Azure Event Grid binding spec

Detailed documentation on the Azure Event Grid binding component

Component format

To setup an Azure Event Grid binding create a component of type bindings.azure.eventgrid. See this guide on how to create and apply a binding configuration.

See this for the documentation for Azure Event Grid.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <name>
spec:
  type: bindings.azure.eventgrid
  version: v1
  metadata:
  # Required Output Binding Metadata
  - name: accessKey
    value: "[AccessKey]"
  - name: topicEndpoint
    value: "[TopicEndpoint]"
  # Required Input Binding Metadata
  - name: azureTenantId
    value: "[AzureTenantId]"
  - name: azureSubscriptionId
    value: "[AzureSubscriptionId]"
  - name: azureClientId
    value: "[ClientId]"
  - name: azureClientSecret
    value: "[ClientSecret]"
  - name: subscriberEndpoint
    value: "[SubscriberEndpoint]"
  - name: handshakePort
    # Make sure to pass this as a string, with quotes around the value
    value: "[HandshakePort]"
  - name: scope
    value: "[Scope]"
  # Optional Input Binding Metadata
  - name: eventSubscriptionName
    value: "[EventSubscriptionName]"

Warning

The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described here.

Spec metadata fields

Scope

Scope is the identifier of the resource to which the event subscription needs to be created or updated. The scope can be a subscription, a resource group, a top-level resource belonging to a resource provider namespace, or an Event Grid topic. For example:

• /subscriptions/{subscriptionId}/ for a subscription
• /subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName} for a resource group
• /subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/{resourceProviderNamespace}/{resourceType}/{resourceName} for a resource
• /subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.EventGrid/topics/{topicName} for an Event Grid topic

Values in braces {} should be replaced with actual values.

Binding support

This component supports both input and output binding interfaces.

This component supports output binding with the following operations:

• create: publishes a message on the Event Grid topic

Azure AD credentials

The Azure Event Grid binding requires an Azure AD application and service principal for two reasons:

• Creating an event subscription when Dapr is started (and updating it if the Dapr configuration changes)
• Authenticating messages delivered by Event Hubs to your application.

Requirements:

• The Azure CLI installed.
• PowerShell 7 installed.
• Az module for PowerShell for PowerShell installed:
  Install-Module Az -Scope CurrentUser -Repository PSGallery -Force
• Microsoft.Graph module for PowerShell for PowerShell installed:
  Install-Module Microsoft.Graph -Scope CurrentUser -Repository PSGallery -Force

For the first purpose, you will need to create an Azure Service Principal. After creating it, take note of the Azure AD application’s clientID (a UUID), and run the following script with the Azure CLI:

# Set the client ID of the app you created
CLIENT_ID="..."
# Scope of the resource, usually in the format:
# `/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.EventGrid/topics/{topicName}`
SCOPE="..."
# First ensure that Azure Resource Manager provider is registered for Event Grid
az provider register --namespace "Microsoft.EventGrid"
az provider show --namespace "Microsoft.EventGrid" --query "registrationState"
# Give the SP needed permissions so that it can create event subscriptions to Event Grid
az role assignment create --assignee "$CLIENT_ID" --role "EventGrid EventSubscription Contributor" --scopes "$SCOPE"

For the second purpose, first download a script:

curl -LO "https://raw.githubusercontent.com/dapr/components-contrib/master/.github/infrastructure/conformance/azure/setup-eventgrid-sp.ps1"

Then, using PowerShell (pwsh), run:

# Set the client ID of the app you created
$clientId = "..."
# Authenticate with the Microsoft Graph
# You may need to add the -TenantId flag to the next command if needed
Connect-MgGraph -Scopes "Application.Read.All","Application.ReadWrite.All"
./setup-eventgrid-sp.ps1 $clientId

Note: if your directory does not have a Service Principal for the application “Microsoft.EventGrid”, you may need to run the command Connect-MgGraph and sign in as an admin for the Azure AD tenant (this is related to permissions on the Azure AD directory, and not the Azure subscription). Otherwise, please ask your tenant’s admin to sign in and run this PowerShell command: New-MgServicePrincipal -AppId "4962773b-9cdb-44cf-a8bf-237846a00ab7" (the UUID is a constant)

Testing locally

• Install ngrok
• Run locally using a custom port, for example 9000, for handshakes

# Using port 9000 as an example
ngrok http --host-header=localhost 9000

• Configure the ngrok’s HTTPS endpoint and the custom port to input binding metadata
• Run Dapr

# Using default ports for .NET core web api and Dapr as an example
dapr run --app-id dotnetwebapi --app-port 5000 --dapr-http-port 3500 dotnet run

Testing on Kubernetes

Azure Event Grid requires a valid HTTPS endpoint for custom webhooks; self-signed certificates aren’t accepted. In order to enable traffic from the public internet to your app’s Dapr sidecar you need an ingress controller enabled with Dapr. There’s a good article on this topic: Kubernetes NGINX ingress controller with Dapr.

