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
LiteBus.PostgreSql -> shared PostgreSQL schema infrastructure for inbox/outbox stores

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, storage contract interfaces	Runtime.Abstractions	none
LiteBus.Messaging	Message registry, mediator, descriptor builders, default serializer, 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	Inbox 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.Extensions.Microsoft.Hosting	Inbox processor background service, host options, health checks	Inbox, Runtime.Extensions.Microsoft.DependencyInjection	Microsoft.Extensions.Hosting.Abstractions, Microsoft.Extensions.Diagnostics.HealthChecks
LiteBus.Inbox.PostgreSql	Raw Npgsql inbox store and schema helper	Inbox.Abstractions, LiteBus.PostgreSql	Npgsql
LiteBus.Inbox.PostgreSql.Extensions.Microsoft.Hosting	Opt-in PostgreSQL inbox schema bootstrap hosted service	Inbox.PostgreSql, Microsoft DI runtime adapter	Microsoft.Extensions.Hosting.Abstractions
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.Extensions.Microsoft.Hosting	Outbox processor background service, host options, health checks	Outbox, Runtime.Extensions.Microsoft.DependencyInjection	Microsoft.Extensions.Hosting.Abstractions, Microsoft.Extensions.Diagnostics.HealthChecks
LiteBus.Outbox.PostgreSql	Raw Npgsql outbox store and schema helper	Outbox.Abstractions, LiteBus.PostgreSql	Npgsql
LiteBus.Outbox.PostgreSql.Extensions.Microsoft.Hosting	Opt-in PostgreSQL outbox schema bootstrap hosted service	Outbox.PostgreSql, Microsoft DI runtime adapter	Microsoft.Extensions.Hosting.Abstractions
LiteBus.PostgreSql	Shared PostgreSQL identifier quoting, schema version metadata, advisory locks	none	Npgsql
LiteBus.*.Extensions.Microsoft.Hosting	Processor host IHostedService wrappers and health checks	Module package, Microsoft DI runtime adapter	Microsoft hosting and health-check packages
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 storage 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

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);
    });
});

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.

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.EnsureAsync / PostgreSqlOutboxSchema.EnsureAsync, copy GetCreateScript into your migration tool, or enable opt-in host bootstrap. See PostgreSQL Schema Management.

Dependency Rules

• Query packages do not depend on inbox or outbox packages.
• PostgreSQL packages do not depend on EF Core.
• Inbox and outbox 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 contracts use names and versions. They do not store assembly-qualified type names.
• Closed generic messages are supported when each closed type is registered. Open generic contracts are not supported.