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feat(eventhubs): add tracing and AMQP lifecycle observability - #7368

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feat(eventhubs): add tracing and AMQP lifecycle observability#7368
Johnathan W (j7nw4r) wants to merge 18 commits into
Azure:mainfrom
j7nw4r:feat/7336-eventhubs-observability

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@j7nw4r Johnathan W (j7nw4r) commented Aug 21, 2026

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Summary

  • Adds provider-neutral distributed tracing for Event Hubs send and receive operations.
  • Adds AMQP child spans for link attachment, send disposition, and blocking receive latency.
  • Adds structured lifecycle records that identify connection, session, and link failures and distinguish recreated instances by generation.
  • Improves uAMQP failure records with connection and link identifiers.
  • Fixes the single-message batch-count and receive source-name tracing attributes.

Direct metrics are not emitted because Azure Core does not expose a provider-neutral meter API. Failure counters and latency histograms can be derived from the lifecycle records and span durations.

Supersedes #7339.
Fixes #7336.

Verification

  • A live Azure smoke test using AzureCliCredential successfully sent and received an event through an existing Event Hub.
  • The OpenTelemetry ostream exporter produced the expected operation and AMQP child spans with correct parent/child relationships and component identifiers.
  • The live run emitted 17 connection, session, and link lifecycle records.
  • The initial live run exposed a non-owning string lifetime bug in az.eventhubs.amqp.component.id; the bug was fixed and the live test passed on rerun.
  • Live connection disruption and recreation were not forced. Failure and recreation paths are covered by the focused unit tests.
  • Rust AMQP Event Hubs test target builds.
  • uAMQP Event Hubs test target builds.
  • EventHubsTracingTest.*: 22/22 passed on Rust AMQP.
  • EventHubsTracingTest.*: 22/22 passed on uAMQP.
  • clang-format-11 and git diff --check pass.

Checklist

  • Tests added or updated.
  • Public API changes documented.
  • Changelog updated.
  • Formatting checks pass.

Add eventhubs_tracing_test.cpp with the recording tracer, span, and
attribute set doubles for the Event Hubs tracing work in issue 7336.

The tests pin the TracingProvider option on ProducerClientOptions and
ConsumerClientOptions, the eager tracer creation in both clients, the
ProducerClient.Send span shape on a cancelled context and on a
non-cancel exception, and the shape of the shared StartSpan helper for
PartitionClient.ReceiveEvents.

Tests 1 to 7 do not compile until the tracing source lands. The
TracingProvider member does not exist yet, and the private header
src/private/eventhubs_tracing.hpp does not exist yet.

SendWithoutProviderIsUnchanged is a characterization test. It passes
today. It guards the no-provider path against a null dereference after
the source lands.
ProducerClientOptions and ConsumerClientOptions gain a TracingProvider
field. Each client builds a TracingContextFactory from that field at
construction time. When the field is empty, the factory has no tracer
and the clients create no spans.

ProducerClient::Send creates one Producer span named
ProducerClient.Send. PartitionClient::ReceiveEvents creates one Client
span named PartitionClient.ReceiveEvents. Both spans carry the
messaging attributes, the az.namespace attribute, and the message
count. Both spans record an exception event and an error status, then
rethrow the original exception.

A new private helper, src/private/eventhubs_tracing.hpp, holds the
factory creation and the span shape, so the producer and the partition
client emit the same attributes.

EventDataBatch::NumberOfEvents is now const, and its mutex is mutable,
because Send takes the batch by const reference.

Trace-context propagation and span links stay deferred, because Azure
Core has no API for them.
Run clang-format-11 over eventhubs_tracing_test.cpp. The declarations
of AddAttributes and SetStatus on the recording span double broke the
Validate Clang Format step in CI.

The change is formatting only. No assertion, no test name, and no
behavior changed.
ProducerClient::Send converted the batch to an AMQP message before it
started the span. An empty batch makes that conversion throw, so the
send failed before a span existed and nothing recorded the failure.

The conversion now runs at the top of the try block, after the span
starts. The existing catch clause adds the exception to the span and
rethrows, the same as every other send failure.
The OpenTelemetry semantic conventions at schema 1.17.0 define
messaging.batch.message_count as an int. The Event Hubs tracing helper
records it as a string, and the test doubles could not show the
difference, because they stringified every overload into one map.

