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07 - Extending Triggers (Dedicated)

Add queue, timer, and blob triggers with the Node.js v4 APIs and deploy to Dedicated.

Prerequisites

  • You completed 06 - CI/CD.
  • Your function app $APP_NAME is deployed and running on the Dedicated plan.

What You'll Build

  • Extend your app with timer, queue, and blob triggers using the Node.js v4 programming model.
  • Deploy all triggers to Dedicated and verify they index correctly.
  • Understand Always On requirements for non-HTTP triggers on Dedicated plans.

Infrastructure Context

Plan: Dedicated (B1) | Triggers: HTTP + Timer + Queue + Blob + EventHub | Always On: ✅ (required)

Dedicated plans require Always On for non-HTTP triggers. Without it, the app may idle after 20 minutes and miss timer/queue/blob events. The reference app includes 20 functions across all trigger types.

flowchart TD
    TIMER["⏰ Timer Trigger\nscheduledCleanup\ntimerLab"] -->|CRON schedule| FA[Function App\nDedicated B1]
    QUEUE["📨 Queue Trigger\nqueueProcessor"] -->|Queue message| FA
    BLOB["📦 Blob Trigger\nblobProcessor"] -->|Blob event| FA
    HTTP["🌐 HTTP Triggers\nhelloHttp, health\ninfo, logLevels"] -->|HTTPS| FA
    EH["📡 EventHub Trigger\neventhubLagProcessor"] -->|Event stream| FA

    FA --> ALWAYS["Always On ✅\nKeeps app warm\nfor non-HTTP triggers"]

    style FA fill:#ff8c00,color:#fff
    style ALWAYS fill:#E8F5E9,stroke:#4CAF50
    style TIMER fill:#E3F2FD
    style QUEUE fill:#E3F2FD
    style BLOB fill:#E3F2FD
    style HTTP fill:#E3F2FD
    style EH fill:#E3F2FD

Steps

  1. Add timer trigger.

    The reference app includes src/functions/scheduledCleanup.js:

    const { app } = require('@azure/functions');

app.timer('scheduledCleanup', {
    schedule: '0 0 2 * * *',
    handler: async (_timer, context) => {
        context.log('Nightly cleanup job fired');
    }
});

    Always On required for timers

    On Dedicated plans, timer triggers only fire if Always On is enabled. Without it, the app may idle and miss scheduled executions.

  2. Add queue trigger.

    The reference app includes src/functions/queueProcessor.js:

    const { app } = require('@azure/functions');

app.storageQueue('queueProcessor', {
    queueName: 'incoming-orders',
    connection: 'QueueStorage',
    handler: async (queueItem, context) => {
        context.log(`Order received: ${JSON.stringify(queueItem)}`);
    }
});

    Queue connection setting

    The connection property (QueueStorage) must match an app setting containing the storage connection string. Set it during deployment:

    az functionapp config appsettings set \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --settings "QueueStorage=$(az storage account show-connection-string --name $STORAGE_NAME --resource-group $RG --query connectionString --output tsv)"

  3. Add blob trigger.

    The reference app includes src/functions/blobProcessor.js:

    const { app } = require('@azure/functions');

app.storageBlob('blobProcessor', {
    path: 'uploads/{name}',
    connection: 'AzureWebJobsStorage',
    source: 'EventGrid',
    handler: async (blob, context) => {
        context.log(`Processing blob: ${context.triggerMetadata.name}, size: ${blob.length} bytes`);
    }
});

  4. Deploy and verify trigger indexing.

    cd apps/nodejs
func azure functionapp publish "$APP_NAME"

    Wait 30–60 seconds for indexing, then verify:

    az functionapp function list \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --output table

    Expected output (all 20 functions):

    Name                                          Language
--------------------------------------------  ----------
func-ndded-04100022/blobProcessor             node
func-ndded-04100022/checkReplayStatus         node
func-ndded-04100022/dnsResolve                node
func-ndded-04100022/eventhubLagProcessor      node
func-ndded-04100022/externalDependency        node
func-ndded-04100022/health                    node
func-ndded-04100022/helloHttp                 node
func-ndded-04100022/identityProbe             node
func-ndded-04100022/info                      node
func-ndded-04100022/logLevels                 node
func-ndded-04100022/queueProcessor            node
func-ndded-04100022/replayLabActivity         node
func-ndded-04100022/replayStormOrchestrator   node
func-ndded-04100022/scheduledCleanup          node
func-ndded-04100022/slowResponse              node
func-ndded-04100022/startReplayLab            node
func-ndded-04100022/storageProbe              node
func-ndded-04100022/testError                 node
func-ndded-04100022/timerLab                  node
func-ndded-04100022/unhandledError            node

  5. Test HTTP endpoints after deployment.

    curl --request GET "https://$APP_NAME.azurewebsites.net/api/health"

    Expected output:

    {"status":"healthy","timestamp":"2026-04-09T16:05:04.222Z","version":"1.0.0"}

    curl --request GET "https://$APP_NAME.azurewebsites.net/api/hello/Triggers"

    Expected output:

    {"message":"Hello, Triggers"}

  6. Review Dedicated trigger-specific notes.

    • Always On: Required for timer, queue, blob, and EventHub triggers. Without it, Dedicated apps idle after ~20 minutes.
    • EventHub placeholder: Set EventHubConnection__fullyQualifiedNamespace=placeholder.servicebus.windows.net to allow indexing without a real EventHub.
    • Queue connection: QueueStorage app setting must contain a valid storage connection string for queueProcessor to index.
    • No auto-scale: Dedicated plans do not scale automatically based on queue depth or event backlog. For auto-scaling workloads, use Premium or Consumption.

Verification

The host output confirms all triggers are indexed and available. Verify:

  • az functionapp function list shows all 20 functions with language node
  • HTTP endpoints return expected responses
  • Timer triggers (scheduledCleanup, timerLab) are listed — they will fire on schedule only if Always On is enabled

See Also

Sources