Azure Web PubSub integration

Azure Web PubSub is a fully managed real-time messaging service that enables you to build real-time web applications using WebSockets and publish-subscribe patterns. The Aspire Azure Web PubSub integration enables you to connect to Azure Web PubSub instances from your applications.

Hosting integration

The Aspire Azure Web PubSub hosting integration models the Web PubSub resources as the following types:

• AzureWebPubSubResource: Represents an Azure Web PubSub resource, including connection information to the underlying Azure resource.
• AzureWebPubSubHubResource: Represents a Web PubSub hub settings resource, which contains the settings for a hub. For example, you can specify if the hub allows anonymous connections or add event handlers to the hub.

To access these types and APIs for expressing them within your AppHost project, install the 📦 Aspire.Hosting.Azure.WebPubSub NuGet package:

Aspire CLI

Aspire CLI — 添加 Aspire.Hosting.Azure.WebPubSub 包

aspire add azure-webpubsub

Aspire CLI 是交互式的；按提示选择合适的搜索结果：

Aspire CLI — 输出示例

Select an integration to add:

> azure-webpubsub (Aspire.Hosting.Azure.WebPubSub)
> Other results listed as selectable options...

注意

如果只有一个结果，会自动选择。仍需确认版本。

apphost.cs (C# file-based app)

C# — AppHost.cs

#:package Aspire.Hosting.Azure.WebPubSub@*

PackageReference (*.csproj)

XML — 添加 Aspire.Hosting.Azure.WebPubSub 包引用

<PackageReference Include="Aspire.Hosting.Azure.WebPubSub" Version="*" />

Add an Azure Web PubSub resource

To add an Azure Web PubSub resource to your AppHost project, call the AddAzureWebPubSub method providing a name:

C# — AppHost.cs

var builder = DistributedApplication.CreateBuilder(args);

var webPubSub = builder.AddAzureWebPubSub("web-pubsub");

builder.AddProject<Projects.ExampleProject>()
    .WithReference(webPubSub);

// After adding all resources, run the app...

The preceding code adds an Azure Web PubSub resource named web-pubsub to the AppHost project. The WithReference method passes the connection information to the ExampleProject project.

警告

When you call AddAzureWebPubSub, it implicitly calls AddAzureProvisioning—which adds support for generating Azure resources dynamically during app startup. The app must configure the appropriate subscription and location. For more information, see Local provisioning: Configuration.

Add an Azure Web PubSub hub resource

When you add an Azure Web PubSub resource, you can also add a child hub resource. The hub resource is a logical grouping of connections and event handlers. To add an Azure Web PubSub hub resource to your AppHost project, chain a call to the AddHub method:

C# — AppHost.cs

var builder = DistributedApplication.CreateBuilder(args);

var worker = builder.AddProject<Projects.WorkerService>("worker")
    .WithExternalHttpEndpoints();

var webPubSub = builder.AddAzureWebPubSub("web-pubsub");
var messagesHub = webPubSub.AddHub(name: "messages", hubName: "messageHub");

// After adding all resources, run the app...

The preceding code adds an Azure Web PubSub hub resource named messages and a hub name of messageHub, which enables the addition of event handlers. To add an event handler, call the AddEventHandler:

C# — AppHost.cs

var builder = DistributedApplication.CreateBuilder(args);

var worker = builder.AddProject<Projects.WorkerService>("worker")
    .WithExternalHttpEndpoints();

var webPubSub = builder.AddAzureWebPubSub("web-pubsub");
var messagesHub = webPubSub.AddHub(name: "messages", hubName: "messageHub");

messagesHub.AddEventHandler(
    $"{worker.GetEndpoint("https")}/eventhandler/",
    systemEvents: ["connected"]);

// After adding all resources, run the app...

The preceding code adds a worker service project named worker with an external HTTP endpoint. The hub named messages resource is added to the web-pubsub resource, and an event handler is added to the messagesHub resource. The event handler URL is set to the worker service’s external HTTP endpoint. For more information, see Azure Web PubSub event handlers.

Connect to an existing Azure Web PubSub instance

You might have an existing Azure Web PubSub service that you want to connect to. You can chain a call to annotate that your AzureWebPubSubResource is an existing resource:

C# — AppHost.cs

var builder = DistributedApplication.CreateBuilder(args);

var existingPubSubName = builder.AddParameter("existingPubSubName");
var existingPubSubResourceGroup = builder.AddParameter("existingPubSubResourceGroup");

var webPubSub = builder.AddAzureWebPubSub("web-pubsub")
    .AsExisting(existingPubSubName, existingPubSubResourceGroup);

builder.AddProject<Projects.ExampleProject>()
    .WithReference(webPubSub);

// After adding all resources, run the app...

