Design and implement deployments

# 1 · Deploy to the staging slot (green) — production traffic unaffected
az webapp deploy --resource-group myRG --name myApp --slot staging \
  --src-path ./package.zip --type zip

# 2 · Warm up and smoke-test the staging slot
curl -fsS https://myapp-staging.azurewebsites.net/health

# 3 · Swap — Azure warms the target first, so this is near-zero downtime
az webapp deployment slot swap --resource-group myRG --name myApp \
  --slot staging --target-slot production

# 4 · Rollback = swap again (the old version is now sitting in staging)
az webapp deployment slot swap --resource-group myRG --name myApp \
  --slot staging --target-slot production

- deployment: CanaryDeploy
  environment: production
  strategy:
    canary:
      increments: [10, 25, 50]      # then the remainder
      preDeploy:
        steps: [ { script: ./prepare.sh } ]
      deploy:
        steps: [ { script: ./deploy.sh --weight $(strategy.increment) } ]
      routeTraffic:
        steps: [ { script: ./shift-traffic.sh $(strategy.increment) } ]
      postRouteTraffic:
        steps: [ { script: ./check-health.sh } ]   # fail here → on: failure
      on:
        failure:
          steps: [ { script: ./rollback.sh } ]

- deployment: RollingDeploy
  environment: vm-farm
  strategy:
    rolling:
      maxParallel: 25%          # update a quarter of targets at a time
      preDeploy:
        steps: [ { script: ./drain-from-load-balancer.sh } ]
      deploy:
        steps: [ { script: ./install.sh } ]
      routeTraffic:
        steps: [ { script: ./add-back-to-load-balancer.sh } ]
      postRouteTraffic:
        steps: [ { script: ./verify.sh } ]
      on:
        failure:
          steps: [ { script: ./rollback.sh } ]

// Program.cs — connect with a managed identity, no connection string
builder.Configuration.AddAzureAppConfiguration(options =>
{
    options.Connect(new Uri(builder.Configuration["AppConfig:Endpoint"]!),
                    new DefaultAzureCredential())
           .UseFeatureFlags(ff => ff.CacheExpirationInterval = TimeSpan.FromMinutes(5));
});
builder.Services.AddAzureAppConfiguration();
builder.Services.AddFeatureManagement().AddFeatureFilter<TargetingFilter>();

// Usage
public async Task<IActionResult> Index()
{
    if (await _featureManager.IsEnabledAsync("NewDashboard"))
        return View("NewDashboard");
    return View("Dashboard");
}

stages:
  - stage: Infrastructure
    jobs: [ { job: Bicep, steps: [ { script: az deployment group create ... } ] } ]

  - stage: Database
    dependsOn: Infrastructure
    condition: succeeded('Infrastructure')
    jobs: [ { job: Migrate, steps: [ { script: ./migrate.sh } ] } ]

  - stage: Api
    dependsOn: Database                # API depends on the new schema
    jobs: [ { deployment: DeployApi, environment: prod, strategy: { runOnce: { deploy: { steps: [ { script: ./deploy-api.sh } ] } } } } ]

  - stage: Web
    dependsOn: Api                     # front end depends on the API
    jobs: [ { deployment: DeployWeb, environment: prod, strategy: { runOnce: { deploy: { steps: [ { script: ./deploy-web.sh } ] } } } } ]

trigger:
  branches: { include: ['hotfix/*'] }

steps:
  - script: dotnet test --filter "Category=Smoke|Category=Regression"
  - task: AzureWebApp@1
    condition: succeeded()
    inputs:
      appName: myApp
      deployToSlotOrASE: true
      slotName: staging          # then swap — rollback stays instant
      package: '$(Build.ArtifactStagingDirectory)/**/*.zip'

# State-based: DACPAC publish
- task: SqlAzureDacpacDeployment@1
  inputs:
    azureSubscription: 'MyServiceConnection'
    AuthenticationType: 'servicePrincipal'
    ServerName: 'myserver.database.windows.net'
    DatabaseName: 'mydb'
    deployType: 'DacpacTask'
    DeploymentAction: 'Publish'
    DacpacFile: '$(Pipeline.Workspace)/drop/MyApp.dacpac'
    # Leave BlockOnPossibleDataLoss at its default (true) in production!
    AdditionalArguments: '/p:BlockOnPossibleDataLoss=true'

# Migration-based: generate an idempotent script, review it, then apply
- script: |
    dotnet ef migrations script --idempotent \
      --project src/MyApp.Data --startup-project src/MyApp.Api \
      --output $(Build.ArtifactStagingDirectory)/migrate.sql
  displayName: Generate migration script