Railway Preview Deploy Action

This GitHub Action automates the deployment of a preview environment for your Railway project whenever a pull request is opened in your repository. It works similarly to Vercel preview deployments. This allows you to easily review changes in a live environment before merging.

Features

• Deploys a new preview environment on every pull request.
• Supports custom environment variables for each deployment.
• Optionally reuses an existing preview environment for subsequent PRs.
• Optionally cleans up the environment when the PR is closed.
• Provides the deployed environment’s domain as an output for easy reference.

Inputs

Name	Description	Required	Default
railway_api_token	The Railway API token.	Yes
project_id	The Railway project ID. You can find it in the Railway dashboard under Settings > General.	Yes
environment_name	The name of the environment that serves as the base for the preview deployment.	Yes
environment_id	The environment ID that serves as the base for the preview deployment. If provided, environment_name will be ignored.	No
preview_environment_name	The name for the new preview environment. Use PR-specific naming, e.g., pr-<PR_NUMBER>-<SHORT_COMMIT_HASH>.	Yes
environment_variables	Environment variables to be set for the preview deployment, provided as a JSON object (e.g., {"KEY": "value"}).	No
api_service_name	The name of the API service for the PR environment, used to identify the deployed domain.	No
ignore_service_redeploy	A list of services to ignore when redeploying the PR environment. Useful for services that don't need redeployment on every PR.	No
branch_name	The branch name of the pull request used for the preview deployment.	Yes
reuse_preview_environment	Whether to reuse an existing preview environment if it has already been created.	No	true
cleanup	Whether to clean up the preview environment after the PR is closed.	No	false

Outputs

Name	Description
service_domain	The domain of the service that was deployed in the PR environment.

Usage

Here's an example of how you can use this action in your workflow file:

name: Deploy Preview Environment

on:
  pull_request:
    types: [opened, synchronize, reopened]

jobs:
  deploy-preview:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Railway Preview Deploy
        uses: ayungavis/[email protected]
        with:
          railway_api_token: ${{ secrets.RAILWAY_API_TOKEN }}
          project_id: ${{ secrets.RAILWAY_PROJECT_ID }}
          environment_name: 'staging'
          preview_environment_name: 'pr-${{ github.event.pull_request.number }}'
          environment_variables:
            '{"DATABASE_URL": "postgres://user:pass@host/db"}'
          branch_name: ${{ github.head_ref }}
          cleanup: 'true'

Inputs Breakdown:

• railway_api_token: The token to authenticate your Railway API requests.
• project_id: The ID of your Railway project.
• environment_name: The base environment that the preview deployment will be derived from (e.g., staging).
• preview_environment_name: A custom name for the preview environment, which you can dynamically set using the PR number and commit hash.
• environment_variables: Optional environment variables you can set, provided in JSON format.
• branch_name: The branch from the pull request.
• cleanup: Whether to clean up the preview environment after the PR is closed.

Example Workflow

The following example workflow deploys a preview environment on Railway for each pull request:

name: Railway Preview Deployment

on:
  pull_request:
    types: [opened, synchronize, reopened, closed]

permissions:
  contents: read
  pull-requests: write
  issues: write

concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    if: ${{ github.event.action != 'closed' }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Deploy to Railway
        uses: ayungavis/[email protected]
        with:
          railway_api_token: ${{ secrets.RAILWAY_API_TOKEN }}
          project_id: ${{ secrets.RAILWAY_PROJECT_ID }}
          environment_name: 'staging'
          preview_environment_name: 'pr-${{ github.event.pull_request.number }}'
          environment_variables: |
            {
              "DATABASE_URL": "postgres://username:password@hostname/db"
            }
          branch_name: ${{ github.head_ref }}

      - name: Post deployment info
        run:
          echo "Preview deployed at ${{ steps.deploy.outputs.service_domain }}"

      - name: Post or update deployment comment
        if: ${{ steps.test-action.outputs.service_domain != '' }}
        uses: actions/github-script@v6
        with:
          script: |
            const marker = '<!-- preview-comment -->'; // Unique marker to identify the comment
            const { data: commits } = await github.rest.pulls.listCommits({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.issue.number,
              per_page: 100 
            });
            const latestCommit = commits[commits.length - 1];
            const latestCommitSha = latestCommit.sha.substring(0, 7);
            const latestCommitAuthor = latestCommit.commit.author.name;


            const { data: comments } = await github.rest.issues.listComments({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo
            });

            const body = `
              ${marker}  <!-- This marker helps identify the comment for future updates -->
              🚀 **Deployment success!**

              - \`web\` deployed at [${{ steps.test-action.outputs.service_domain }}](https://${{ steps.test-action.outputs.service_domain }})

              ---

              *commit: ${latestCommitSha}*  
              *author: ${latestCommitAuthor}* 
            `;

            const existingComment = comments.find(comment => comment.body.includes(marker));

            if (existingComment) {
              await github.rest.issues.updateComment({
                comment_id: existingComment.id,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: body
              });
              core.info(`Updated comment ID: ${existingComment.id}`);
            } else {
              await github.rest.issues.createComment({
                issue_number: context.issue.number,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: body
              });
              core.info('Created a new comment');
            }

  cleanup:
    runs-on: ubuntu-latest
    if:
      ${{ github.event.pull_request.merged == true || github.event.action ==
      'closed' }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Cleanup Railway Environment
        uses: ayungavis/[email protected]
        with:
          railway_api_token: ${{ secrets.RAILWAY_API_TOKEN }}
          project_id: ${{ secrets.RAILWAY_PROJECT_ID }}
          environment_name: production
          preview_environment_name: 'pr-${{ github.event.pull_request.number }}'
          branch_name: ${{ github.head_ref }}
          cleanup: 'true'

License

This action is licensed under the MIT License.

This readme provides a clear description of the action, how to use it, and example workflow configurations to help users quickly set up and start using your GitHub Action.

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This PR is inspired by railway-pr-deploy but with some improvements and convert it to TypeScript.