TestAttributeSet and TestSpan now record a type tag for each attribute.
The tag names the overload that delivered the value. Three tests use it:
the receive span count and the send span count must arrive through the
uint64 overload, and SetMessageCount must stay quiet and safe when the
factory has no tracer. The first two tests are red today. The third one
is a characterization test that guards the null attribute set hazard.
The batch message count now goes out as an unsigned integer attribute,
which matches the OpenTelemetry semantic conventions at schema 1.17.0.
Before this change the helper wrote the count as a string.

SetMessageCount takes the tracing context factory, because the typed
attribute needs an attribute set. The helper guards the null attribute
set on the no-tracer path, because the factory returns nullptr when it
has no tracer and that pointer is not null safe.
The span helper built a std::string temporary for each attribute name
before it added the attribute. Two of the names are longer than the
libc++ small-string limit, so each call heap allocated even when the
client had no tracer and dropped every attribute.

The span helper now returns the tracing context immediately when the
factory has no tracer. The message count helper keeps its own null
attribute set guard, because PartitionClient::ReceiveEvents calls it
directly.

The remaining two allocations per operation come from azure-core and
are tracked in issue 7340.
The SingleSpan helper called front() on the tracer list after a
non-fatal EXPECT_EQ on the list size. When no tracer was created, that
call dereferenced an empty std::list and the test process ended in a
segmentation fault. The crash stopped the run, so the tests after the
first affected one never reported at all.

The helper now returns null when the tracer list is not the expected
size, so a failure reports through the caller's ASSERT_NE assertion
rather than a crash. This mirrors the guard that already protects the
spans list two lines later.
The receive span of PartitionClient::ReceiveEvents has no offline
coverage. A partition client comes only from a factory that opens a
live AMQP link, so no unit test can reach the span, the message count,
or the exception path.

This test runs against a real namespace. It gives the consumer client
a recording tracing provider, receives events from a partition, and
makes sure the span name, the span kind, the messaging attributes, and
the message count are correct. The count assertion compares the span
attribute with the size of the vector that ReceiveEvents returned.

The recording tracing test doubles move from eventhubs_tracing_test.cpp
into a shared header, because the live test lives in a different file.
The two convenience Send overloads build the batch before they send it,
and CreateBatch opens the connection, the session and the AMQP link. A
bad host fails there. Only the batch overload starts a span today, so
that failure unwinds with no span at all.

Add two offline tests that send one event and a vector of three events
against a fake connection string. Each test asserts one span named
ProducerClient.Send with the kind Producer, the message count as a
uint64 attribute, one recorded event and the Error status. Both fail
today because the provider holds zero spans.

Add a characterization test that keeps the no-provider path unchanged,
and a live test that sends one event and asserts a single span. The
live test catches a nested second span, which an offline test cannot
reach because CreateBatch always throws offline.
The convenience Send overloads made the batch first, and the batch
creation opens the connection, the session, and the AMQP link. A bad
host or a failed authentication threw there, and the stack unwound
before a span existed. A caller then saw no producer span for the
failed send.

Each public Send overload now starts one span, and one try/catch
records the exception on that span. A new private method,
SendBatchInSpan, holds the send body and starts no span, so one
logical send still makes one span. The convenience overloads pass the
span context to CreateBatch, which puts the link open under the span.
The tracing change added a TracingProvider field to
ProducerClientOptions and ConsumerClientOptions, but no document told
a user how to set it. The only repo document on tracing,
doc/DistributedTracing.md, showed clientOptions.Telemetry.TracingProvider.
That line does not compile for Event Hubs, because the two option
structs do not derive from Azure::Core::_internal::ClientOptions and
have no Telemetry field.

- Adds a "Distributed tracing" section to the Event Hubs README with a
  snippet that builds an OpenTelemetryProvider and sets TracingProvider
  on both client options.
- Lists the span names, the span kinds, and the attributes that the
  clients emit, and names the 1.17.0 semantic conventions schema.
- States that the client creates no spans when TracingProvider is not
  set, because there is no global fallback provider.
- Adds a note to doc/DistributedTracing.md for the clients that declare
  TracingProvider at the top level of their own options structure.
Identify Event Hubs AMQP connections, sessions, and links in lifecycle logs and record their failures, teardown, and recreation generations. Attribute scoped AMQP conditions to the failed protocol layer.

