pull-requests: write  # Required for commenting on PRs

Inputs:

  • terraform-version: The version of Terraform to use for the tests (required).
  • tflint-version: The version of tflint (required)

Secrets

There are two possibilities to pass secrets to this action. Either use of secrets: inherit or through environment variables:

  • ARM_TENANT_ID: Azure Tenant ID (from REPO secrets)
  • ARM_SUBSCRIPTION_ID: Azure Subscription ID (from REPO secrets)
  • ARM_CLIENT_ID: Azure Service Principal Client ID (from REPO secrets)

Env variables below are required.

  • ARM_USE_OIDC: Enable OIDC for Azure authentication
  • ARM_USE_AZUREAD: Enable Azure AD for authentication
  • TF_IN_AUTOMATION: Set to true to indicate Terraform is running in automation

Jobs:

  1. create-matrix:

    • Steps:
      • Clean workspace
      • Checkout working branch
      • Create job matrix that contains list of test files to run ( for parallelism ).
      • Setup Terraform
      • install tfflint
      • Setup terraform provider plugin cache
      • Terraform Init
      • Terraform Format
      • Terraform Validate
      • tflint
      • Create init report
      • Add validation summary as pull request comment
      • Validate outcomes of init, validate, format and tflint steps

  2. terraform-module-ci:

    • Steps:
      • Checkout working branch
      • Setup Terraform
      • Terraform Test
      • Create test report
      • Add validation summary as pull request comment
      • Validate outcomes of init and test

  3. conclusion:

    • Steps:
      • Exit with status 1 if any of the previous jobs failed or were cancelled

Example:

name: "tf"

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main
    types: [opened, synchronize, reopened]
  workflow_dispatch: # allows manual build

jobs:
  tf:
    uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-module-ci.yaml@tf-test
    secrets: inherit
    permissions:
        contents: read  # required for checkout action. 
        id-token: write # required for Azre passwodless login
        pull-requests: write # required for commenting on PR
    with:
      terraform-version: "1.9.x"
      tflint-version: "v0.53.0"

Maintenance

Development

  1. Replace version-tag of all dsb-actions in this repo with a temporary tag, ex. @v2 becomes @my-feature.

    Replace regex pattern for vscode:

    • Find: (^\s*)((- ){0,1}uses: dsb-norge/github-actions-terraform/.*@)v2
    • Replace: $1# TODO revert to @v2\n$1$2my-feature

  2. Make your changes and commit your changes on a branch, for example my-feature-branch.

  3. Tag latest commit on you branch:

    git tag -f -a 'my-feature'
git push -f origin 'refs/tags/my-feature'

  4. To try out your changes, in the calling repo change the calling workflow to call using your branch name. Ex. with a dev branch named my-feature-branch:

     jobs:
     ci-cd:
       # TODO revert to '@v2'
       uses: dsb-norge/github-actions-terraform/.github/workflows/terraform-ci-cd-default.yml@my-feature-branch

  5. Test your changes from the calling repo. Make changes and remember to always move your tag my-feature to the latest commit.

  6. When ready remove your temporary tag:

    git tag --delete 'my-feature'
git push --delete origin 'my-feature'

    and revert from using the temporary tag to the version-tag for your release in actions, i.e. @my-feature becomes @v2 or @v3 or whatever.

    Replace regex pattern for vscode:

    • Find: (^\s*# TODO revert to @v2\n)(^\s*)((- )?uses: dsb-norge/github-actions-terraform/.*@)my-feature
    • Replace: $2$3v2

  7. Create PR and merge to main.

Release

After merge to main use tags to release.

Minor release

Ex. for smaller backwards compatible changes. Add a new minor version tag ex v1.0 with a description of the changes and amend the description to the major version tag.

Example for release v1.1:

git checkout origin/main
git pull origin main
git tag -a 'v1.1'
# you are prompted for the tag annotation (change description)
git tag -f -a 'v1'
# you are prompted for the tag annotation, amend the change description
git push -f origin 'refs/tags/v1.1'
git push -f origin 'refs/tags/v1'

Note: If you are having problems pulling main after a release, try to force fetch the tags: git fetch --tags -f.

Major release

Same as minor release except that the major version tag is a new one. I.e. we do not need to force tag/push.

Example for release v1:

git checkout origin/main
git pull origin main
git tag -a 'v1.0'
# you are prompted for the tag annotation (change description)
git tag -a 'v1'
# you are prompted for the tag annotation
git push -f origin 'refs/tags/v1.0'
git push -f origin 'refs/tags/v1'

Note: If you are having problems pulling main after a release, try to force fetch the tags: git fetch --tags -f.