For more information on treating Azure Web PubSub resources as existing resources, see Use existing Azure resources.

注意

Alternatively, instead of representing an Azure Web PubSub resource, you can add a connection string to the AppHost. This approach is weakly-typed and doesn’t work with role assignments or infrastructure customizations.

Provisioning-generated Bicep

When you publish your app, Aspire provisioning APIs generate Bicep alongside the manifest file. Bicep is a domain-specific language for defining Azure resources. For more information, see Bicep Overview.

When you add an Azure Web PubSub resource, the following Bicep is generated:

web-pubsub.bicep

@description('The location for the resource(s) to be deployed.')
param location string = resourceGroup().location

param sku string = 'Free_F1'

param capacity int = 1

param messages_url_0 string

resource web_pubsub 'Microsoft.SignalRService/webPubSub@2024-03-01' = {
  name: take('webpubsub-${uniqueString(resourceGroup().id)}', 63)
  location: location
  properties: {
    disableLocalAuth: true
  }
  sku: {
    name: sku
    capacity: capacity
  }
  tags: {
    'aspire-resource-name': 'web-pubsub'
  }
}

resource messages 'Microsoft.SignalRService/webPubSub/hubs@2024-03-01' = {
  name: 'messages'
  properties: {
    eventHandlers: [
      {
        urlTemplate: messages_url_0
        userEventPattern: '*'
        systemEvents: [
          'connected'
        ]
      }
    ]
  }
  parent: web_pubsub
}

output endpoint string = 'https://${web_pubsub.properties.hostName}'

output name string = web_pubsub.name

The preceding Bicep is a module that provisions an Azure Web PubSub resource. Additionally, role assignments are created for the Azure resource in a separate module:

web-pubsub-roles.bicep

@description('The location for the resource(s) to be deployed.')
param location string = resourceGroup().location

param web_pubsub_outputs_name string

param principalType string

param principalId string

resource web_pubsub 'Microsoft.SignalRService/webPubSub@2024-03-01' existing = {
  name: web_pubsub_outputs_name
}

resource web_pubsub_WebPubSubServiceOwner 'Microsoft.Authorization/roleAssignments@2022-04-01' = {
  name: guid(web_pubsub.id, principalId, subscriptionResourceId('Microsoft.Authorization/roleDefinitions', '12cf5a90-567b-43ae-8102-96cf46c7d9b4'))
  properties: {
    principalId: principalId
    roleDefinitionId: subscriptionResourceId('Microsoft.Authorization/roleDefinitions', '12cf5a90-567b-43ae-8102-96cf46c7d9b4')
    principalType: principalType
  }
  scope: web_pubsub
}

The generated Bicep is a starting point and is influenced by changes to the provisioning infrastructure in C#. Customizations to the Bicep file directly will be overwritten, so make changes through the C# provisioning APIs to ensure they are reflected in the generated files.

Customize provisioning infrastructure

All Aspire Azure resources are subclasses of the AzureProvisioningResource type. This type enables the customization of the generated Bicep by providing a fluent API to configure the Azure resources using the ConfigureInfrastructure API:

C# — AppHost.cs

var builder = DistributedApplication.CreateBuilder(args);

builder.AddAzureWebPubSub("web-pubsub")
    .ConfigureInfrastructure(infra =>
    {
        var webPubSubService = infra.GetProvisionableResources()
                                    .OfType<WebPubSubService>()
                                    .Single();

        webPubSubService.Sku.Name = "Standard_S1";
        webPubSubService.Sku.Capacity = 5;
        webPubSubService.Tags.Add("ExampleKey", "Example value");
    });

The preceding code:

• Chains a call to the ConfigureInfrastructure API:
  • The infra parameter is an instance of the AzureResourceInfrastructure type.
  • The provisionable resources are retrieved by calling the GetProvisionableResources method.
  • The single WebPubSubService resource is retrieved.
  • The Sku object has its name and capacity properties set to Standard_S1 and 5, respectively.
  • A tag is added to the Web PubSub resource with a key of ExampleKey and a value of Example value.

There are many more configuration options available to customize the Web PubSub resource. For more information, see Azure.Provisioning customization.

