Ingress OpenTelemetry Metrics

ID: ingress.telemetry
Name: Ingress OpenTelemetry Metrics
Maturity: GA
Summary: Exposes stable ingress instrument names on the inbox meter for broker ack failures after successful accept.

Purpose and Scope

LiteBusInboxIngressTelemetry defines public instrument constants. TransportInboxIngressTelemetry increments ingress.ack_failed_after_accept when TransportMessage.AcceptAsync fails after the inbox store already accepted the delivery.

Register the inbox meter through AddLiteBusInboxMetrics() from LiteBus.Inbox.Extensions.OpenTelemetry (or axis-specific transport OpenTelemetry packages for transport-side metrics).

Public Surface

Constant / member	Value / role
`LiteBusInboxIngressTelemetry.MeterName`	`LiteBus.Inbox`
`LiteBusInboxIngressTelemetry.AckFailedAfterAcceptInstrumentName`	`ingress.ack_failed_after_accept`
`TransportInboxIngressTelemetry.RecordAckFailedAfterAccept()`	Internal recording site (consumer after accept-then-ack failure)
`MeterProviderBuilder.AddLiteBusInboxMetrics()`	Subscribes inbox meter including ingress counter
`TracerProviderBuilder.AddLiteBusTransportInstrumentation()`	Transport process activities from the consumer invoker

Instrument Contract

Public telemetry names here are treated as API contract. Renaming LiteBusInboxIngressTelemetry.MeterName or LiteBusInboxIngressTelemetry.AckFailedAfterAcceptInstrumentName is a breaking change for dashboards and alerts.

Packages

LiteBus.Inbox.Ingress (instrument constants and recording)
LiteBus.Inbox.Extensions.OpenTelemetry (meter registration)

Requires

OpenTelemetry host registration (hosting axis)
ingress.transport-consumer (recording site)

Invariants

Public instrument names are part of the consumer contract; renames are breaking changes.
Counter increments once per ack failure after accept, not per redelivery attempt at the store.
Counter recording is decoupled from requeue success, it records on ack failure before return-to-queue attempt.

Non-Goals

Distributed tracing activities dedicated to ingress (roadmap item; transport consume activities exist today).
Per-broker ingress dashboards in-box.
Health check mapping for ack failures (application-owned probes).

Observability

Ingress ships one public counter on the shared inbox meter. Transport process tracing is documented under the transport axis; the consumer invoker starts process {destination} spans.

Inbox Meter Instruments

Instrument	Type	Constant	When incremented	Recording site
`ingress.ack_failed_after_accept`	Counter	`LiteBusInboxIngressTelemetry.AckFailedAfterAcceptInstrumentName`	Broker `AcceptAsync` throws after `IInbox` accept succeeded	`TransportInboxIngressTelemetry.RecordAckFailedAfterAccept()` in `TransportInboxIngressConsumer`

Meter	Constant	Registration
`LiteBus.Inbox`	`LiteBusInboxIngressTelemetry.MeterName`	`MeterProviderBuilder.AddLiteBusInboxMetrics()`

After recording, the consumer logs EventId 3004 (AckFailedAfterAccept) and requeues so idempotent accept absorbs redelivery.

Broker Interpretation

Broker	Typical meaning of ack failure after accept
AMQP	Ack or channel operation failed after inbox row write
Kafka	Offset commit or acknowledgement path failed after inbox row write
AWS SQS	Delete or ack operation failed after inbox row write
Azure Service Bus	Complete or equivalent ack operation failed after inbox row write
InMemory	In-memory transport acknowledgement failed after inbox row write

Signal	Role
`process {destination}` activity	Per delivery in the consumer invoker; not an ingress meter
`litebus.transport.circuit_breaker.*`	Breaker state from the explicitly registered root transport

Registration Checklist

Install LiteBus.Inbox.Extensions.OpenTelemetry.
Call AddLiteBusInboxMetrics() on the meter provider builder.
For process spans, call AddLiteBusTransportInstrumentation().

Test Coverage

Covered

TransportInboxIngressConsumerTests.HandleDeliveryAsync_WhenAckFailsAfterAccept_ShouldNotDiscard attaches a MeterListener to LiteBus.Inbox, forces broker acknowledgement failure after a recorded inbox accept, and asserts that ingress.ack_failed_after_accept increments before the delivery is returned to the queue.

Untested

LiteBusInboxIngressTelemetry.MeterName registration through AddLiteBusInboxMetrics.
Counter semantics on duplicate redelivery attempts at the store.
Per-broker metric assertions in Kafka, AWS SQS, Azure Service Bus, and InMemory integration suites.

Out-of-Scope

Distributed tracing activities dedicated to ingress (transport consume activities exist today).
Per-broker ingress dashboards in-box.
Health check mapping for ack failures.