httpx: add the is_instrumented flag to the transport

CHANGELOG.md

@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- `opentelemetry-instrumentation-httpx` Instrument transport instead of HTTPX client
+ ([#3106](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3106))
+
 ## Version 1.29.0/0.50b0 (2024-12-11)
 
 ### Added

instrumentation/opentelemetry-instrumentation-httpx/src/opentelemetry/instrumentation/httpx/__init__.py

@@ -402,6 +402,8 @@ class SyncOpenTelemetryTransport(httpx.BaseTransport):
  that is called right before the span ends
  """
 
+ _is_instrumented_by_opentelemetry = True
+
  def __init__(
  self,
  transport: httpx.BaseTransport,
@@ -527,6 +529,8 @@ class AsyncOpenTelemetryTransport(httpx.AsyncBaseTransport):
  that is called right before the span ends
  """
 
+ _is_instrumented_by_opentelemetry = True
+
  def __init__(
  self,
  transport: httpx.AsyncBaseTransport,
@@ -895,6 +899,10 @@ def instrument_client(
  "Attempting to instrument Httpx client while already instrumented"
  )
  return
+ if getattr(
+ client._transport, "is_instrumented_by_opentelemetry", False
+ ):
+ return
 
  _OpenTelemetrySemanticConventionStability._initialize()
  sem_conv_opt_in_mode = _OpenTelemetrySemanticConventionStability._get_opentelemetry_stability_opt_in_mode(
@@ -946,6 +954,7 @@ def instrument_client(
  response_hook=response_hook,
  ),
  )
+ client._transport._is_instrumented_by_opentelemetry = True
  client._is_instrumented_by_opentelemetry = True
  if hasattr(client._transport, "handle_async_request"):
  wrap_function_wrapper(
@@ -972,6 +981,7 @@ def instrument_client(
  async_response_hook=async_response_hook,
  ),
  )
+ client._transport._is_instrumented_by_opentelemetry = True
  client._is_instrumented_by_opentelemetry = True
 
  @staticmethod
@@ -987,9 +997,11 @@ def uninstrument_client(
  unwrap(client._transport, "handle_request")
  for transport in client._mounts.values():
  unwrap(transport, "handle_request")
+ client._transport._is_instrumented_by_opentelemetry = False
  client._is_instrumented_by_opentelemetry = False
  elif hasattr(client._transport, "handle_async_request"):
  unwrap(client._transport, "handle_async_request")
  for transport in client._mounts.values():
  unwrap(transport, "handle_async_request")
+ client._transport._is_instrumented_by_opentelemetry = False
  client._is_instrumented_by_opentelemetry = False

instrumentation/opentelemetry-instrumentation-httpx/tests/test_httpx_integration.py

@@ -14,6 +14,8 @@
 
 # pylint: disable=too-many-lines
 
+from __future__ import annotations
+
 import abc
 import asyncio
 import typing
@@ -593,10 +595,10 @@ def create_transport(
  @abc.abstractmethod
  def create_client(
  self,
- transport: typing.Union[
-  SyncOpenTelemetryTransport, AsyncOpenTelemetryTransport, None
- ] = None,
- **kwargs,
+ transport: SyncOpenTelemetryTransport
+ | AsyncOpenTelemetryTransport
+ | None = None,
+ **kwargs: typing.Any,
  ):
  pass
 
@@ -730,9 +732,9 @@ class BaseInstrumentorTest(BaseTest, metaclass=abc.ABCMeta):
  @abc.abstractmethod
  def create_client(
  self,
- transport: typing.Union[
-  SyncOpenTelemetryTransport, AsyncOpenTelemetryTransport, None
- ] = None,
+ transport: SyncOpenTelemetryTransport
+ | AsyncOpenTelemetryTransport
+ | None = None,
  **kwargs,
  ):
  pass
@@ -926,6 +928,17 @@ def test_instrument_client_called_on_the_class(self):
  self.assertEqual(result.text, "Hello!")
  self.assert_span(num_spans=1)
 
+ def test_instrument_multiple_clients_with_the_same_transport(self):
+ client1 = self.create_client()
+ client2 = self.create_client(transport=client1._transport)
+
+ HTTPXClientInstrumentor().instrument_client(client1)
+ HTTPXClientInstrumentor().instrument_client(client2)
+
+ result = self.perform_request(self.URL, client=client1)
+ self.assertEqual(result.text, "Hello!")
+ self.assert_span(num_spans=1)
+
  def test_instrumentation_without_client(self):
  HTTPXClientInstrumentor().instrument()
  results = [
@@ -1210,7 +1223,7 @@ def create_client(
  transport: typing.Optional[SyncOpenTelemetryTransport] = None,
  **kwargs,
  ):
- return httpx.Client(**kwargs)
+ return httpx.Client(transport=transport, **kwargs)
 
  def perform_request(
  self,
@@ -1260,7 +1273,7 @@ def create_client(
  transport: typing.Optional[AsyncOpenTelemetryTransport] = None,
  **kwargs,
  ):
- return httpx.AsyncClient(**kwargs)
+ return httpx.AsyncClient(transport=transport, **kwargs)
 
  def perform_request(
  self,