Client integration

The Aspire Azure Web PubSub client integration is used to connect to an Azure Web PubSub service using the WebPubSubServiceClient. To get started with the Aspire Azure Web PubSub service client integration, install the 📦 Aspire.Azure.Messaging.WebPubSub NuGet package.

.NET CLI

.NET CLI — Add Aspire.Azure.Messaging.WebPubSub package

dotnet add package Aspire.Azure.Messaging.WebPubSub

Program.cs (C# file-based app)

Program.cs

#:package Aspire.Azure.Messaging.WebPubSub@*

PackageReference (*.csproj)

XML — Add Aspire.Azure.Messaging.WebPubSub package reference

<PackageReference Include="Aspire.Azure.Messaging.WebPubSub" Version="*" />

Supported Web PubSub client types

The following Web PubSub client types are supported by the library:

Azure client type	Azure options class	Aspire settings class
WebPubSubServiceClient	WebPubSubServiceClientOptions	AzureMessagingWebPubSubSettings

Add Web PubSub client

In the Program.cs file of your client-consuming project, call the AddAzureWebPubSubServiceClient extension method to register a WebPubSubServiceClient for use via the dependency injection container. The method takes a connection name parameter:

builder.AddAzureWebPubSubServiceClient(connectionName: "web-pubsub");

提示

The connectionName parameter must match the name used when adding the Web PubSub resource in the AppHost project. For more information, see Add an Azure Web PubSub resource.

After adding the WebPubSubServiceClient, you can retrieve the client instance using dependency injection:

public class ExampleService(WebPubSubServiceClient client)
{
    // Use client...
}

For more information, see:

• Azure.Messaging.WebPubSub documentation for examples on using the WebPubSubServiceClient.
• Dependency injection in .NET for details on dependency injection.

Add keyed Web PubSub client

There might be situations where you want to register multiple WebPubSubServiceClient instances with different connection names. To register keyed Web PubSub clients, call the AddKeyedAzureWebPubSubServiceClient method:

builder.AddKeyedAzureWebPubSubServiceClient(name: "messages");
builder.AddKeyedAzureWebPubSubServiceClient(name: "commands");

警告

When using keyed services, it’s expected that your Web PubSub resource configured two named hubs, one for the messages and one for the commands.

Then you can retrieve the client instances using dependency injection:

public class ExampleService(
    [KeyedService("messages")] WebPubSubServiceClient messagesClient,
    [KeyedService("commands")] WebPubSubServiceClient commandsClient)
{
    // Use clients...
}

For more information, see Keyed services in .NET.

Configuration

The Aspire Azure Web PubSub library provides multiple options to configure the Azure Web PubSub connection based on the requirements and conventions of your project. Either an Endpoint or a ConnectionString must be supplied.

Use a connection string

When using a connection string from the ConnectionStrings configuration section, you can provide the name of the connection string when calling AddAzureWebPubSubServiceClient:

builder.AddAzureWebPubSubServiceClient(
    "web-pubsub",
    settings => settings.HubName = "your_hub_name");

The connection information is retrieved from the ConnectionStrings configuration section. Two connection formats are supported:

• Service endpoint (recommended): Uses the service endpoint with DefaultAzureCredential.

  {
    "ConnectionStrings": {
      "web-pubsub": "https://{account_name}.webpubsub.azure.com"
    }
  }

• Connection string: Includes an access key.

  {
    "ConnectionStrings": {
      "web-pubsub": "Endpoint=https://{account_name}.webpubsub.azure.com;AccessKey={account_key}"
    }
  }

Use configuration providers

The library supports Microsoft.Extensions.Configuration. It loads settings from configuration using the Aspire:Azure:Messaging:WebPubSub key:

{
  "Aspire": {
    "Azure": {
      "Messaging": {
        "WebPubSub": {
          "DisableHealthChecks": true,
          "HubName": "your_hub_name"
        }
      }
    }
  }
}

Use inline delegates

You can configure settings inline:

builder.AddAzureWebPubSubServiceClient(
    "web-pubsub",
    settings => settings.DisableHealthChecks = true);

Observability and telemetry

Aspire integrations automatically set up Logging, Tracing, and Metrics configurations.

Logging

The Aspire Azure Web PubSub integration uses the following log categories:

• Azure
• Azure.Core
• Azure.Identity
• Azure.Messaging.WebPubSub

Tracing

The Aspire Azure Web PubSub integration will emit the following tracing activities using OpenTelemetry:

• Azure.Messaging.WebPubSub.*

Metrics

The Aspire Azure Web PubSub integration currently doesn’t support metrics by default due to limitations with the Azure SDK for .NET.