Integrate Mocha with ASP.NET Core using the Mocha.Hosting package for health checks.

Hosting

The Mocha.Hosting package provides ASP.NET Core integrations for the message bus: health checks that verify end-to-end connectivity through serialization, transport, routing, and handler execution.

dotnet add package Mocha.Hosting

Health checks

Mocha integrates with the ASP.NET Core health checks system. The health check sends a HealthRequest message through the bus and waits for a HealthResponse. This verifies the full pipeline - serialization, transport, routing, and handler execution - not just that the broker is reachable.

Register the health check handler

On the bus builder, call .AddHealthCheck() to register the built-in HealthRequestHandler. This handler responds to HealthRequest messages with an "OK" response.

using Mocha;
using Mocha.Hosting;

var builder = WebApplication.CreateBuilder(args);

builder.Services
    .AddMessageBus()
    .AddHealthCheck() // Registers the HealthRequestHandler
    .AddMyApp()       // source-generated handler registration
    .AddRabbitMQ();

Add the health check to ASP.NET Core

Use the AddMessageBus() extension on IHealthChecksBuilder to register a health check that sends a request through the bus and verifies the response:

builder.Services
    .AddHealthChecks()
    .AddMessageBus(); // Sends HealthRequest via RequestAsync and checks the reply

Then map the health check endpoint:

var app = builder.Build();

app.MapHealthChecks("/health");

app.Run();

A GET /health request will now include the message bus status. If the bus cannot process and reply to the health request within the timeout, the check reports Unhealthy.

Target a specific endpoint

By default the health check uses the bus's default routing to deliver the HealthRequest. To target a specific endpoint (useful when you have multiple transports or want to verify a particular service), pass a URI:

builder.Services
    .AddHealthChecks()
    .AddMessageBus(new Uri("queue://my-service-health"));

The health check is registered with the "ready" and "live" tags, so you can use tag-based filtering to separate readiness from liveness probes:

app.MapHealthChecks("/health/ready", new()
{
    Predicate = check => check.Tags.Contains("ready")
});

app.MapHealthChecks("/health/live", new()
{
    Predicate = check => check.Tags.Contains("live")
});

Next steps

• Observability - Add OpenTelemetry tracing and metrics to the bus.
• Reliability - Configure outbox, inbox, and circuit breakers.
• Transports - Configure RabbitMQ, InMemory, and multi-transport setups.