terraform-apply action

This is one of a suite of terraform related actions - find them at dflook/terraform-github-actions.

This action applies a terraform plan. The default behaviour is to apply the plan that has been added to a PR using the terraform-plan action.

If the plan is not found or has changed, then the apply action will fail. This is to ensure that the action only applies changes that have been reviewed by a human.

You can instead set auto_approve: true which will generate a plan and apply it immediately, without looking for a plan attached to a PR.

Demo

This a demo of the process for apply a terraform change using the dflook/terraform-plan and dflook/terraform-apply actions.

GitHub

To make best use of this action, require that the plan is always reviewed before merging the PR to approve. You can enforce this in github by going to the branch settings for the repo and enable protection for the master branch:

1. Enable 'Require pull request reviews before merging'
2. Check 'Dismiss stale pull request approvals when new commits are pushed'
3. Enable 'Require status checks to pass before merging', and select the job that runs the plan.
4. Enable 'Require branches to be up to date before merging'

Inputs

These input values must be the same as any terraform-plan for the same configuration. (unless auto_approve: true)

• path

  Path to the terraform root module to apply

  • Type: string
  • Optional
  • Default: The action workspace

• workspace

  Terraform workspace to run the apply in

  • Type: string
  • Optional
  • Default: default

• label

  A friendly name for the environment the terraform configuration is for. This will be used in the PR comment for easy identification.

  It must be the same as the label used in the corresponding terraform-plan command.

  • Type: string
  • Optional

• variables

  Variables to set for the terraform plan. This should be valid terraform syntax - like a variable definition file.

  with:
    variables: |
      image_id = "${{ secrets.AMI_ID }}"
      availability_zone_names = [
        "us-east-1a",
        "us-west-1c",
      ]

  Variables set here override any given in var_files. This can be used with remote backends such as Terraform Cloud/Enterprise, with variables set in the remote workspace having precedence.

  • Type: string
  • Optional

• var_file

  List of tfvars files to use, one per line. Paths should be relative to the GitHub Actions workspace

  with:
    var_file: |
      common.tfvars
      prod.tfvars

  This can be used with remote backends such as Terraform Cloud/Enterprise, with variables set in the remote workspace having precedence.

  • Type: string
  • Optional

• backend_config

  List of terraform backend config values, one per line.

  with:
    backend_config: token=${{ secrets.BACKEND_TOKEN }}

  • Type: string
  • Optional

• backend_config_file

  List of terraform backend config files to use, one per line. Paths should be relative to the GitHub Actions workspace

  with:
    backend_config_file: prod.backend.tfvars

  • Type: string
  • Optional

• replace

  List of resources to replace, one per line.

  Only available with terraform versions that support replace (v0.15.2 onwards).

  with:
    replace: |
      kubernetes_secret.tls_cert_public
      kubernetes_secret.tls_cert_private

  • Type: string
  • Optional

• target

  List of resources to apply, one per line. The apply operation will be limited to these resources and their dependencies.

  with:
    target: |
      kubernetes_secret.tls_cert_public
      kubernetes_secret.tls_cert_private

  • Type: string
  • Optional

• auto_approve

  When set to true, generated plans are always applied.

  The default is false, which requires plans to have been approved through a pull request.

  • Type: bool
  • Optional
  • Default: false

• parallelism

  Limit the number of concurrent operations

  • Type: number
  • Optional
  • Default: The terraform default (10)

• var

  ⚠️ Deprecated: Use the variables input instead.

  Comma separated list of terraform vars to set.

  This is deprecated due to the following limitations:

  • Only primitive types can be set with var - number, bool and string.
  • String values may not contain a comma.
  • Values set with var will be overridden by values contained in var_files
  • Does not work with the remote backend

  You can change from var to variables by putting each variable on a separate line and ensuring each string value is quoted.

  For example:

  with:
    var: instance_type=m5.xlarge,nat_type=instance

  Becomes:

  with:
    variables: |
      instance_type="m5.xlarge"
      nat_type="instance"

  • Type: string
  • Optional

Outputs

• json_plan_path

  This is the path to the generated plan in JSON Output Format The path is relative to the Actions workspace.

  This is not available when using terraform 0.11 or earlier. This also won't be set if the backend type is remote - Terraform does not support saving remote plans.

• text_plan_path

  This is the path to the generated plan in a human-readable format. The path is relative to the Actions workspace. This won't be set if auto_approve is true while using a remote backend.

• failure-reason

  When the job outcome is failure, this output may be set. The value may be one of:

  • apply-failed - The Terraform apply operation failed.
  • plan-changed - The approved plan is no longer accurate, so the apply will not be attempted.

  If the job fails for any other reason this will not be set. This can be used with the Actions expression syntax to conditionally run steps.

• Terraform Outputs

  An action output will be created for each output of the terraform configuration.

  For example, with the terraform config:

  output "service_hostname" {
    value = "example.com"
  }

  Running this action will produce a service_hostname output with the same value. See terraform-output for details.

Environment Variables

• GITHUB_TOKEN

  The GitHub authorization token to use to fetch an approved plan from a PR. The token provided by GitHub Actions can be used - it can be passed by using the ${{ secrets.GITHUB_TOKEN }} expression, e.g.

  env:
    GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

  The token provided by GitHub Actions will work with the default permissions. The minimum permissions are pull-requests: write. It will also likely need contents: read so the job can checkout the repo.

