Logging: Defensively access provider resource

Now service name is extracted from the provider defensively and lazily.
This accounts for an SDK that does not provide access to "resource" via
TracerProviders and for lazy initialization of TracerProviders.

Fixes #810

Author: owais

Diff for: CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.9.1-0.28b1...HEAD)
 
+### Fixed
+
+- `opentelemetry-instrumentation-logging` retrieves service name defensively.
+  ([#890](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/890))
+
 ## [1.9.1-0.28b1](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.9.1-0.28b1) - 2022-01-29
 
 

Diff for: instrumentation/opentelemetry-instrumentation-logging/src/opentelemetry/instrumentation/logging/__init__.py

@@ -16,7 +16,7 @@
 
 import logging  # pylint: disable=import-self
 from os import environ
-from typing import Collection
+from typing import Collection, Optional
 
 from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.instrumentation.logging.constants import (
@@ -76,20 +76,29 @@ def instrumentation_dependencies(self) -> Collection[str]:
         return _instruments
 
     def _instrument(self, **kwargs):
-        service_name = ""
-        provider = kwargs.get("tracer_provider", None) or get_tracer_provider()
-        resource = provider.resource if provider else None
-        if resource:
-            service_name = resource.attributes.get("service.name")
 
+        provider = kwargs.get("tracer_provider", None) or get_tracer_provider()
         old_factory = logging.getLogRecordFactory()
         LoggingInstrumentor._old_factory = old_factory
 
+        service_name = None
+
         def record_factory(*args, **kwargs):
             record = old_factory(*args, **kwargs)
 
             record.otelSpanID = "0"
             record.otelTraceID = "0"
+
+            nonlocal service_name
+            if service_name is None:
+                resource = getattr(provider, "resource", None)
+                if resource:
+                    service_name = (
+                        resource.attributes.get("service.name") or ""
+                    )
+                else:
+                    service_name = ""
+
             record.otelServiceName = service_name
 
             span = get_current_span()

Diff for: instrumentation/opentelemetry-instrumentation-logging/tests/test_logging.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import logging
+from typing import Optional
 from unittest import mock
 
 import pytest
@@ -22,7 +23,41 @@
     LoggingInstrumentor,
 )
 from opentelemetry.test.test_base import TestBase
-from opentelemetry.trace import get_tracer
+from opentelemetry.trace import ProxyTracer, get_tracer
+
+
+class FakeTracerProvider:
+    def get_tracer(
+        self,
+        instrumenting_module_name: str,
+        instrumenting_library_version: Optional[str] = None,
+        schema_url: Optional[str] = None,
+    ) -> ProxyTracer:
+        return ProxyTracer()
+
+
+class TestLoggingInstrumentorProxyTracerProvider(TestBase):
+    @pytest.fixture(autouse=True)
+    def inject_fixtures(self, caplog):
+        self.caplog = caplog  # pylint: disable=attribute-defined-outside-init
+
+    def setUp(self):
+        super().setUp()
+        LoggingInstrumentor().instrument(tracer_provider=FakeTracerProvider())
+
+    def tearDown(self):
+        super().tearDown()
+        LoggingInstrumentor().uninstrument()
+
+    def test_trace_context_injection(self):
+        with self.caplog.at_level(level=logging.INFO):
+            logger = logging.getLogger("test logger")
+            logger.info("hello")
+            self.assertEqual(len(self.caplog.records), 1)
+            record = self.caplog.records[0]
+            self.assertEqual(record.otelSpanID, "0")
+            self.assertEqual(record.otelTraceID, "0")
+            self.assertEqual(record.otelServiceName, "")
 
 
 class TestLoggingInstrumentor(TestBase):