Repository: DataDog/dd-trace-py

Issue:
aioredis integration: Tracing breaks pipeline as context managers
Hello,

looks like the `aioredis` integration breaks the interface of `Pipeline` objects as context managers:

```py
RuntimeWarning: coroutine 'traced_pipeline' was never awaited
```

and

```py
async with redis.pipeline(transaction=True) as pipe:
AttributeError: __aexit__
```

This is bad since the documented of usage is exactly as context managers (see https://aioredis.readthedocs.io/en/latest/migration/#pipelines-and-transactions-multiexec).

The fix for now is to just use pipelines outside of contexts, without relying on them as context managers, but that is less than ideal.

`ddtrace` is the latest version (`0.57.0`).


Discussion:
@mklokocka thank you for reporting. I have been able to reproduce.

```python
# run.py
import asyncio

import aioredis


async def main():
    redis = await aioredis.from_url("redis://localhost")
    async with redis.pipeline(transaction=True) as pipe:
        ok1, ok2 = await (pipe.set("key1", "value1").set("key2", "value2").execute())
    assert ok1
    assert ok2


if __name__ == "__main__":
    asyncio.run(main())
```

```
$ ddtrace-run python run.py
```

Resolving patch:
diff --git a/ddtrace/contrib/aioredis/patch.py b/ddtrace/contrib/aioredis/patch.py
--- a/ddtrace/contrib/aioredis/patch.py
+++ b/ddtrace/contrib/aioredis/patch.py
@@ -70,8 +70,8 @@ async def traced_execute_command(func, instance, args, kwargs):
         return await func(*args, **kwargs)
 
 
-async def traced_pipeline(func, instance, args, kwargs):
-    pipeline = await func(*args, **kwargs)
+def traced_pipeline(func, instance, args, kwargs):
+    pipeline = func(*args, **kwargs)
     pin = Pin.get_from(instance)
     if pin:
         pin.onto(pipeline)


Test patch:
diff --git a/tests/contrib/aioredis/test_aioredis.py b/tests/contrib/aioredis/test_aioredis.py
--- a/tests/contrib/aioredis/test_aioredis.py
+++ b/tests/contrib/aioredis/test_aioredis.py
@@ -153,6 +153,35 @@ async def test_pipeline_traced(redis_client):
     assert response_list[3].decode() == "bar"
 
 
+@pytest.mark.skipif(aioredis_version < (2, 0), reason="only supported in aioredis >= 2.0")
+@pytest.mark.asyncio
+@pytest.mark.snapshot
+async def test_pipeline_traced_context_manager_transaction(redis_client):
+    """
+    Regression test for: https://github.com/DataDog/dd-trace-py/issues/3106
+
+    https://aioredis.readthedocs.io/en/latest/migration/#pipelines-and-transactions-multiexec
+
+    Example::
+
+        async def main():
+            redis = await aioredis.from_url("redis://localhost")
+            async with redis.pipeline(transaction=True) as pipe:
+                ok1, ok2 = await (pipe.set("key1", "value1").set("key2", "value2").execute())
+            assert ok1
+            assert ok2
+    """
+
+    async with redis_client.pipeline(transaction=True) as p:
+        set_1, set_2, get_1, get_2 = await (p.set("blah", "boo").set("foo", "bar").get("blah").get("foo").execute())
+
+    # response from redis.set is OK if successfully pushed
+    assert set_1 is True
+    assert set_2 is True
+    assert get_1.decode() == "boo"
+    assert get_2.decode() == "bar"
+
+
 @pytest.mark.asyncio
 @pytest.mark.snapshot(variants={"": aioredis_version >= (2, 0), "13": aioredis_version < (2, 0)})
 async def test_two_traced_pipelines(redis_client):
diff --git a/tests/snapshots/tests.contrib.aioredis.test_aioredis.test_pipeline_traced_context_manager_transaction.json b/tests/snapshots/tests.contrib.aioredis.test_aioredis.test_pipeline_traced_context_manager_transaction.json
new file mode 100644
--- /dev/null
+++ b/tests/snapshots/tests.contrib.aioredis.test_aioredis.test_pipeline_traced_context_manager_transaction.json
@@ -0,0 +1,28 @@
+[[
+  {
+    "name": "redis.command",
+    "service": "redis",
+    "resource": "SET blah boo\nSET foo bar\nGET blah\nGET foo",
+    "trace_id": 0,
+    "span_id": 1,
+    "parent_id": 0,
+    "type": "redis",
+    "meta": {
+      "out.host": "127.0.0.1",
+      "redis.raw_command": "SET blah boo\nSET foo bar\nGET blah\nGET foo",
+      "runtime-id": "b734eb991b1f45f2b063db6d3c5623b9"
+    },
+    "metrics": {
+      "_dd.agent_psr": 1.0,
+      "_dd.measured": 1,
+      "_dd.top_level": 1,
+      "_dd.tracer_kr": 1.0,
+      "_sampling_priority_v1": 1,
+      "out.port": 6379,
+      "out.redis_db": 0,
+      "redis.pipeline_length": 4,
+      "system.pid": 28312
+    },
+    "duration": 2132000,
+    "start": 1641496497488785000
+  }]]