Add global LogEmitterProvider and convenience function get_log_emitter (open-telemetry#1901)

srikanthccv · lzchen · commit 99ec1acbdd4e · 2021-11-03T17:32:17.000-07:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -115,6 +115,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added dropped count to otlp, jaeger and zipkin exporters.
   ([#1893](https://github.com/open-telemetry/opentelemetry-python/pull/1893))
 
+### Added
+- Add global LogEmitterProvider and convenience function get_log_emitter
+  ([#1901](https://github.com/open-telemetry/opentelemetry-python/pull/1901))
+
 ### Changed
 - Updated `opentelemetry-opencensus-exporter` to use `service_name` of spans instead of resource
   ([#1897](https://github.com/open-telemetry/opentelemetry-python/pull/1897))
diff --git a/opentelemetry-sdk/setup.cfg b/opentelemetry-sdk/setup.cfg
@@ -54,6 +54,8 @@ opentelemetry_tracer_provider =
     sdk_tracer_provider = opentelemetry.sdk.trace:TracerProvider
 opentelemetry_traces_exporter =
     console = opentelemetry.sdk.trace.export:ConsoleSpanExporter
+opentelemetry_log_emitter_provider =
+    sdk_log_emitter_provider = opentelemetry.sdk.logs:LogEmitterProvider
 opentelemetry_id_generator =
     random = opentelemetry.sdk.trace.id_generator:RandomIdGenerator
 opentelemetry_environment_variables =
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/environment_variables.py b/opentelemetry-sdk/src/opentelemetry/sdk/environment_variables.py
@@ -369,3 +369,12 @@
 
 If both are set, :envvar:`OTEL_SERVICE_NAME` takes precedence.
 """
+
+OTEL_PYTHON_LOG_EMITTER_PROVIDER = "OTEL_PYTHON_LOG_EMITTER_PROVIDER"
+"""
+.. envvar:: OTEL_PYTHON_LOG_EMITTER_PROVIDER
+
+The :envvar:`OTEL_PYTHON_LOG_EMITTER_PROVIDER` environment variable allows users to
+provide the entry point for loading the log emitter provider. If not specified, SDK
+LogEmitterProvider is used.
+"""
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/logs/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/logs/__init__.py
@@ -14,14 +14,22 @@
 
 import abc
 import atexit
-from typing import Any, Optional
+import logging
+import os
+from typing import Any, Optional, cast
 
+from opentelemetry.sdk.environment_variables import (
+    OTEL_PYTHON_LOG_EMITTER_PROVIDER,
+)
 from opentelemetry.sdk.logs.severity import SeverityNumber
 from opentelemetry.sdk.resources import Resource
 from opentelemetry.sdk.util.instrumentation import InstrumentationInfo
 from opentelemetry.trace.span import TraceFlags
+from opentelemetry.util._providers import _load_provider
 from opentelemetry.util.types import Attributes
 