Add child spans around link attachment, send disposition, and blocking receive calls so exporters can separate caller-visible SDK latency from AMQP transport latency. Document how to derive failure counters and latency histograms from logs and spans.

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Pull request overview

Adds provider-neutral Event Hubs tracing and structured AMQP lifecycle observability.

Changes:

  • Adds send, receive, and AMQP transport spans.
  • Adds component identifiers, generations, and failure logs.
  • Adds tracing tests and documentation.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 4 comments.

Show a summary per file
File Description
sdk/eventhubs/azure-messaging-eventhubs/test/ut/producer_client_test.cpp Tests live send tracing.
sdk/eventhubs/azure-messaging-eventhubs/test/ut/eventhubs_tracing_test.cpp Tests tracing and lifecycle records.
sdk/eventhubs/azure-messaging-eventhubs/test/ut/eventhubs_tracing_test_doubles.hpp Adds tracing test doubles.
sdk/eventhubs/azure-messaging-eventhubs/test/ut/consumer_client_test.cpp Tests live receive tracing.
sdk/eventhubs/azure-messaging-eventhubs/test/ut/CMakeLists.txt Registers tracing tests.
sdk/eventhubs/azure-messaging-eventhubs/src/producer_client.cpp Instruments sends and producer lifecycle.
sdk/eventhubs/azure-messaging-eventhubs/src/private/eventhubs_utilities.hpp Extends partition factory inputs.
sdk/eventhubs/azure-messaging-eventhubs/src/private/eventhubs_tracing.hpp Declares tracing helpers.
sdk/eventhubs/azure-messaging-eventhubs/src/private/eventhubs_diagnostics.hpp Declares lifecycle helpers.
sdk/eventhubs/azure-messaging-eventhubs/src/partition_client.cpp Instruments receives and receiver lifecycle.
sdk/eventhubs/azure-messaging-eventhubs/src/eventhubs_tracing.cpp Implements span creation and attributes.
sdk/eventhubs/azure-messaging-eventhubs/src/eventhubs_diagnostics.cpp Implements structured lifecycle records.
sdk/eventhubs/azure-messaging-eventhubs/src/consumer_client.cpp Propagates tracing and diagnostics state.
sdk/eventhubs/azure-messaging-eventhubs/README.md Documents tracing and lifecycle logs.
sdk/eventhubs/azure-messaging-eventhubs/inc/azure/messaging/eventhubs/producer_client.hpp Exposes producer tracing configuration.
sdk/eventhubs/azure-messaging-eventhubs/inc/azure/messaging/eventhubs/partition_client.hpp Stores partition tracing metadata.
sdk/eventhubs/azure-messaging-eventhubs/inc/azure/messaging/eventhubs/event_data_batch.hpp Makes event count const-accessible.
sdk/eventhubs/azure-messaging-eventhubs/inc/azure/messaging/eventhubs/consumer_client.hpp Exposes consumer tracing configuration.
sdk/eventhubs/azure-messaging-eventhubs/CMakeLists.txt Builds diagnostics and tracing sources.
sdk/eventhubs/azure-messaging-eventhubs/CHANGELOG.md Records Event Hubs observability changes.
sdk/core/azure-core-amqp/src/impl/uamqp/amqp/message_sender.cpp Improves sender failure logs.
sdk/core/azure-core-amqp/src/impl/uamqp/amqp/message_receiver.cpp Improves receiver failure logs.
sdk/core/azure-core-amqp/src/impl/uamqp/amqp/connection.cpp Improves connection failure logs.
sdk/core/azure-core-amqp/CHANGELOG.md Records uAMQP logging changes.
doc/DistributedTracing.md Documents top-level tracing options.

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Comment thread sdk/eventhubs/azure-messaging-eventhubs/src/partition_client.cpp
Comment thread sdk/eventhubs/azure-messaging-eventhubs/src/producer_client.cpp Outdated
Comment thread sdk/eventhubs/azure-messaging-eventhubs/README.md Outdated
Comment thread sdk/eventhubs/azure-messaging-eventhubs/README.md Outdated
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Add distributed tracing instrumentation to the Event Hubs SDK

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