From 77d5ee1aa7737d9491d3ac5c940b40de4882369e Mon Sep 17 00:00:00 2001
From: Erle Carrara <carrara.erle@gmail.com>
Date: Thu, 24 Oct 2024 17:07:20 -0300
Subject: [PATCH] Support functools.partial functions in
 AsyncioInstrumentor.trace_to_thread (#2911)

---
 CHANGELOG.md                                  |  3 ++
 .../instrumentation/asyncio/__init__.py       | 12 ++++---
 .../tests/test_asyncio_to_thread.py           | 35 +++++++++++++++++++
 3 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 028b4ee63e..0079547454 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -80,6 +80,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2753](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2753))
 - `opentelemetry-instrumentation-grpc` Fix grpc supported version
   ([#2845](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2845))
+- `opentelemetry-instrumentation-asyncio` fix `AttributeError` in
+  `AsyncioInstrumentor.trace_to_thread` when `func` is a `functools.partial` instance
+  ([#2911](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2911))
 
 ## Version 1.26.0/0.47b0 (2024-07-23)
 
diff --git a/instrumentation/opentelemetry-instrumentation-asyncio/src/opentelemetry/instrumentation/asyncio/__init__.py b/instrumentation/opentelemetry-instrumentation-asyncio/src/opentelemetry/instrumentation/asyncio/__init__.py
index a6cc6b044f..2d1b063dfd 100644
--- a/instrumentation/opentelemetry-instrumentation-asyncio/src/opentelemetry/instrumentation/asyncio/__init__.py
+++ b/instrumentation/opentelemetry-instrumentation-asyncio/src/opentelemetry/instrumentation/asyncio/__init__.py
@@ -78,6 +78,7 @@ def func():
 """
 
 import asyncio
+import functools
 import sys
 from asyncio import futures
 from timeit import default_timer
@@ -231,14 +232,15 @@ def wrap_taskgroup_create_task(method, instance, args, kwargs) -> None:
     def trace_to_thread(self, func: callable):
         """Trace a function."""
         start = default_timer()
+        func_name = getattr(func, "__name__", None)
+        if func_name is None and isinstance(func, functools.partial):
+            func_name = func.func.__name__
         span = (
-            self._tracer.start_span(
-                f"{ASYNCIO_PREFIX} to_thread-" + func.__name__
-            )
-            if func.__name__ in self._to_thread_name_to_trace
+            self._tracer.start_span(f"{ASYNCIO_PREFIX} to_thread-" + func_name)
+            if func_name in self._to_thread_name_to_trace
             else None
         )
-        attr = {"type": "to_thread", "name": func.__name__}
+        attr = {"type": "to_thread", "name": func_name}
         exception = None
         try:
             attr["state"] = "finished"
diff --git a/instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_to_thread.py b/instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_to_thread.py
index 3d795d8ae7..35191d3d03 100644
--- a/instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_to_thread.py
+++ b/instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_to_thread.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import asyncio
+import functools
 import sys
 from unittest import skipIf
 from unittest.mock import patch
@@ -72,3 +73,37 @@ async def to_thread():
                 for point in metric.data.data_points:
                     self.assertEqual(point.attributes["type"], "to_thread")
                     self.assertEqual(point.attributes["name"], "multiply")
+
+    @skipIf(
+        sys.version_info < (3, 9), "to_thread is only available in Python 3.9+"
+    )
+    def test_to_thread_partial_func(self):
+        def multiply(x, y):
+            return x * y
+
+        double = functools.partial(multiply, 2)
+
+        async def to_thread():
+            result = await asyncio.to_thread(double, 3)
+            assert result == 6
+
+        with self._tracer.start_as_current_span("root"):
+            asyncio.run(to_thread())
+        spans = self.memory_exporter.get_finished_spans()
+
+        self.assertEqual(len(spans), 2)
+        assert spans[0].name == "asyncio to_thread-multiply"
+        for metric in (
+            self.memory_metrics_reader.get_metrics_data()
+            .resource_metrics[0]
+            .scope_metrics[0]
+            .metrics
+        ):
+            if metric.name == "asyncio.process.duration":
+                for point in metric.data.data_points:
+                    self.assertEqual(point.attributes["type"], "to_thread")
+                    self.assertEqual(point.attributes["name"], "multiply")
+            if metric.name == "asyncio.process.created":
+                for point in metric.data.data_points:
+                    self.assertEqual(point.attributes["type"], "to_thread")
+                    self.assertEqual(point.attributes["name"], "multiply")