  You can also use a Personal Access Token which has the repo scope. This must belong to the same user as the token used by the terraform-plan action

  • Type: string
  • Optional

• TERRAFORM_CLOUD_TOKENS

  API tokens for terraform cloud hosts, of the form <host>=<token>. Multiple tokens may be specified, one per line. These tokens may be used with the remote backend and for fetching required modules from the registry.

  e.g for terraform cloud:

  env:
    TERRAFORM_CLOUD_TOKENS: app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}

  With Terraform Enterprise or other registries:

  env:
    TERRAFORM_CLOUD_TOKENS: |
      app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}
      terraform.example.com=${{ secrets.TF_REGISTRY_TOKEN }}

  • Type: string
  • Optional

• TERRAFORM_SSH_KEY

  A SSH private key that terraform will use to fetch git module sources.

  This should be in PEM format.

  For example:

  env:
    TERRAFORM_SSH_KEY: ${{ secrets.TERRAFORM_SSH_KEY }}

  • Type: string
  • Optional

• TERRAFORM_PRE_RUN

  A set of commands that will be ran prior to terraform init. This can be used to customise the environment before running terraform.

  The runtime environment for these actions is subject to change in minor version releases. If using this environment variable, specify the minor version of the action to use.

  The runtime image is currently based on debian:bullseye, with the command run using bash -xeo pipefail.

  For example:

  env:
    TERRAFORM_PRE_RUN: |
      # Install latest Azure CLI
      curl -skL https://aka.ms/InstallAzureCLIDeb | bash
      
      # Install postgres client
      apt-get install -y --no-install-recommends postgresql-client

  • Type: string
  • Optional

• TERRAFORM_HTTP_CREDENTIALS

  Credentials that will be used for fetching modules sources with git::http://, git::https://, http:// & https:// schemes.

  Credentials have the format <host>=<username>:<password>. Multiple credentials may be specified, one per line.

  Each credential is evaluated in order, and the first matching credentials are used.

  Credentials that are used by git (git::http://, git::https://) allow a path after the hostname. Paths are ignored by http:// & https:// schemes. For git module sources, a credential matches if each mentioned path segment is an exact match.

  For example:

  env:
    TERRAFORM_HTTP_CREDENTIALS: |
      example.com=dflook:${{ secrets.HTTPS_PASSWORD }}
      github.com/dflook/terraform-github-actions.git=dflook-actions:${{ secrets.ACTIONS_PAT }}
      github.com/dflook=dflook:${{ secrets.DFLOOK_PAT }}
      github.com=graham:${{ secrets.GITHUB_PAT }}  

  • Type: string
  • Optional

Example usage

Apply PR approved plans

This example workflow runs for every push to master. If the commit came from a PR that has been merged, applies the plan from the PR.

name: Apply

on:
  push:
    branches:
      - master

jobs:
  apply:
    runs-on: ubuntu-latest
    name: Apply approved plan
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: terraform apply
        uses: dflook/terraform-apply@v1
        with:
          path: my-terraform-config

Always apply changes

This example workflow runs for every push to master. Changes are planned and applied.

name: Apply

on:
  push:
    branches:
      - master

jobs:
  apply:
    runs-on: ubuntu-latest
    name: Apply terraform
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: terraform apply
        uses: dflook/terraform-apply@v1
        with:
          path: my-terraform-config
          auto_approve: true

Apply specific resources

This example workflow runs every morning and updates a TLS certificate if necessary.

name: Rotate certs

on:
  schedule:
    - cron:  "0 8 * * *"

jobs:
  apply:
    runs-on: ubuntu-latest
    name: Rotate certs
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: terraform apply
        uses: dflook/terraform-apply@v1
        with:
          path: my-terraform-config
          auto_approve: true
          target: |
            kubernetes_secret.tls_cert_public
            kubernetes_secret.tls_cert_private

Applying a plan using a comment

This workflow applies a plan on demand, triggered by someone commenting terraform apply on the PR. The plan is taken from an existing comment generated by the dflook/terraform-plan action.

name: Terraform Apply

on: [issue_comment]

jobs:
  apply:
    if: ${{ github.event.issue.pull_request && contains(github.event.comment.body, 'terraform apply') }}
    runs-on: ubuntu-latest
    name: Apply terraform plan
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: Checkout
        uses: actions/checkout@v2
        with:
          ref: refs/pull/${{ github.event.issue.number }}/merge

      - name: terraform apply
        uses: dflook/terraform-apply@v1
        with:
          path: my-terraform-config

This example retries the terraform apply operation if it fails.

name: Apply plan

on:
  push:
    branches:
      - master

jobs:
  plan:
    runs-on: ubuntu-latest
    name: Apply terraform plan
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: terraform apply
        uses: dflook/terraform-apply@v1
        continue-on-error: true
        id: first_try
        with:
          path: terraform

      - name: Retry failed apply
        uses: dflook/terraform-apply@v1
        if: ${{ steps.first_try.outputs.failure-reason == 'apply-failed' }}
        with:
          path: terraform
          auto_approve: true