GitHub Actions

Diploi automatically generates a GitHub Actions workflow in your repository at .github/workflows/Build.yaml. This workflow builds Docker images for each component in your stack and pushes them to the Diploi container registry whenever you push code to any branch.

How it works

The workflow runs in two jobs:

Define Components — reads your diploi.yaml and outputs a build matrix describing each component and environment that needs an image.
Build — runs in parallel for each matrix entry, building and pushing the Docker image using the diploi/action-build action.

Default workflow

name: Build Components

on:
  push:
    branches:
      - '*'

jobs:
  define-components:
    name: Define Components
    runs-on: ubuntu-latest
    outputs:
      components: ${{ steps.diploi-meta.outputs.components }}
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      - id: diploi-meta
        name: Diploi meta
        uses: diploi/action-components@v1.8
  run-builds:
    name: Build ${{ matrix.name }} ${{ matrix.stage }}
    runs-on: ubuntu-24.04-arm
    needs: define-components
    strategy:
      fail-fast: false
      matrix:
        include: ${{ fromJSON(needs.define-components.outputs.components) }}
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      - name: Diploi build
        uses: diploi/action-build@v1.12
        with: ${{ matrix }}
        env:
          project: ${{ secrets.DIPLOI_REGISTRY_PROJECT }}
          registry: ${{ secrets.DIPLOI_REGISTRY_HOSTNAME }}
          username: ${{ secrets.DIPLOI_REGISTRY_USERNAME }}
          password: ${{ secrets.DIPLOI_REGISTRY_PASSWORD }}

Dockerfiles

The build action selects the Dockerfile to use based on the target environment:

Dockerfile.dev — used for the development environment, if it exists in the component’s folder.
Dockerfile — used for staging and production environments, and as a fallback for development if Dockerfile.dev is not present.

Both files are expected to be located inside the component’s folder (e.g. my-api/Dockerfile).

Registry secrets

The workflow expects four repository secrets to be configured. Diploi sets these automatically when you connect your repository.

Secret	Description
`DIPLOI_REGISTRY_HOSTNAME`	Hostname of the Diploi container registry
`DIPLOI_REGISTRY_PROJECT`	Project name within the registry
`DIPLOI_REGISTRY_USERNAME`	Registry login username
`DIPLOI_REGISTRY_PASSWORD`	Registry login password

Build arguments

Static ENV values defined in diploi.yaml under a component’s env block are forwarded to the Docker build as ARG variables. See Static Values for details on how to define them.

Exposing GitHub secrets to the build

If your Dockerfile needs access to sensitive values during the build — such as a private npm registry token or an API key for a build-time fetch — you can pass GitHub repository secrets to the build action using Docker BuildKit’s secret mounting.

Add a secrets key to the env block of the build step in your workflow:

      - name: Diploi build
        uses: diploi/action-build@v1.12
        with: ${{ matrix }}
        env:
          project: ${{ secrets.DIPLOI_REGISTRY_PROJECT }}
          registry: ${{ secrets.DIPLOI_REGISTRY_HOSTNAME }}
          username: ${{ secrets.DIPLOI_REGISTRY_USERNAME }}
          password: ${{ secrets.DIPLOI_REGISTRY_PASSWORD }}
          secrets: |
            NPM_TOKEN=${{ secrets.NPM_TOKEN }}

Then mount the secret in your Dockerfile using --mount=type=secret:

RUN --mount=type=secret,id=NPM_TOKEN \
    NPM_TOKEN=$(cat /run/secrets/NPM_TOKEN) npm install

Secrets mounted this way are never stored in the image layers, only available during the RUN step that mounts them.