Aspire.Hosting.Maui

Aspire.Hosting.Maui

This library provides support for running .NET MAUI applications within an Aspire application model. It enables local development and debugging of MAUI apps alongside other services in your distributed application.

Getting Started

Adding a MAUI Application

Add a MAUI project to your Aspire app host:

var builder = DistributedApplication.CreateBuilder(args);

var mauiApp = builder.AddMauiProject("mauiapp", "../MauiApp/MauiApp.csproj");

Adding Platform Targets

Add specific platform targets for your MAUI application:

// Windows
mauiApp.AddWindowsDevice();

// macOS Catalyst
mauiApp.AddMacCatalystDevice();

// iOS Simulator
mauiApp.AddiOSSimulator();

// iOS Device
mauiApp.AddiOSDevice();

// Android Device
mauiApp.AddAndroidDevice();

// Android Emulator
mauiApp.AddAndroidEmulator();

You can optionally specify custom names and device/simulator IDs:

mauiApp.AddWindowsDevice("my-windows-app");

// iOS with specific simulator UDID
mauiApp.AddiOSSimulator("iphone-15-sim", "E25BBE37-69BA-4720-B6FD-D54C97791E79");

// iOS with specific device UDID (requires device provisioning)
mauiApp.AddiOSDevice("my-iphone", "00008030-001234567890123A");

// Android with specific emulator
mauiApp.AddAndroidEmulator("pixel-7-emulator", "Pixel_7_API_33");

// Android with specific device serial
mauiApp.AddAndroidDevice("my-pixel", "abc12345");

Note on Device/Simulator ID Validation: The iOS methods include validation to help detect common mistakes:

• AddiOSDevice() will fail at startup if you pass a GUID-format ID (which is typical for Simulator UDIDs)
• AddiOSSimulator() will fail at startup if you pass a non-GUID format ID (which is typical for device UDIDs)

These validation errors appear in the dashboard when you try to start the resource, making it clear if you've accidentally swapped device and simulator IDs.

OpenTelemetry Connectivity for Mobile Platforms

Mobile devices, Android emulators, and iOS simulators cannot reach localhost where the Aspire dashboard's OTLP endpoint typically runs. This library provides a simple way to configure OpenTelemetry connectivity using dev tunnels.

Using Dev Tunnel

Automatically create and configure a dev tunnel for the dashboard's OTLP endpoint. This is needed when running a .NET MAUI app on:

• Android emulator or device
• iOS simulator or device

You should not need this when running on Windows or Mac Catalyst (they can access localhost directly).

// Android emulator with OTLP dev tunnel
mauiApp.AddAndroidEmulator()
    .WithOtlpDevTunnel();

// iOS simulator with OTLP dev tunnel
mauiApp.AddiOSSimulator()
    .WithOtlpDevTunnel();

// iOS device with OTLP dev tunnel
mauiApp.AddiOSDevice()
    .WithOtlpDevTunnel();

When WithOtlpDevTunnel() is not added, things will still work, however tracing, metrics and telemetry data will not be complete.

This method automatically:

• Resolves the dashboard's OTLP endpoint from configuration
• Creates a dev tunnel for it
• Configures the MAUI platform to use the tunneled endpoint
• Handles all service discovery and environment variable configuration

Requirements:

• Aspire.Hosting.DevTunnels package must be referenced
• Dev tunnel CLI must be installed (automatic prompt if missing)
• User must be logged in to dev tunnel service (automatic prompt if needed)

Environment Variables Set

When you configure OTLP with dev tunnel, the following environment variables are automatically set:

• OTEL_EXPORTER_OTLP_ENDPOINT: The dev tunnel URL for the OTLP endpoint
• OTEL_EXPORTER_OTLP_PROTOCOL: Set to grpc (standard Aspire configuration)
• OTEL_SERVICE_NAME: The resource name
• OTEL_RESOURCE_ATTRIBUTES: Service instance ID

Example: Complete Aspire App with MAUI

var builder = DistributedApplication.CreateBuilder(args);

// Add backend services
var apiService = builder.AddProject<Projects.ApiService>("apiservice");

// Create a dev tunnel for the API service
var apiTunnel = builder.AddDevTunnel("api-tunnel")
    .WithAnonymousAccess()
    .WithReference(apiService.GetEndpoint("https"));

