genai-util: refactor streams to a generic ABC wrapper.

AGENTS.md

@@ -76,6 +76,11 @@ Apply to packages under `instrumentation/` and `instrumentation-genai/`.
 - When catching exceptions from the underlying library to record telemetry, always re-raise the
   original exception unmodified.
 - Do not raise new exceptions in instrumentation/telemetry code.
+- For GenAI streaming wrappers, prefer the shared `SyncStreamWrapper` and `AsyncStreamWrapper`
+  helpers from `opentelemetry.util.genai.stream` instead of reimplementing iteration,
+  close/context-manager, and finalization behavior in provider packages.
+- Put provider-specific chunk parsing and telemetry finalization in private hook methods or a
+  narrow mixin. Do not make async stream wrappers inherit from sync stream wrappers.
 
 ### Semantic conventions
 

CLAUDE.md

@@ -1 +1,2 @@
 @AGENTS.md
+

instrumentation-genai/opentelemetry-instrumentation-openai-v2/CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Refactor chat completion stream wrappers to use shared GenAI stream lifecycle helpers.
+  ([#4500](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4500))
 ## Version 2.4b0 (2026-05-01)
 
 

instrumentation-genai/opentelemetry-instrumentation-openai-v2/src/opentelemetry/instrumentation/openai_v2/chat_buffers.py

@@ -0,0 +1,52 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class ToolCallBuffer:
+    def __init__(self, index, tool_call_id, function_name):
+        self.index = index
+        self.function_name = function_name
+        self.tool_call_id = tool_call_id
+        self.arguments = []
+
+    def append_arguments(self, arguments):
+        if arguments is not None:
+            self.arguments.append(arguments)
+
+
+class ChoiceBuffer:
+    def __init__(self, index):
+        self.index = index
+        self.finish_reason = None
+        self.text_content = []
+        self.tool_calls_buffers = []
+
+    def append_text_content(self, content):
+        self.text_content.append(content)
+
+    def append_tool_call(self, tool_call):
+        idx = tool_call.index
+        for _ in range(len(self.tool_calls_buffers), idx + 1):
+            self.tool_calls_buffers.append(None)
+
+        function = tool_call.function
+        if not self.tool_calls_buffers[idx]:
+            self.tool_calls_buffers[idx] = ToolCallBuffer(
+                idx,
+                tool_call.id,
+                function.name if function else None,
+            )
+
+        if function:
+            self.tool_calls_buffers[idx].append_arguments(function.arguments)

instrumentation-genai/opentelemetry-instrumentation-openai-v2/src/opentelemetry/instrumentation/openai_v2/chat_wrappers.py

