SKILL.md
CI/CD
Core Principles
- Pipeline as code — YAML pipelines committed to the repo. No click-ops in the UI.
- Fast feedback — Build and test on every push. Cache NuGet packages. Fail fast.
- Build once, deploy many — Build the artifact once, promote it through environments (dev → staging → production).
- 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
```yaml
# .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
Azure DevOps — Build + Test
Same restore → build → format → test flow as GitHub Actions. Key differences:
# azure-pipelines.yml
trigger:
branches:
include: [main]
paths:
exclude: ['*.md', docs/]
pool:
vmImage: 'ubuntu-latest' # vs runs-on: ubuntu-latest
variables:
dotnetVersion: '10.0.x'
# Key task differences from GitHub Actions:
# Setup .NET: task: UseDotNet@2 (inputs: version: $(dotnetVersion))
# Test results: task: PublishTestResults@2 (testResultsFormat: VSTest)
# Steps use `script:` + `displayName:` instead of `- name:` + `run:`
# Services (e.g., Postgres) require a separate Docker task or pipeline service connection
NuGet Package Publishing
# Part of GitHub Actions workflow
- name: Pack
run: dotnet pack src/MyLibrary -c Release -o ./nupkg --no-build
- name: Push to NuGet
run: dotnet nuget push ./nupkg/*.nupkg --api-key ${{ secrets.NUGET_API_KEY }} --source https://api.nuget.org/v3/index.json
Anti-patterns
Don't Build Different Artifacts per Environment
# BAD — building separately for each environment
- script: dotnet publish -c Debug # for dev
- script: dotnet publish -c Release # for prod
# GOOD — build once, deploy everywhere
- script: dotnet publish -c Release -o ./publish
# Then deploy the same ./publish artifact to dev, staging, prod
Don't Skip Format Checks in CI
# BAD — no format enforcement
steps:
- run: dotnet build
- run: dotnet test
# GOOD — format check catches style issues early
steps:
- run: dotnet build
- run: dotnet format --verify-no-changes
- run: dotnet test
Don't Hardcode Secrets in Pipelines
# BAD — secret in pipeline YAML
env:
DB_PASSWORD: "my-secret-password"
# GOOD — use pipeline secrets
env:
DB_PASSWORD: ${{ secrets.DB_PASSWORD }}
Decision Guide
| Scenario | Recommendation |
|---|---|
| Open source project | GitHub Actions |
| Enterprise with Azure | Azure DevOps Pipelines |
| Docker deployment | Multi-stage build in CI, push to container registry |
| NuGet library | Build → Test → Pack → Push on tag |
| Database migrations | Run in CI test stage, script for production |
| Environment promotion | Same artifact, different configuration |