// Add MAUI app with multiple platform targets
var mauiApp = builder.AddMauiProject("mauiapp", "../MauiApp/MauiApp.csproj");

// Windows - can access localhost directly
mauiApp.AddWindowsDevice()
    .WithReference(apiService);

// Android Emulator - needs dev tunnels for both API and OTLP
mauiApp.AddAndroidEmulator()
    .WithOtlpDevTunnel() // For telemetry
    .WithReference(apiService, apiTunnel); // For API calls

// Android Device - same configuration
mauiApp.AddAndroidDevice()
    .WithOtlpDevTunnel()
    .WithReference(apiService, apiTunnel);

// iOS Simulator - needs dev tunnels for both API and OTLP
mauiApp.AddiOSSimulator()
    .WithOtlpDevTunnel() // For telemetry
    .WithReference(apiService, apiTunnel); // For API calls

// iOS Device - same configuration
mauiApp.AddiOSDevice()
    .WithOtlpDevTunnel()
    .WithReference(apiService, apiTunnel);

builder.Build().Run();

Platform-Specific Notes

iOS

Finding Simulator UDIDs:

# Using simctl
/Applications/Xcode.app/Contents/Developer/usr/bin/simctl list

# Or use Xcode: Window > Devices and Simulators

Device Requirements:

• iOS development requires macOS
• Physical devices require provisioning: Microsoft Learn - iOS Device Provisioning
• Find device UDID in Xcode: Window > Devices and Simulators

Android

Finding Emulator Names:

# List all available Android virtual devices
%ANDROID_HOME%\emulator\emulator.exe -list-avds

# Or use Android Studio: Tools > Device Manager

Finding Device Serials:

# List connected Android devices
adb devices

Build Queue

When multiple MAUI platform targets reference the same project (e.g., Android, iOS, and Mac Catalyst all using the same .csproj), MSBuild cannot handle concurrent builds of the same project file. The hosting integration automatically serializes these builds using a per-project queue.

How It Works

1. When you start multiple platform resources simultaneously, only one builds at a time
2. Other platforms show a "Queued" state in the dashboard while waiting
3. Each build shows a "Building" state with live MSBuild output in the resource logs
4. After a build completes and the app launches, the next queued build starts
5. You can click Stop on a queued or building resource to cancel it — the resource shows an "Exited" state with an orange indicator

Key Behaviors

• Per-project serialization: The queue is scoped to each MauiProjectResource. If you have two separate MAUI projects, they build in parallel. Only platform targets sharing the same project are serialized.
• Cancel support: Clicking Stop on a Queued resource removes it from the queue. Clicking Stop on a Building resource kills the dotnet build process.
• Restart after cancel: You can start a cancelled resource again — it re-enters the queue.
• Build timeout: Builds that take longer than 10 minutes are automatically cancelled to prevent a hung build from blocking the queue.
• DCP launch handoff: After the serialized build completes for the AppHost configuration and platform MSBuild properties, DCP launches the already-built app with build and restore disabled so the next queued platform can build without overlapping shared output writes.

Architecture

The build queue is implemented via:

• MauiBuildQueueAnnotation: Added to the parent MauiProjectResource, holds a SemaphoreSlim(1,1) and per-resource cancellation tokens
• MauiBuildQueueEventSubscriber: Subscribes to BeforeResourceStartedEvent, manages the queue, runs dotnet build as a subprocess, and replaces the default Stop command with a queue-aware version
• MauiBuildInfoAnnotation: Attached to each platform resource with the project path, working directory, target framework, configuration, and platform MSBuild properties used for the build subprocess
• ProjectLaunchArgsOverrideAnnotation: A core Aspire.Hosting annotation that overrides DCP's default dotnet run args, enabling dotnet build --no-restore /t:Run -p:NoBuild=true for MAUI projects after the serialized pre-build

Requirements

• .NET 10.0 or later
• MAUI workload must be installed: dotnet workload install maui
• Platform-specific SDKs:
  • Windows: Windows SDK 10.0.19041.0 or later
  • macOS: Xcode with command-line tools
  • Android: Android SDK via Visual Studio or Android Studio

Feedback & Issues

Please file issues at https://github.com/microsoft/aspire/issues