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In-Memory Transport

The in-memory transport is included with Dispatch and is ideal for testing, development, and single-process scenarios.

Before You Start​

Quick Start​

builder.Services.AddDispatch(typeof(Program).Assembly);
builder.Services.AddInMemoryTransport("inmemory");

Configuration​

builder.Services.AddDispatch(typeof(Program).Assembly);
builder.Services.AddInMemoryTransport("inmemory", options =>
{
    // Channel capacity for bounded message queue (default: 1000)
    // Producers will wait when capacity is reached
    options.ChannelCapacity = 2000;
});

Configuration Options​

OptionDefaultDescription
ChannelCapacity1000Maximum messages in the bounded channel. When reached, producers wait for space.

Testing Scenarios​

The in-memory transport provides properties and methods specifically designed for testing:

var registry = serviceProvider.GetRequiredService<TransportRegistry>();
var adapter = (InMemoryTransportAdapter)registry.GetTransportAdapter("inmemory")!;

// Inspect sent messages (keyed by message ID)
IReadOnlyDictionary<string, IDispatchMessage> messages = adapter.SentMessages;

// Clear messages between tests
adapter.ClearSentMessages();

// Check transport state
bool isRunning = adapter.IsRunning;

Add using Excalibur.Dispatch.Transport; to access TransportRegistry and InMemoryTransportAdapter.

Health Checks​

The in-memory transport implements ITransportHealthChecker for integration with ASP.NET Core health checks:

services.AddHealthChecks()
    .AddTransportHealthChecks();

Health status is determined by:

  • Healthy: Transport is running with acceptable failure rate
  • Degraded: Running but failure rate exceeds 10%
  • Unhealthy: Transport is not running

Limitations​

  • No persistence — messages are lost on restart
  • Single-process only — no network communication
  • Not suitable for production distributed scenarios

Next Steps​

See Also​