LiteBus Cheat Sheet

One-page reference for LiteBus v6. Install only the packages you use; register storage, dispatch, and processors inside nested inbox/outbox builders.

Mediators

Inject ICommandMediator, IQueryMediator, or IEventMediator. Handlers and pipeline stages (pre, post, error) are discovered by RegisterFromAssembly and resolved per mediation call.

await commandMediator.SendAsync(new CreateOrderCommand(orderId));
var order = await queryMediator.QueryAsync(new GetOrderQuery(orderId));
await eventMediator.PublishAsync(new OrderPlaced(orderId));

Module Registration

Prefer the ILiteBusBuilder overload for normal package-owned feature composition:

services.AddLiteBus(builder =>
{
    var assembly = typeof(Program).Assembly;

    builder.AddMessaging(messaging =>
        messaging.Contracts.Register<OrderPlaced>("orders.events.placed", 1));
    builder.AddCommands(c => c.RegisterFromAssembly(assembly));
    builder.AddQueries(q => q.RegisterFromAssembly(assembly));
    builder.AddEvents(e => e.RegisterFromAssembly(assembly));

    builder.AddInbox(inbox =>
    {
        inbox.Contracts.Register<ProcessPaymentCommand>("payments.process-payment", 1);
        inbox.UseInMemoryStorage();
        inbox.UseInProcessDispatch();
        inbox.EnableInboxProcessor(host => host.PollInterval = TimeSpan.FromSeconds(2));
    });

    builder.AddOutbox(outbox =>
    {
        outbox.Contracts.Register<OrderPlaced>("orders.events.placed", 1);
        outbox.UseInMemoryStorage();
        outbox.UseInProcessDispatch();
        outbox.EnableOutboxProcessor(host => host.PollInterval = TimeSpan.FromSeconds(2));
    });
});

Durable Messaging Entry Points

Intent	API	Package role
Accept command for later execution	`IInbox.AcceptAsync`	`LiteBus.Inbox`
Enqueue event for later publication	`IOutbox.EnqueueAsync`	`LiteBus.Outbox`
Schedule with future visibility	`InboxAcceptMetadata.Visibility` / `OutboxEnqueueMetadata.Visibility`	`MessageVisibility.At` or `MessageVisibility.After` on the writer item
Execute command now	`ICommandMediator.SendAsync`	`LiteBus.Commands`
Publish event now	`IEventMediator.PublishAsync`	`LiteBus.Events`

Only ICommand (no result) may be stored in the inbox. Analyzer LB1004 flags ICommand<TResult> at compile time.

Root Transport Composition

Register horizontal transport infrastructure once on ILiteBusBuilder. Dispatch and ingress extensions require and share it.

Extension	NuGet package
`AddAmqpTransport(...)`	`LiteBus.Transport.Amqp`
`AddKafkaTransport(...)`	`LiteBus.Transport.Kafka`
`AddAwsSqsTransport(...)`	`LiteBus.Transport.AwsSqs`
`AddAzureServiceBusTransport(...)`	`LiteBus.Transport.AzureServiceBus`
`AddInMemoryTransport()`	`LiteBus.Transport.InMemory`

Inbox Composition (`Use*` Extensions)

Extension	NuGet package
`UseInMemoryStorage()`	`LiteBus.Inbox.Storage.InMemory`
`UsePostgreSqlStorage(...)`	`LiteBus.Inbox.Storage.PostgreSql`
`UseEntityFrameworkCoreStorage(...)`	`LiteBus.Inbox.Storage.EntityFrameworkCore`
`UseInProcessDispatch()`	`LiteBus.Inbox.Dispatch.InProcess`
`UseAmqpDispatch(...)`	`LiteBus.Inbox.Dispatch.Amqp`
`UseAzureServiceBusDispatch(...)`	`LiteBus.Inbox.Dispatch.AzureServiceBus`
`UseAwsSqsDispatch(...)`	`LiteBus.Inbox.Dispatch.AwsSqs`
`UseKafkaDispatch(...)`	`LiteBus.Inbox.Dispatch.Kafka`
`UseInMemoryDispatch(...)`	`LiteBus.Inbox.Dispatch.InMemory`
`UseAmqpIngress(...)`	`LiteBus.Inbox.Ingress.Amqp`
`UseAzureServiceBusIngress(...)`	`LiteBus.Inbox.Ingress.AzureServiceBus`
`UseAwsSqsIngress(...)`	`LiteBus.Inbox.Ingress.AwsSqs`
`UseKafkaIngress(...)`	`LiteBus.Inbox.Ingress.Kafka`
`UseInMemoryIngress(...)`	`LiteBus.Inbox.Ingress.InMemory`
`EnableInboxProcessor(...)`	`LiteBus.Inbox` (registers `InboxProcessorBackgroundService` via manifest)
`EnableSaga(...)`	`LiteBus.Saga.InboxIntegration`

