Dependency Graph

Dependency Graph

LiteBus is split into small packages so applications can reference only the modules they run. The graph has four layers: runtime, messaging, semantic modules, and optional infrastructure.

Layer Map

Runtime.Abstractions
  -> Runtime
    -> Runtime.Extensions.Microsoft.DependencyInjection
    -> Runtime.Extensions.Autofac

Messaging.Abstractions
  -> Messaging
    -> Messaging.Extensions.Microsoft.DependencyInjection
    -> Messaging.Extensions.Autofac

Commands.Abstractions -> Commands
Queries.Abstractions  -> Queries
Events.Abstractions   -> Events

Inbox.Abstractions -> Inbox -> Inbox.PostgreSql
Outbox.Abstractions -> Outbox -> Outbox.PostgreSql

Commands/Queries/Events/Inbox/Outbox depend on Messaging and Runtime.Abstractions.
Storage packages depend on their abstraction package and the external store client.
DI extension packages depend on the module package and the matching runtime adapter.

Package Table

Package	Role	Project dependencies	External dependencies
LiteBus.Runtime.Abstractions	DI-neutral service registration contracts	none	none
LiteBus.Runtime	Default module registry and dependency descriptor handling	Runtime.Abstractions	none
LiteBus.Runtime.Extensions.Microsoft.DependencyInjection	Microsoft DI adapter	Runtime	Microsoft.Extensions.DependencyInjection.Abstractions
LiteBus.Runtime.Extensions.Autofac	Autofac adapter	Runtime	Autofac
LiteBus.Messaging.Abstractions	Handler contracts, mediation contracts, execution context, durable contract contracts	Runtime.Abstractions	none
LiteBus.Messaging	Message registry, mediator, descriptor builders, default serializer, durable contract registry	Messaging.Abstractions, Runtime.Abstractions	System.Text.Json from the BCL
LiteBus.Commands.Abstractions	Command contracts, command handlers, command mediation settings	Messaging.Abstractions	none
LiteBus.Commands	Command mediator and command module	Commands.Abstractions, Messaging, Runtime.Abstractions	none
LiteBus.Queries.Abstractions	Query contracts, stream query contracts, query handlers	Messaging.Abstractions	none
LiteBus.Queries	Query mediator and query module	Queries.Abstractions, Messaging, Runtime.Abstractions	none
LiteBus.Events.Abstractions	Event contracts, event handlers, event mediation settings	Messaging.Abstractions	none
LiteBus.Events	Event mediator and event module	Events.Abstractions, Messaging, Runtime.Abstractions	none
LiteBus.Inbox.Abstractions	Durable command scheduler contracts, envelopes, processor contracts, store roles	Commands.Abstractions, Messaging.Abstractions	none
LiteBus.Inbox	Scheduler, inbox processor, inbox module	Commands.Abstractions, Inbox.Abstractions, Messaging, Runtime.Abstractions	none
LiteBus.Inbox.PostgreSql	Raw Npgsql inbox store and schema helper	Inbox.Abstractions	Npgsql
LiteBus.Outbox.Abstractions	Outbox writer contracts, envelopes, processor contracts, dispatcher contract, store roles	Messaging.Abstractions	none
LiteBus.Outbox	Outbox writer, integration outbox, outbox processor, LiteBus event dispatcher, outbox module	Events.Abstractions, Messaging, Outbox.Abstractions, Runtime.Abstractions	none
LiteBus.Outbox.PostgreSql	Raw Npgsql outbox store and schema helper	Outbox.Abstractions	Npgsql
LiteBus.*.Extensions.Microsoft.DependencyInjection	Module registration adapters for Microsoft DI	Module package, Microsoft DI runtime adapter	Microsoft DI adapter dependency only
LiteBus.*.Extensions.Autofac	Module registration adapters for Autofac	Module package, Autofac runtime adapter	Autofac adapter dependency only
LiteBus	Aggregate package for core modules and durable modules	Commands, Queries, Events, Messaging, Inbox, Outbox, and abstractions	none beyond referenced packages

Test and Tooling Dependencies

Test-only packages live under tests/Directory.Packages.props.