@@ -0,0 +1,219 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import json
+from typing import Any, Optional
+
+from openai import AsyncStream, Stream
+
+from opentelemetry.semconv._incubating.attributes import (
+    openai_attributes as OpenAIAttributes,
+)
+from opentelemetry.util.genai.invocation import InferenceInvocation
+from opentelemetry.util.genai.stream import (
+    AsyncStreamWrapper,
+    SyncStreamWrapper,
+)
+from opentelemetry.util.genai.types import (
+    OutputMessage,
+    Text,
+    ToolCallRequest,
+)
+
+from .chat_buffers import ChoiceBuffer
+
+
+class _ChatStreamMixin:
+    """Chat-specific hooks shared by sync and async stream wrappers."""
+
+    invocation: InferenceInvocation
+    capture_content: bool
+    choice_buffers: list
+    response_id: Optional[str] = None
+    response_model: Optional[str] = None
+    service_tier: Optional[str] = None
+    prompt_tokens: Optional[int] = None
+    completion_tokens: Optional[int] = None
+
+    def _set_response_model(self, chunk):
+        if self.response_model:
+            return
+
+        if getattr(chunk, "model", None):
+            self.response_model = chunk.model
+
+    def _set_response_id(self, chunk):
+        if self.response_id:
+            return
+
+        if getattr(chunk, "id", None):
+            self.response_id = chunk.id
+
+    def _set_response_service_tier(self, chunk):
+        if self.service_tier:
+            return
+
+        if getattr(chunk, "service_tier", None):
+            self.service_tier = chunk.service_tier
+
+    def _build_streaming_response(self, chunk):
+        if getattr(chunk, "choices", None) is None:
+            return
+
+        choices = chunk.choices
+        for choice in choices:
+            if not choice.delta:
+                continue
+
+            for idx in range(len(self.choice_buffers), choice.index + 1):
+                self.choice_buffers.append(ChoiceBuffer(idx))
+
+            if choice.finish_reason:
+                self.choice_buffers[
+                    choice.index
+                ].finish_reason = choice.finish_reason
+
+            if choice.delta.content is not None:
+                self.choice_buffers[choice.index].append_text_content(
+                    choice.delta.content
+                )
+
+            if choice.delta.tool_calls is not None:
+                for tool_call in choice.delta.tool_calls:
+                    self.choice_buffers[choice.index].append_tool_call(
+                        tool_call
+                    )
+
+    def _set_usage(self, chunk):
+        if getattr(chunk, "usage", None):
+            self.completion_tokens = chunk.usage.completion_tokens
+            self.prompt_tokens = chunk.usage.prompt_tokens
+
+    def _process_chunk(self, chunk):
+        self._set_response_id(chunk)
+        self._set_response_model(chunk)
+        self._set_response_service_tier(chunk)
+        self._build_streaming_response(chunk)
+        self._set_usage(chunk)
+
+    def _set_output_messages(self):
+        if not self.capture_content:  # optimization
+            return
+        output_messages = []
+        for choice in self.choice_buffers:
+            message = OutputMessage(
+                role="assistant",
+                finish_reason=choice.finish_reason or "error",
+                parts=[],
+            )
+            if choice.text_content:
+                message.parts.append(
+                    Text(content="".join(choice.text_content))
+                )
+            if choice.tool_calls_buffers:
+                tool_calls = []
+                for tool_call in choice.tool_calls_buffers:
+                    arguments = None
+                    arguments_str = "".join(tool_call.arguments)
+                    if arguments_str:
+                        try:
+                            arguments = json.loads(arguments_str)
+                        except json.JSONDecodeError:
+                            arguments = arguments_str
+                    tool_call_part = ToolCallRequest(
+                        name=tool_call.function_name,
+                        id=tool_call.tool_call_id,
+                        arguments=arguments,
+                    )
+                    tool_calls.append(tool_call_part)
+                message.parts.extend(tool_calls)
+            output_messages.append(message)
+
+        self.invocation.output_messages = output_messages
+
+    def _stop_stream(self) -> None:
+        self._cleanup()
+
+    def _fail_stream(self, error: BaseException) -> None:
+        self._cleanup(error)
+
+    def parse(self):
+        """Called when using with_raw_response with stream=True."""
+        return self
+
+    def _cleanup(self, error: Optional[BaseException] = None) -> None:
+        self.invocation.response_model_name = self.response_model
+        self.invocation.response_id = self.response_id
+        self.invocation.input_tokens = self.prompt_tokens
+        self.invocation.output_tokens = self.completion_tokens
+        finish_reasons = [
+            choice.finish_reason
+            for choice in self.choice_buffers
+            if choice.finish_reason
+        ]
+        if finish_reasons:
+            self.invocation.finish_reasons = finish_reasons
+        if self.service_tier:
+            self.invocation.attributes.update(
+                {
+                    OpenAIAttributes.OPENAI_RESPONSE_SERVICE_TIER: self.service_tier
+                },
+            )
+
+        self._set_output_messages()
+
+        if error:
+            self.invocation.fail(error)
+        else:
+            self.invocation.stop()
+
+
+class ChatStreamWrapper(
+    _ChatStreamMixin,
+    SyncStreamWrapper[Any],
+):
+    def __init__(
+        self,
+        stream: Stream,
+        invocation: InferenceInvocation,
+        capture_content: bool,
+    ):
+        super().__init__(stream)
+        self.invocation = invocation
+        self.choice_buffers = []
+        self.capture_content = capture_content
+
+
+class AsyncChatStreamWrapper(
+    _ChatStreamMixin,
+    AsyncStreamWrapper[Any],
+):
+    def __init__(
+        self,
+        stream: AsyncStream,
+        invocation: InferenceInvocation,
+        capture_content: bool,
+    ):
+        super().__init__(stream)
+        self.invocation = invocation
+        self.choice_buffers = []
+        self.capture_content = capture_content
+
+
+__all__ = [
+    "AsyncChatStreamWrapper",
+    "ChatStreamWrapper",
+]