Aspire Azure Functions integration (Preview)

Includes: Hosting integration only — Client integration not included

Azure Functions is a serverless solution that allows you to write less code, maintain less infrastructure, and save on costs. The Aspire Azure Functions integration enables you to develop, debug, and orchestrate an Azure Functions .NET project as part of the AppHost.

It's expected that you've installed the required Azure tooling:

Supported scenarios

The Aspire Azure Functions integration has several key supported scenarios. This section outlines the scenarios and provides details related to the implementation of each approach.

Supported triggers

The following table lists the supported triggers for Azure Functions in the Aspire integration:

Deployment

Currently, deployment is supported only to containers on Azure Container Apps (ACA) using the SDK container publish function in Microsoft.Azure.Functions.Worker.Sdk. This deployment methodology doesn't currently support KEDA-based autoscaling.

Configure external HTTP endpoints

To make HTTP triggers publicly accessible, call the WithExternalHttpEndpoints API on the AzureFunctionsProjectResource. For more information, see Add Azure Functions resource.

Azure Function project constraints

The Aspire Azure Functions integration has the following project constraints:

• You must target .NET 8.0 or later.
• You must use a .NET 9 SDK.
• It currently only supports .NET workers with the isolated worker model.
• Requires the following NuGet packages:
  • 📦 Microsoft.Azure.Functions.Worker: Use the FunctionsApplicationBuilder.
  • 📦 Microsoft.Azure.Functions.Worker.Sdk: Adds support for dotnet run and azd publish.
  • 📦 Microsoft.Azure.Functions.Http.AspNetCore: Adds HTTP trigger-supporting APIs.

Hosting integration

The Azure Functions hosting integration models an Azure Functions resource as the AzureFunctionsProjectResource (subtype of ProjectResource) type. To access this type and APIs that allow you to add it to your AppHost project install the 📦 Aspire.Hosting.Azure.Functions NuGet package.

dotnet add package Aspire.Hosting.Azure.Functions --prerelease

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

For more information, see dotnet add package or Manage package dependencies in .NET applications.

Add Azure Functions resource

In your AppHost project, call AddAzureFunctionsProject on the builder instance to add an Azure Functions resource:

var builder = DistributedApplication.CreateBuilder(args);

var functions = builder.AddAzureFunctionsProject<Projects.ExampleFunctions>("functions")
                       .WithExternalHttpEndpoints();

builder.AddProject<Projects.ExampleProject>()
       .WithReference(functions)
       .WaitFor(functions);

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

When Aspire adds an Azure Functions project resource the AppHost, as shown in the preceding example, the functions resource can be referenced by other project resources. The WithReference method configures a connection in the ExampleProject named "functions". If the Azure Resource was deployed and it exposed an HTTP trigger, its endpoint would be external due to the call to WithExternalHttpEndpoints. For more information, see Reference resources.

Add Azure Functions resource with host storage

If you want to modify the default host storage account that the Azure Functions host uses, call the WithHostStorage method on the Azure Functions project resource:

var builder = DistributedApplication.CreateBuilder(args);

var storage = builder.AddAzureStorage("storage")
                     .RunAsEmulator();

var functions = builder.AddAzureFunctionsProject<Projects.ExampleFunctions>("functions")
                       .WithHostStorage(storage);

builder.AddProject<Projects.ExampleProject>()
       .WithReference(functions)
       .WaitFor(functions);

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

The preceding code relies on the 📦 Aspire.Hosting.Azure.Storage NuGet package to add an Azure Storage resource that runs as an emulator. The storage resource is then passed to the WithHostStorage API, explicitly setting the host storage to the emulated resource.

var builder = DistributedApplication.CreateBuilder(args);

var storage = builder.AddAzureStorage("storage");

builder.AddAzureFunctionsProject<Projects.ExampleFunctions>("functions")
       .WithHostStorage(storage)
       .WithRoleAssignments(storage, StorageBuiltInRole.StorageBlobDataReader,
                                    StorageBuiltInRole.StorageQueueDataReader);

Reference resources in Azure Functions

To reference other Azure resources in an Azure Functions project, chain a call to WithReference on the Azure Functions project resource and provide the resource to reference:

var builder = DistributedApplication.CreateBuilder(args);

var storage = builder.AddAzureStorage("storage").RunAsEmulator();
var blobs = storage.AddBlobs("blobs");

builder.AddAzureFunctionsProject<Projects.ExampleFunctions>("functions")
       .WithHostStorage(storage)
       .WithReference(blobs);

builder.Build().Run();

The preceding code adds an Azure Storage resource to the AppHost and references it in the Azure Functions project. The blobs resource is added to the storage resource and then referenced by the functions resource. The connection information required to connect to the blobs resource is automatically injected into the Azure Functions project and enables the project to define a BlobTrigger that relies on blobs resource.

See also

• Aspire integrations
• Aspire GitHub repo
• Azure Functions documentation
• Aspire and Functions image gallery sample