Outbox Composition (`Use*` Extensions)

Extension	NuGet package
`UseInMemoryStorage()`	`LiteBus.Outbox.Storage.InMemory`
`UsePostgreSqlStorage(...)`	`LiteBus.Outbox.Storage.PostgreSql`
`UseEntityFrameworkCoreStorage(...)`	`LiteBus.Outbox.Storage.EntityFrameworkCore`
`UseInProcessDispatch()`	`LiteBus.Outbox.Dispatch.InProcess`
`UseAmqpDispatch(...)`	`LiteBus.Outbox.Dispatch.Amqp`
`UseAzureServiceBusDispatch(...)`	`LiteBus.Outbox.Dispatch.AzureServiceBus`
`UseAwsSqsDispatch(...)`	`LiteBus.Outbox.Dispatch.AwsSqs`
`UseKafkaDispatch(...)`	`LiteBus.Outbox.Dispatch.Kafka`
`UseInMemoryDispatch(...)`	`LiteBus.Outbox.Dispatch.InMemory`
`EnableOutboxProcessor(...)`	`LiteBus.Outbox`

Accept and Enqueue Examples

var receipt = await inbox.AcceptAsync(
    InboxAcceptItem<ProcessPaymentCommand>.From(
        new ProcessPaymentCommand(paymentId, amount),
        InboxAcceptMetadata.Immediate with
        {
            Idempotency = new Idempotency.Keyed($"payment:{paymentId}"),
        }),
    cancellationToken);

var outboxReceipt = await outbox.EnqueueAsync(
    OutboxEnqueueItem<OrderPlaced>.WithTopic(new OrderPlaced(orderId), "orders.events"),
    cancellationToken);

PostgreSQL Storage (Nested)

builder.AddInbox(inbox =>
{
    inbox.Contracts.Register<ProcessPaymentCommand>("payments.process-payment", 1);
    inbox.UsePostgreSqlStorage(pg =>
    {
        pg.UseDataSource(dataSource);
        pg.EnsureSchemaCreationOnStartup(); // dev only; production uses migration-owned DDL
    });
    inbox.UseInProcessDispatch();
    inbox.EnableInboxProcessor();
});

Inbox and outbox use PostgreSQL schema version 3; saga uses version 2. Apply the ordered migration files for an existing v6 table. Tables from v5 or earlier require replacement or an application-owned data migration.

Health and Operations

builder.Services.AddLiteBusManagement(options =>
{
    options.FailHealthWhenNoProbes = false; // samples; production should use true (default)
    options.AuthorizationPolicy = "LiteBusOperator"; // production
    // options.AllowAnonymousManagement = true; // Development only
});
builder.Services.AddHealthChecks().AddLiteBus();
app.UseAuthentication();
app.UseAuthorization();
app.AddLiteBusManagementEndpoints();

OpenTelemetry

The aggregate LiteBus.Extensions.OpenTelemetry package is removed. Register each axis you export:

builder.Services.AddOpenTelemetry()
    .WithMetrics(m => m
        .AddLiteBusInboxMetrics()
        .AddLiteBusOutboxMetrics()
        .AddLiteBusTransportMetrics());

Instrument names on LiteBusInboxTelemetry, LiteBusOutboxTelemetry, and LiteBusTransportTelemetry are a public contract; renames are breaking changes.

Processor Options Worth Knowing

Option	Default	Notes
`HonorShutdownTokenOnPersist`	`false`	When `false`, terminal `PersistAsync` uses `CancellationToken.None` (safer against duplicate dispatch; shutdown may block). When `true`, passes the shutdown token (faster drain; duplicate-dispatch risk).
`DispatcherConcurrency`	`1`	Raise only when handlers are safe in parallel.
`LeaseHeartbeatInterval`	15s	Must be `<= LeaseDuration / 2`.

Naming Schemes

You see	Meaning
Folder / project `LiteBus.Inbox.Storage.PostgreSql`	Source layout
Namespace `LiteBus.Inbox.Storage.PostgreSql`	C# API
NuGet `LiteBus.Inbox.Storage.PostgreSql`	Package ID

Getting Started for a full walkthrough
Inbox and Outbox for durable messaging depth
Hosted services for manifest, probes, and management endpoints
Dependency Graph for package boundaries