Package	Used for
xunit, xunit.runner.visualstudio	Unit and integration test execution
AwesomeAssertions	Test assertions
Microsoft.NET.Test.Sdk	.NET test host
coverlet.collector, coverlet.msbuild	Coverage collection
Testcontainers.PostgreSql	PostgreSQL integration tests
Npgsql	PostgreSQL integration tests
BenchmarkDotNet	Benchmark project package, declared by the benchmark project

The PostgreSQL integration tests require Docker because Testcontainers starts postgres:16-alpine during the test run.

Module Setup Options

Core Mediators

builder.Services.AddLiteBus(liteBus =>
{
    liteBus.AddCommandModule(commands =>
    {
        commands.RegisterFromAssembly(typeof(Program).Assembly);
    });

    liteBus.AddQueryModule(queries =>
    {
        queries.RegisterFromAssembly(typeof(Program).Assembly);
    });

    liteBus.AddEventModule(events =>
    {
        events.RegisterFromAssembly(typeof(Program).Assembly);
    });
});

Durable Command Inbox

builder.Services.AddLiteBus(liteBus =>
{
    liteBus.AddCommandInboxModule(inbox =>
    {
        inbox.Contracts.Register<ProcessPaymentCommand>(
            "payments.commands.process-payment",
            version: 1);

        inbox.UseProcessorOptions(new CommandInboxProcessorOptions
        {
            BatchSize = 50,
            LeaseDuration = TimeSpan.FromMinutes(2)
        });
    });
});

The inbox module registers ICommandScheduler and ICommandInboxProcessor. A store module or application registration must provide ICommandInboxWriter, ICommandInboxLeaseStore, and ICommandInboxStateStore.

Durable Outbox

builder.Services.AddLiteBus(liteBus =>
{
    liteBus.AddOutboxModule(outbox =>
    {
        outbox.Contracts.Register<OrderSubmittedIntegrationEvent>(
            "orders.events.order-submitted",
            version: 1);

        outbox.UseProcessorOptions(new OutboxProcessorOptions
        {
            BatchSize = 100,
            LeaseDuration = TimeSpan.FromMinutes(2)
        });
    });
});

The outbox module registers IOutboxWriter, IIntegrationOutbox, and IOutboxProcessor. It registers a dispatcher only when UseLiteBusEventDispatcher() is called. Broker dispatchers should register IOutboxDispatcher themselves.

PostgreSQL Stores

var dataSource = NpgsqlDataSource.Create(connectionString);

builder.Services.AddLiteBus(liteBus =>
{
    liteBus.AddPostgreSqlCommandInboxStore(postgres =>
    {
        postgres.UseDataSource(dataSource);
        postgres.UseOptions(new PostgreSqlInboxStoreOptions
        {
            SchemaName = "app",
            TableName = "litebus_inbox_commands"
        });
    });

    liteBus.AddPostgreSqlOutboxStore(postgres =>
    {
        postgres.UseDataSource(dataSource);
        postgres.UseOptions(new PostgreSqlOutboxStoreOptions
        {
            SchemaName = "app",
            TableName = "litebus_outbox_messages"
        });
    });
});

Call PostgreSqlInboxSchema.CreateIfNotExistsAsync and PostgreSqlOutboxSchema.CreateIfNotExistsAsync during startup or replace those helpers with migrations owned by the application.

Dependency Rules

• Query packages do not depend on durable inbox or outbox packages.
• PostgreSQL packages do not depend on EF Core.
• Durable abstractions do not depend on PostgreSQL, broker clients, or hosting packages.
• The command inbox schedules future command execution. The outbox stores facts for later publication.
• Stable durable contracts use names and versions. They do not store assembly-qualified type names.
• Closed generic durable messages are supported when each closed type is registered. Open generic durable contracts are not supported.