+_logger = logging.getLogger(__name__)
+
 
 class LogRecord:
     """A LogRecord instance represents an event being logged.
@@ -172,3 +180,60 @@ def force_flush(self, timeout_millis: int = 30000) -> bool:
             False otherwise.
         """
         # TODO: multi_log_processor.force_flush
+
+
+_LOG_EMITTER_PROVIDER = None
+
+
+def get_log_emitter_provider() -> LogEmitterProvider:
+    """Gets the current global :class:`~.LogEmitterProvider` object."""
+    global _LOG_EMITTER_PROVIDER  # pylint: disable=global-statement
+    if _LOG_EMITTER_PROVIDER is None:
+        if OTEL_PYTHON_LOG_EMITTER_PROVIDER not in os.environ:
+            _LOG_EMITTER_PROVIDER = LogEmitterProvider()
+            return _LOG_EMITTER_PROVIDER
+
+        _LOG_EMITTER_PROVIDER = cast(
+            "LogEmitterProvider",
+            _load_provider(
+                OTEL_PYTHON_LOG_EMITTER_PROVIDER, "log_emitter_provider"
+            ),
+        )
+
+    return _LOG_EMITTER_PROVIDER
+
+
+def set_log_emitter_provider(log_emitter_provider: LogEmitterProvider) -> None:
+    """Sets the current global :class:`~.LogEmitterProvider` object.
+
+    This can only be done once, a warning will be logged if any furter attempt
+    is made.
+    """
+    global _LOG_EMITTER_PROVIDER  # pylint: disable=global-statement
+
+    if _LOG_EMITTER_PROVIDER is not None:
+        _logger.warning(
+            "Overriding of current LogEmitterProvider is not allowed"
+        )
+        return
+
+    _LOG_EMITTER_PROVIDER = log_emitter_provider
+
+
+def get_log_emitter(
+    instrumenting_module_name: str,
+    instrumenting_library_version: str = "",
+    log_emitter_provider: Optional[LogEmitterProvider] = None,
+) -> LogEmitter:
+    """Returns a `LogEmitter` for use within a python process.
+
+    This function is a convenience wrapper for
+    opentelemetry.sdk.logs.LogEmitterProvider.get_log_emitter.
+
+    If log_emitter_provider param is omitted the current configured one is used.
+    """
+    if log_emitter_provider is None:
+        log_emitter_provider = get_log_emitter_provider()
+    return log_emitter_provider.get_log_emitter(
+        instrumenting_module_name, instrumenting_library_version
+    )
diff --git a/opentelemetry-sdk/tests/logs/__init__.py b/opentelemetry-sdk/tests/logs/__init__.py
@@ -0,0 +1,13 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
diff --git a/opentelemetry-sdk/tests/logs/test_global_provider.py b/opentelemetry-sdk/tests/logs/test_global_provider.py
@@ -0,0 +1,75 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+
+# type:ignore
+import unittest
+from importlib import reload
+from logging import WARNING
+from unittest.mock import patch
+
+from opentelemetry.sdk import logs
+from opentelemetry.sdk.environment_variables import (
+    OTEL_PYTHON_LOG_EMITTER_PROVIDER,
+)
+from opentelemetry.sdk.logs import (
+    LogEmitterProvider,
+    get_log_emitter_provider,
+    set_log_emitter_provider,
+)
+
+
+class TestGlobals(unittest.TestCase):
+    def tearDown(self):
+        reload(logs)
+
+    def check_override_not_allowed(self):
+        """set_log_emitter_provider should throw a warning when overridden"""
+        provider = get_log_emitter_provider()
+        with self.assertLogs(level=WARNING) as test:
+            set_log_emitter_provider(LogEmitterProvider())
+            self.assertEqual(
+                test.output,
+                [
+                    (
+                        "WARNING:opentelemetry.sdk.logs:Overriding of current "
+                        "LogEmitterProvider is not allowed"
+                    )
+                ],
+            )
+        self.assertIs(provider, get_log_emitter_provider())
+
+    def test_set_tracer_provider(self):
+        reload(logs)
+        provider = LogEmitterProvider()
+        set_log_emitter_provider(provider)
+        retrieved_provider = get_log_emitter_provider()
+        self.assertEqual(provider, retrieved_provider)
+
+    def test_tracer_provider_override_warning(self):
+        reload(logs)
+        self.check_override_not_allowed()
+
+    @patch.dict(
+        "os.environ",
+        {OTEL_PYTHON_LOG_EMITTER_PROVIDER: "sdk_log_emitter_provider"},
+    )
+    def test_sdk_log_emitter_provider(self):
+        reload(logs)
+        self.check_override_not_allowed()
+
+    @patch.dict("os.environ", {OTEL_PYTHON_LOG_EMITTER_PROVIDER: "unknown"})
+    def test_unknown_log_emitter_provider(self):
+        reload(logs)
+        with self.assertRaises(Exception):
+            get_log_emitter_provider()
