Github Actions - Monorepo deploy workflow

deploy.yml

# Deploy frontend after successful backend deployment in sequence
# If frontend changed, deploy only frontend
# If backend changed, deploy only backend
# If frontend and backend, deploy frontend after backend

name: "Deploy services"
on:
  push:
    branches: ["main"]
jobs:
  # JOB to run change detection
  changes:
    name: "Filter changed files"
    runs-on: ubuntu-latest
    # Set job outputs to values from filter step
    outputs:
      backend: ${{ steps.filter.outputs.backend }}
      frontend: ${{ steps.filter.outputs.frontend }}
    steps:
      - uses: actions/checkout@v2
      # For pull requests it's not necessary to checkout the code
      - uses: dorny/paths-filter@v2
        id: filter
        with:
          filters: |
            backend:
              - 'applications/backend/**'
            frontend:
              - 'applications/frontend/**'

  # trigger backend if backend is changed
  backend:
    needs: changes
    if: needs.changes.outputs.backend == 'true'
    uses: organization/repository/.github/workflows/deploy-backend.yml@main

  # trigger frontend if only frontend is changed
  frontend:
    needs: changes
    if: needs.changes.outputs.frontend == 'true' && needs.changes.outputs.backend == 'false'
    uses: organization/repository/.github/workflows/deploy-frontend.yml@main

  # trigger frontend after backend if both are changed
  frontend-after-backend:
    needs: backend
    if: needs.changes.outputs.frontend == 'true' && needs.changes.outputs.backend == 'true'
    uses: organization/repository/.github/workflows/deploy-frontend.yml@main