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CruzJS

Azure Container Apps

Azure Container Apps is a managed container platform built on Kubernetes. It provides auto-scaling via KEDA, built-in ingress, and optional Dapr integration. CruzJS runs as a long-lived container with fire-and-forget waitUntil() support.

When to Use Container Apps

Section titled “When to Use Container Apps”
  • Sustained or high traffic
  • You need waitUntil() fire-and-forget behavior
  • You want managed identity (no passwords in config)
  • You need custom system dependencies or binaries
  • You want Dapr for service-to-service communication

For low traffic or event-driven workloads, consider Azure Functions instead.

Full Adapter Configuration

Section titled “Full Adapter Configuration”
import { AzureContainerAppsAdapter } from '@cruzjs/adapter-azure';


export default createCruzApp({
  schema,
  modules: [/* your modules */],
  adapter: new AzureContainerAppsAdapter({
    databaseUrl: process.env.DATABASE_URL,
    redisUrl: process.env.REDIS_URL,
    azureStorageConnectionString: process.env.AZURE_STORAGE_CONNECTION_STRING,
    azureStorageContainer: process.env.AZURE_STORAGE_CONTAINER,
    serviceBusConnectionString: process.env.SERVICE_BUS_CONNECTION_STRING,
    serviceBusQueueName: process.env.SERVICE_BUS_QUEUE_NAME,
  }),
  pages: () => import('virtual:react-router/server-build'),
});

waitUntil() Behavior

Section titled “waitUntil() Behavior”

Container Apps runs as container runtime type. The container stays alive between requests, so waitUntil() tasks execute as fire-and-forget — the response is sent immediately and background work continues.

Auto-Scaling with KEDA

Section titled “Auto-Scaling with KEDA”

Container Apps uses KEDA for event-driven scaling. The default HTTP scaler works for most CruzJS apps:

Terminal window
az containerapp create \
  --resource-group my-cruz-rg \
  --name my-cruz-app \
  --environment my-cruz-env \
  --image mycruzregistry.azurecr.io/my-cruz-app:latest \
  --target-port 3000 \
  --ingress external \
  --min-replicas 1 \
  --max-replicas 10 \
  --cpu 0.5 \
  --memory 1Gi \
  --scale-rule-name http-rule \
  --scale-rule-http-concurrency 50
SettingPurpose
--min-replicas 1Avoids cold starts by keeping one instance warm
--min-replicas 0Enables scale-to-zero for dev/staging
--scale-rule-http-concurrency 50Scale up when requests per instance exceed 50

Managed Identity

Section titled “Managed Identity”

Managed identity is the recommended way to connect to Azure services in production. It eliminates passwords and connection strings.

Terminal window
# Enable system-assigned identity
az containerapp identity assign \
  --resource-group my-cruz-rg \
  --name my-cruz-app \
  --system-assigned


# Grant access to PostgreSQL
az postgres flexible-server ad-admin create \
  --resource-group my-cruz-rg \
  --server-name my-cruz-db \
  --display-name my-cruz-app \
  --object-id $(az containerapp identity show --resource-group my-cruz-rg --name my-cruz-app --query principalId -o tsv)


# Grant access to Blob Storage
az role assignment create \
  --assignee $(az containerapp identity show --resource-group my-cruz-rg --name my-cruz-app --query principalId -o tsv) \
  --role "Storage Blob Data Contributor" \
  --scope /subscriptions/.../resourceGroups/my-cruz-rg/providers/Microsoft.Storage/storageAccounts/mycruzuploads

Dockerfile

Section titled “Dockerfile”
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npx cruz build


FROM node:20-alpine
WORKDIR /app
COPY --from=builder /app/build ./build
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./
ENV PORT=3000
EXPOSE 3000
CMD ["node", "build/server/index.js"]

Health Probes

Section titled “Health Probes”

Container Apps supports liveness, readiness, and startup probes:

Terminal window
az containerapp update \
  --resource-group my-cruz-rg \
  --name my-cruz-app \
  --set-env-vars="HEALTH_CHECK_PATH=/healthz" \
  --probe-type liveness \
  --probe-path /healthz \
  --probe-period 10 \
  --probe-timeout 5 \
  --probe-failure-threshold 3

CruzJS includes a built-in /healthz endpoint that returns 200 when the app is ready.

Dapr Integration (Optional)

Section titled “Dapr Integration (Optional)”

Dapr provides service invocation, pub/sub, and state management as sidecar capabilities:

Terminal window
az containerapp dapr enable \
  --resource-group my-cruz-rg \
  --name my-cruz-app \
  --dapr-app-id cruz-app \
  --dapr-app-port 3000 \
  --dapr-app-protocol http

Dapr is optional. CruzJS works without it using direct service connections.

Deployment

Section titled “Deployment”
Terminal window
# Create a Container Apps environment
az containerapp env create \
  --resource-group my-cruz-rg \
  --name my-cruz-env \
  --location eastus


# Build and push via Azure Container Registry
az acr build \
  --registry mycruzregistry \
  --image my-cruz-app:latest .


# Deploy
az containerapp create \
  --resource-group my-cruz-rg \
  --name my-cruz-app \
  --environment my-cruz-env \
  --image mycruzregistry.azurecr.io/my-cruz-app:latest \
  --registry-server mycruzregistry.azurecr.io \
  --target-port 3000 \
  --ingress external \
  --env-vars \
    DATABASE_URL="postgresql://cruzuser:pw@my-cruz-db.postgres.database.azure.com:5432/cruzdb?sslmode=require" \
    AUTH_SECRET=secretref:auth-secret \
    REDIS_URL="rediss://:key@my-cruz-cache.redis.cache.windows.net:6380" \
  --min-replicas 1 \
  --max-replicas 10 \
  --cpu 0.5 \
  --memory 1Gi

Next Steps

Section titled “Next Steps”