Support cursor based queries (#2501)

* Support cursor based queries

* Add unit test

* Start of a test case

* Update tests

* Mock out all connection stuff

* Run black

* Fix typo

* Use old python

* Run black on the tests

* Add changelog

* Fix sorting

* Use python 3.8 as baseline

---------

Co-authored-by: Diego Hurtado <ocelotl@users.noreply.github.com>

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2573](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2573))
 - `opentelemetry-instrumentation-confluent-kafka` Add support for version 2.4.0 of confluent_kafka
   ([#2616](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2616))
+- `opentelemetry-instrumentation-asyncpg` Add instrumentation to cursor based queries
+  ([#2501](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2501))
 - `opentelemetry-instrumentation-confluent-kafka` Add support for produce purge
   ([#2638](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2638))
 - `opentelemetry-instrumentation-httpx` Implement new semantic convention opt-in migration with stable http semantic conventions

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

@@ -127,15 +127,27 @@ class AsyncPGInstrumentor(BaseInstrumentor):
                 "asyncpg.connection", method, self._do_execute
             )
 
-    def _uninstrument(self, **__):
         for method in [
-            "execute",
-            "executemany",
-            "fetch",
-            "fetchval",
-            "fetchrow",
+            "Cursor.fetch",
+            "Cursor.forward",
+            "Cursor.fetchrow",
+            "CursorIterator.__anext__",
         ]:
-            unwrap(asyncpg.Connection, method)
+            wrapt.wrap_function_wrapper(
+                "asyncpg.cursor", method, self._do_cursor_execute
+            )
+
+    def _uninstrument(self, **__):
+        for cls, methods in [
+            (
+                asyncpg.connection.Connection,
+                ("execute", "executemany", "fetch", "fetchval", "fetchrow"),
+            ),
+            (asyncpg.cursor.Cursor, ("forward", "fetch", "fetchrow")),
+            (asyncpg.cursor.CursorIterator, ("__anext__",)),
+        ]:
+            for method_name in methods:
+                unwrap(cls, method_name)
 
     async def _do_execute(self, func, instance, args, kwargs):
         exception = None
@@ -170,3 +182,49 @@ class AsyncPGInstrumentor(BaseInstrumentor):
                     span.set_status(Status(StatusCode.ERROR))
 
         return result
+
+    async def _do_cursor_execute(self, func, instance, args, kwargs):
+        """Wrap cursor based functions. For every call this will generate a new span."""
+        exception = None
+        params = getattr(instance._connection, "_params", {})
+        name = (
+            instance._query
+            if instance._query
+            else params.get("database", "postgresql")
+        )
+
+        try:
+            # Strip leading comments so we get the operation name.
+            name = self._leading_comment_remover.sub("", name).split()[0]
+        except IndexError:
+            name = ""
+
+        stop = False
+        with self._tracer.start_as_current_span(
+            f"CURSOR: {name}",
+            kind=SpanKind.CLIENT,
+        ) as span:
+            if span.is_recording():
+                span_attributes = _hydrate_span_from_args(
+                    instance._connection,
+                    instance._query,
+                    instance._args if self.capture_parameters else None,
+                )
+                for attribute, value in span_attributes.items():
+                    span.set_attribute(attribute, value)
+
+            try:
+                result = await func(*args, **kwargs)
+            except StopAsyncIteration:
+                # Do not show this exception to the span
+                stop = True
+            except Exception as exc:  # pylint: disable=W0703
+                exception = exc
+                raise
+            finally:
+                if span.is_recording() and exception is not None:
+                    span.set_status(Status(StatusCode.ERROR))
+
+        if not stop:
+            return result
+        raise StopAsyncIteration

instrumentation/opentelemetry-instrumentation-asyncpg/tests/test_asyncpg_wrapper.py

@@ -1,4 +1,9 @@
-from asyncpg import Connection
+import asyncio
+from unittest import mock
+
+import pytest
+from asyncpg import Connection, Record, cursor
+from wrapt import ObjectProxy
 
 from opentelemetry.instrumentation.asyncpg import AsyncPGInstrumentor
 from opentelemetry.test.test_base import TestBase
@@ -34,3 +39,69 @@ class TestAsyncPGInstrumentation(TestBase):
             self.assertFalse(
                 hasattr(method, "_opentelemetry_ext_asyncpg_applied")
             )
+
+    def test_cursor_instrumentation(self):
+        def assert_wrapped(assert_fnc):
+            for cls, methods in [
+                (cursor.Cursor, ("forward", "fetch", "fetchrow")),
+                (cursor.CursorIterator, ("__anext__",)),
+            ]:
+                for method_name in methods:
+                    method = getattr(cls, method_name, None)
+                    assert_fnc(
+                        isinstance(method, ObjectProxy),
+                        f"{method} isinstance {type(method)}",
+                    )
+
+        assert_wrapped(self.assertFalse)
+        AsyncPGInstrumentor().instrument()
+        assert_wrapped(self.assertTrue)
+        AsyncPGInstrumentor().uninstrument()
+        assert_wrapped(self.assertFalse)
+
+    def test_cursor_span_creation(self):
+        """Test the cursor wrapper if it creates spans correctly."""
+
+        # Mock out all interaction with postgres
+        async def bind_mock(*args, **kwargs):
+            return []
+
+        async def exec_mock(*args, **kwargs):
+            return [], None, True
+
+        conn = mock.Mock()
+        conn.is_closed = lambda: False
+
+        conn._protocol = mock.Mock()
+        conn._protocol.bind = bind_mock
+        conn._protocol.execute = exec_mock
+        conn._protocol.bind_execute = exec_mock
+        conn._protocol.close_portal = bind_mock
+
+        state = mock.Mock()
+        state.closed = False
+
+        apg = AsyncPGInstrumentor()
+        apg.instrument(tracer_provider=self.tracer_provider)
+
+        # init the cursor and fetch a single record
+        crs = cursor.Cursor(conn, "SELECT * FROM test", state, [], Record)
+        asyncio.run(crs._init(1))
+        asyncio.run(crs.fetch(1))
+
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 1)
+        self.assertEqual(spans[0].name, "CURSOR: SELECT")
+        self.assertTrue(spans[0].status.is_ok)
+
+        # Now test that the StopAsyncIteration of the cursor does not get recorded as an ERROR
+        crs_iter = cursor.CursorIterator(
+            conn, "SELECT * FROM test", state, [], Record, 1, 1
+        )
+
+        with pytest.raises(StopAsyncIteration):
+            asyncio.run(crs_iter.__anext__())
+
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 2)
+        self.assertEqual([span.status.is_ok for span in spans], [True, True])