How to send events from Azure SignalR Service to Event Grid

  • Article

Azure Event Grid is a fully managed event routing service that provides uniform event consumption using a pub-sub model. In this guide, you use the Azure CLI to create an Azure SignalR Service, subscribe to connection events, then deploy a sample web application to receive the events. Finally, you can connect and disconnect and see the event payload in the sample application.

If you don't have an Azure subscription, create an Azure free account before you begin.

Prerequisites

  • The Azure CLI commands in this article are formatted for the Bash shell. If you're using a different shell like PowerShell or Command Prompt, you may need to adjust line continuation characters or variable assignment lines accordingly. This article uses variables to minimize the amount of command editing required.

Create a resource group

An Azure resource group is a logical container in which you deploy and manage your Azure resources. The command az group create creates a resource group named myResourceGroup in the eastus region. If you want to use a different name for your resource group, set RESOURCE_GROUP_NAME to a different value.

RESOURCE_GROUP_NAME=myResourceGroup

az group create --name $RESOURCE_GROUP_NAME --location eastus

Create a SignalR Service

Next, deploy an Azure Signals Service into the resource group with the following commands.

SIGNALR_NAME=SignalRTestSvc

az signalr create --resource-group $RESOURCE_GROUP_NAME --name $SIGNALR_NAME --sku Free_F1

Once the SignalR Service has been created, the Azure CLI returns output similar to the following example:

{
  "externalIp": "13.76.156.152",
  "hostName": "clitest.servicedev.signalr.net",
  "hostNamePrefix": "clitest",
  "id": "/subscriptions/28cf13e2-c598-4aa9-b8c8-098441f0827a/resourceGroups/clitest1/providers/Microsoft.SignalRService/SignalR/clitest",
  "location": "southeastasia",
  "name": "clitest",
  "provisioningState": "Succeeded",
  "publicPort": 443,
  "resourceGroup": "clitest1",
  "serverPort": 443,
  "sku": {
    "capacity": 1,
    "family": null,
    "name": "Free_F1",
    "size": "F1",
    "tier": "Free"
  },
  "tags": null,
  "type": "Microsoft.SignalRService/SignalR",
  "version": "1.0"
}

Create an event endpoint

In this section, you use a Resource Manager template located in a GitHub repository to deploy a prebuilt sample web application to Azure App Service. Later, you subscribe to your registry's Event Grid events and specify this app as the endpoint to which the events are sent.

To deploy the sample app, set SITE_NAME to a unique name for your web app, and execute the following commands. The site name must be unique within Azure because it forms part of the fully qualified domain name (FQDN) of the web app. In a later section, you navigate to the app's FQDN in a web browser to view your registry's events.

SITE_NAME=<your-site-name>

az deployment group create \
    --resource-group $RESOURCE_GROUP_NAME \
    --template-uri "https://raw.githubusercontent.com/Azure-Samples/azure-event-grid-viewer/master/azuredeploy.json" \
    --parameters siteName=$SITE_NAME hostingPlanName=$SITE_NAME-plan

Once the deployment succeeds (it might take a few minutes), open your browser, and then go to your web app to make sure it's running:

http://<your-site-name>.azurewebsites.net

Enable the Event Grid resource provider

  1. If you haven't previously used Event Grid in your Azure subscription, you might need to register the Event Grid resource provider. Run the following command to register the provider:

    az provider register --namespace Microsoft.EventGrid

  2. It might take a moment for the registration to finish. To check the status, run the following command:

    az provider show --namespace Microsoft.EventGrid --query "registrationState"

    When registrationState is Registered, you're ready to continue.

Subscribe to registry events

In Event Grid, you subscribe to a topic to tell it which events you want to track, and where to send them. The command az eventgrid event-subscription create subscribes to the Azure SignalR Service you created and specifies your web app's URL as the endpoint to which it should send events. The environment variables you populated in earlier sections are reused here, so no edits are required.

SIGNALR_SERVICE_ID=$(az signalr show --resource-group $RESOURCE_GROUP_NAME --name $SIGNALR_NAME --query id --output tsv)
APP_ENDPOINT=https://$SITE_NAME.azurewebsites.net/api/updates

az eventgrid event-subscription create \
    --name event-sub-signalr \
    --source-resource-id $SIGNALR_SERVICE_ID \
    --endpoint $APP_ENDPOINT

When the subscription is completed, you should see output similar to the following example:

{
  "deadLetterDestination": null,
  "destination": {
    "endpointBaseUrl": "https://$SITE_NAME.azurewebsites.net/api/updates",
    "endpointType": "WebHook",
    "endpointUrl": null
  },
  "filter": {
    "includedEventTypes": [
      "Microsoft.SignalRService.ClientConnectionConnected",
      "Microsoft.SignalRService.ClientConnectionDisconnected"
    ],
    "isSubjectCaseSensitive": null,
    "subjectBeginsWith": "",
    "subjectEndsWith": ""
  },
  "id": "/subscriptions/28cf13e2-c598-4aa9-b8c8-098441f0827a/resourceGroups/myResourceGroup/providers/Microsoft.SignalRService/SignalR/SignalRTestSvc/providers/Microsoft.EventGrid/eventSubscriptions/event-sub-signalr",
  "labels": null,
  "name": "event-sub-signalr",
  "provisioningState": "Succeeded",
  "resourceGroup": "myResourceGroup",
  "retryPolicy": {
    "eventTimeToLiveInMinutes": 1440,
    "maxDeliveryAttempts": 30
  },
  "topic": "/subscriptions/28cf13e2-c598-4aa9-b8c8-098441f0827a/resourceGroups/myResourceGroup/providers/microsoft.signalrservice/signalr/SignalRTestSvc",
  "type": "Microsoft.EventGrid/eventSubscriptions"
}

Trigger registry events

Switch to the service mode to Serverless Mode and set up a client connection to the SignalR Service. You can take Serverless Sample as a reference.

git clone git@github.com:aspnet/AzureSignalR-samples.git

cd samples/Management

# Start the negotiation server
# Negotiation server is responsible for generating access token for clients
cd NegotitationServer
dotnet user-secrets set Azure:SignalR:ConnectionString "<Connection String>"
dotnet run

# Use a separate command line
# Start a client
cd SignalRClient
dotnet run

View registry events

You've now connected a client to the SignalR Service. Navigate to your Event Grid Viewer web app, and you should see a ClientConnectionConnected event. If you terminate the client, you'll also see a ClientConnectionDisconnected event.