To get started, first create a dapr-annotations.yaml file for Dapr annotations:

controller:
  podAnnotations:
    dapr.io/enabled: "true"
    dapr.io/app-id: "nginx-ingress"
    dapr.io/app-port: "80"

Then install the NGINX ingress controller to your Kubernetes cluster with Helm 3 using the annotations:

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update
helm install nginx-ingress ingress-nginx/ingress-nginx -f ./dapr-annotations.yaml -n default
# Get the public IP for the ingress controller
kubectl get svc -l component=controller -o jsonpath='Public IP is: {.items[0].status.loadBalancer.ingress[0].ip}{"\n"}'

If deploying to Azure Kubernetes Service, you can follow the official Microsoft documentation for rest of the steps:

• Add an A record to your DNS zone
• Install cert-manager
• Create a CA cluster issuer

Final step for enabling communication between Event Grid and Dapr is to define http and custom port to your app’s service and an ingress in Kubernetes. This example uses a .NET Core web api and Dapr default ports and custom port 9000 for handshakes.

# dotnetwebapi.yaml
kind: Service
apiVersion: v1
metadata:
  name: dotnetwebapi
  labels:
    app: dotnetwebapi
spec:
  selector:
    app: dotnetwebapi
  ports:
    - name: webapi
      protocol: TCP
      port: 80
      targetPort: 80
    - name: dapr-eventgrid
      protocol: TCP
      port: 9000
      targetPort: 9000
  type: ClusterIP
---
  apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    name: eventgrid-input-rule
    annotations:
      kubernetes.io/ingress.class: nginx
      cert-manager.io/cluster-issuer: letsencrypt
  spec:
    tls:
      - hosts:
        - dapr.<your custom domain>
        secretName: dapr-tls
    rules:
      - host: dapr.<your custom domain>
        http:
          paths:
            - path: /api/events
              backend:
                serviceName: dotnetwebapi
                servicePort: 9000
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: dotnetwebapi
  labels:
    app: dotnetwebapi
spec:
  replicas: 1
  selector:
    matchLabels:
      app: dotnetwebapi
  template:
    metadata:
      labels:
        app: dotnetwebapi
      annotations:
        dapr.io/enabled: "true"
        dapr.io/app-id: "dotnetwebapi"
        dapr.io/app-port: "5000"
    spec:
      containers:
      - name: webapi
        image: <your container image>
        ports:
        - containerPort: 5000
        imagePullPolicy: Always

Deploy the binding and app (including ingress) to Kubernetes

# Deploy Dapr components
kubectl apply -f eventgrid.yaml
# Deploy your app and Nginx ingress
kubectl apply -f dotnetwebapi.yaml

Note: This manifest deploys everything to Kubernetes’ default namespace.

Troubleshooting possible issues with Nginx controller

After initial deployment the “Daprized” Nginx controller can malfunction. To check logs and fix issue (if it exists) follow these steps.

$ kubectl get pods -l app=nginx-ingress
NAME                                                   READY   STATUS    RESTARTS   AGE
nginx-nginx-ingress-controller-649df94867-fp6mg        2/2     Running   0          51m
nginx-nginx-ingress-default-backend-6d96c457f6-4nbj5   1/1     Running   0          55m
$ kubectl logs nginx-nginx-ingress-controller-649df94867-fp6mg nginx-ingress-controller
# If you see 503s logged from calls to webhook endpoint '/api/events' restart the pod
# .."OPTIONS /api/events HTTP/1.1" 503..
$ kubectl delete pod nginx-nginx-ingress-controller-649df94867-fp6mg
# Check the logs again - it should start returning 200
# .."OPTIONS /api/events HTTP/1.1" 200..

Related links

• Basic schema for a Dapr component
• Bindings building block
• How-To: Trigger application with input binding
• How-To: Use bindings to interface with external resources
• Bindings API reference

Last modified February 8, 2023: Updated docs for Event Grid for Dapr 1.10 (#3152) (8ac50eb1)