Adding multiple db connections support for django-instrumentation's sqlcommenter (#1187)

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.12.0rc2-0.32b0...HEAD)
+- Adding multiple db connections support for django-instrumentation's sqlcommenter
+  ([#1187](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1187))
 
 ### Added
 - `opentelemetry-instrumentation-redis` add support to instrument RedisCluster clients

instrumentation/opentelemetry-instrumentation-django/src/opentelemetry/instrumentation/django/middleware/sqlcommenter_middleware.py

@@ -13,15 +13,19 @@
 # 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 contextlib import ExitStack
 from logging import getLogger
 from typing import Any, Type, TypeVar
-from urllib.parse import quote as urllib_quote
 
 # pylint: disable=no-name-in-module
 from django import conf, get_version
-from django.db import connection
+from django.db import connections
 from django.db.backends.utils import CursorDebugWrapper
 
+from opentelemetry.instrumentation.utils import (
+    _generate_sql_comment,
+    _get_opentelemetry_values,
+)
 from opentelemetry.trace.propagation.tracecontext import (
     TraceContextTextMapPropagator,
 )
@@ -44,7 +48,13 @@ class SqlCommenter:
         self.get_response = get_response
 
     def __call__(self, request) -> Any:
-        with connection.execute_wrapper(_QueryWrapper(request)):
+        with ExitStack() as stack:
+            for db_alias in connections:
+                stack.enter_context(
+                    connections[db_alias].execute_wrapper(
+                        _QueryWrapper(request)
+                    )
+                )
             return self.get_response(request)
 
 
@@ -105,49 +115,7 @@ class _QueryWrapper:
         sql += sql_comment
 
         # Add the query to the query log if debugging.
-        if context["cursor"].__class__ is CursorDebugWrapper:
+        if isinstance(context["cursor"], CursorDebugWrapper):
             context["connection"].queries_log.append(sql)
 
         return execute(sql, params, many, context)
-
-
-def _generate_sql_comment(**meta) -> str:
-    """
-    Return a SQL comment with comma delimited key=value pairs created from
-    **meta kwargs.
-    """
-    key_value_delimiter = ","
-
-    if not meta:  # No entries added.
-        return ""
-
-    # Sort the keywords to ensure that caching works and that testing is
-    # deterministic. It eases visual inspection as well.
-    return (
-        " /*"
-        + key_value_delimiter.join(
-            f"{_url_quote(key)}={_url_quote(value)!r}"
-            for key, value in sorted(meta.items())
-            if value is not None
-        )
-        + "*/"
-    )
-
-
-def _url_quote(value) -> str:
-    if not isinstance(value, (str, bytes)):
-        return value
-    _quoted = urllib_quote(value)
-    # Since SQL uses '%' as a keyword, '%' is a by-product of url quoting
-    # e.g. foo,bar --> foo%2Cbar
-    # thus in our quoting, we need to escape it too to finally give
-    #      foo,bar --> foo%%2Cbar
-    return _quoted.replace("%", "%%")
-
-
-def _get_opentelemetry_values() -> dict or None:
-    """
-    Return the OpenTelemetry Trace and Span IDs if Span ID is set in the
-    OpenTelemetry execution context.
-    """
-    return _propagator.inject({})

instrumentation/opentelemetry-instrumentation-django/tests/test_middleware.py

@@ -86,7 +86,13 @@ _django_instrumentor = DjangoInstrumentor()
 class TestMiddleware(WsgiTestBase):
     @classmethod
     def setUpClass(cls):
-        conf.settings.configure(ROOT_URLCONF=modules[__name__])
+        conf.settings.configure(
+            ROOT_URLCONF=modules[__name__],
+            DATABASES={
+                "default": {},
+                "other": {},
+            },  # db.connections gets populated only at first test execution
+        )
         super().setUpClass()
 
     def setUp(self):

instrumentation/opentelemetry-instrumentation-django/tests/test_sqlcommenter.py

@@ -13,15 +13,16 @@
 # limitations under the License.
 
 # pylint: disable=no-name-in-module
-
 from unittest.mock import MagicMock, patch
 
+import pytest
 from django import VERSION, conf
 from django.http import HttpResponse
 from django.test.utils import setup_test_environment, teardown_test_environment
 
 from opentelemetry.instrumentation.django import DjangoInstrumentor
 from opentelemetry.instrumentation.django.middleware.sqlcommenter_middleware import (
+    SqlCommenter,
     _QueryWrapper,
 )
 from opentelemetry.test.wsgitestutil import WsgiTestBase
@@ -98,3 +99,19 @@ class TestMiddleware(WsgiTestBase):
             "Select 1 /*app_name='app',controller='view',route='route',traceparent='%%2Atraceparent%%3D%%2700-0000000"
             "00000000000000000deadbeef-000000000000beef-00'*/",
         )
+
+    @patch(
+        "opentelemetry.instrumentation.django.middleware.sqlcommenter_middleware._QueryWrapper"
+    )
+    def test_multiple_connection_support(self, query_wrapper):
+        if not DJANGO_2_0:
+            pytest.skip()
+
+        requests_mock = MagicMock()
+        get_response = MagicMock()
+
+        sql_instance = SqlCommenter(get_response)
+        sql_instance(requests_mock)
+
+        # check if query_wrapper is added to the context for 2 databases
+        self.assertEqual(query_wrapper.call_count, 2)

opentelemetry-instrumentation/src/opentelemetry/instrumentation/utils.py

@@ -25,6 +25,11 @@ from opentelemetry import context, trace
 from opentelemetry.context import _SUPPRESS_INSTRUMENTATION_KEY  # noqa: F401
 from opentelemetry.propagate import extract
 from opentelemetry.trace import Span, StatusCode
+from opentelemetry.trace.propagation.tracecontext import (
+    TraceContextTextMapPropagator,
+)
+
+propagator = TraceContextTextMapPropagator()
 
 
 def extract_attributes_from_object(
@@ -119,24 +124,22 @@ def _start_internal_or_server_span(
     return span, token
 
 
-_KEY_VALUE_DELIMITER = ","
-
-
-def _generate_sql_comment(**meta):
+def _generate_sql_comment(**meta) -> str:
     """
     Return a SQL comment with comma delimited key=value pairs created from
     **meta kwargs.
     """
+    key_value_delimiter = ","
+
     if not meta:  # No entries added.
         return ""
 
     # Sort the keywords to ensure that caching works and that testing is
     # deterministic. It eases visual inspection as well.
-    # pylint: disable=consider-using-f-string
     return (
         " /*"
-        + _KEY_VALUE_DELIMITER.join(
-            "{}={!r}".format(_url_quote(key), _url_quote(value))
+        + key_value_delimiter.join(
+            f"{_url_quote(key)}={_url_quote(value)!r}"
             for key, value in sorted(meta.items())
             if value is not None
         )
@@ -155,6 +158,17 @@ def _url_quote(s):  # pylint: disable=invalid-name
     return quoted.replace("%", "%%")
 
 
+def _get_opentelemetry_values():
+    """
+    Return the OpenTelemetry Trace and Span IDs if Span ID is set in the
+    OpenTelemetry execution context.
+    """
+    # Insert the W3C TraceContext generated
+    _headers = {}
+    propagator.inject(_headers)
+    return _headers
+
+
 def _generate_opentelemetry_traceparent(span: Span) -> str:
     meta = {}
     _version = "00"