Transport Axis Capability Catalog

LiteBus transport is the broker-facing publish and consume axis. Dispatch and ingress call transport contracts (ITransportPublisher, IMessageConsumer) but own durable storage, leasing, and processor policy.

Role in LiteBus

Outbox and inbox dispatch   -> ITransportPublisher.PublishAsync
Inbox ingress adapters      -> IMessageConsumer.StartAsync
Raw transport hosts         -> IMessageConsumer + TransportConsumerHandlerInvoker

Transport maps durable envelope metadata to canonical wire headers. It does not write inbox rows, lease envelopes, or run command and event mediators.

Capability Pages and Quality Bar

Every page in this folder is a reference contract and uses the same required sections:

Section	Required content
ID, Name, Maturity, Summary	Stable capability identity and tier
What it does	Runtime behavior and boundaries
Public surface	API tables with concrete types and members
Packages	Package and adapter ownership
Requires	Capability dependencies
Invariants	Behavior that must remain stable
Non-goals	Explicit exclusions
Observability	Verified meter, activity, and tag names from `LiteBus.Transport*`
Test coverage	Covered, Untested, and Out-of-scope
Deep docs	Axis and feature guides

manual-acknowledgement.md and ingress/amqp.md remain the depth benchmark for all pages.

Packages

Package	Dependency role	Purpose
`LiteBus.Transport.Abstractions`	Platform contracts	Contracts, canonical headers, ack model
`LiteBus.Transport`	Core implementation	Circuit breaker, tracing, header mapper, invoker
`LiteBus.Transport.Amqp`	Technology adapter	RabbitMQ and LavinMQ adapter
`LiteBus.Transport.Kafka`	Technology adapter	Kafka adapter
`LiteBus.Transport.AwsSqs`	Technology adapter	AWS SQS adapter
`LiteBus.Transport.AzureServiceBus`	Technology adapter	Azure Service Bus adapter
`LiteBus.Transport.InMemory`	Technology adapter	In-process channel adapter
`LiteBus.Transport.Extensions.OpenTelemetry`	Host adapter	`AddLiteBusTransportMetrics()`
`LiteBus.Transport.Amqp.Extensions.OpenTelemetry`	Host adapter	`AddLiteBusAmqpMetrics()` alias

Capability Index

ID	Name	Maturity	File
`transport.publish-consume-contracts`	Publish and consume contracts	GA	publish-consume-contracts.md
`transport.manual-acknowledgement`	Manual acknowledgement model	GA	manual-acknowledgement.md
`transport.canonical-headers`	Canonical wire headers	GA	canonical-headers.md
`transport.envelope-header-mapping`	Envelope to header mapping	GA	envelope-header-mapping.md
`transport.circuit-breaker`	Transport circuit breaker	GA	circuit-breaker.md
`transport.consumer-handler-invoker`	Consumer handler invoker	GA	consumer-handler-invoker.md
`transport.single-broker-registration`	Single broker registration	GA	single-broker-registration.md
`transport.tenant-routing`	Tenant routing strategy	GA	tenant-routing.md
`transport.tracing`	Publish and consume tracing	GA	tracing.md
`transport.metrics`	Circuit breaker metrics	GA	metrics.md
`transport.amqp`	AMQP transport	GA	amqp.md
`transport.kafka`	Kafka transport	GA	kafka.md
`transport.azure-service-bus`	Azure Service Bus transport	Beta	azure-service-bus.md
`transport.aws-sqs`	AWS SQS transport	Beta	aws-sqs.md
`transport.inmemory`	In-memory transport	GA	inmemory.md

Four-Executor Test Pattern

Transport reference pages use a four-executor test map:

Executor	Scope
`LiteBus.Transport.UnitTests`	Adapter and core unit behavior (`Amqp/`, `Kafka/`, `AwsSqs/`, `AzureServiceBus/`, `InMemory/`)
`LiteBus.Transport.IntegrationTests`	Transport wire tests (AMQP only in v6)
`LiteBus.Durable.IntegrationTests`	Dispatch and ingress hops that exercise transport through durable pipelines
Application host executor	Consumer application integration that composes LiteBus modules; repo helper package `LiteBus.Transport.IntegrationTesting` provides fixtures only and is not an executor

Custom adapter authors can reference the published LiteBus.Transport.Testing package and derive from TransportContractTests. The broker-neutral suite verifies payload and header round trips, explicit redelivery, and cancellation against the adapter's real broker.

Shared Observability Contract

Transport circuit breaker metrics are emitted on meter LiteBus.Transport and tagged by litebus.transport.broker.

Instrument	Public constant	Value semantics
`litebus.transport.circuit_breaker.open`	`LiteBusTransportTelemetry.CircuitBreakerOpenInstrumentName`	`1` when any publisher circuit is open or half-open; otherwise `0`
`litebus.transport.circuit_breaker.failure_count`	`LiteBusTransportTelemetry.CircuitBreakerFailureCountInstrumentName`	Sum of current failures across destination-scoped publisher circuits

Broker tag values in v6: amqp, kafka, sqs, azure_service_bus, inmemory.

Deep Docs

Topic	Location
Transport platform overview	Architecture.md
Package inventory and dependency roles	Dependency-Graph.md
AMQP transport guide	Amqp-Transport.md
Kafka transport guide	Kafka-Transport.md
AWS SQS transport guide	Aws-Sqs-Transport.md
Azure Service Bus transport guide	Azure-Service-Bus-Transport.md
Integration test executors	Integration-Tests.md

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