ci-cd

CI/CD

Core Principles

1. Pipeline as code — YAML pipelines committed to the repo. No click-ops in the UI.
2. Fast feedback — Build and test on every push. Cache NuGet packages. Fail fast.
3. Build once, deploy many — Build the artifact once, promote it through environments (dev → staging → production).
4. Never skip tests — Tests gate the pipeline. No deployment without passing tests.

Patterns

GitHub Actions — Build + Test

# .github/workflows/ci.yml
name: CI

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

env:
  DOTNET_VERSION: '10.0.x'
  DOTNET_NOLOGO: true
  DOTNET_CLI_TELEMETRY_OPTOUT: true

jobs:
  build-and-test:
    runs-on: ubuntu-latest

    services:
      postgres:
        image: postgres:18
        env:
          POSTGRES_DB: testdb
          POSTGRES_USER: postgres
          POSTGRES_PASSWORD: postgres
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

    steps:
      - uses: actions/checkout@v5

      - name: Setup .NET
        uses: actions/setup-dotnet@v5
        with:
          dotnet-version: ${{ env.DOTNET_VERSION }}

      - name: Restore
        run: dotnet restore

      - name: Build
        run: dotnet build --no-restore --configuration Release

      - name: Format check
        run: dotnet format --verify-no-changes --no-restore

      - name: Test
        run: dotnet test --no-build --configuration Release --logger trx --results-directory TestResults
        env:
          ConnectionStrings__Default: "Host=localhost;Database=testdb;Username=postgres;Password=postgres"

      - name: Publish test results
        uses: actions/upload-artifact@v5
        if: always()
        with:
          name: test-results
          path: TestResults/*.trx

GitHub Actions — Build + Publish Docker Image

# .github/workflows/publish.yml
name: Publish

on:
  push:
    tags: ['v*']

jobs:
  publish:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - uses: actions/checkout@v5

      - name: Login to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract version from tag
        id: version
        run: echo "VERSION=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          push: true
          tags: |
            ghcr.io/${{ github.repository }}:${{ steps.version.outputs.VERSION }}
            ghcr.io/${{ github.repository }}:latest