From b7954b65419a77169617be325e0b4a8b51a93af5 Mon Sep 17 00:00:00 2001
From: Daniel Lemm <61800298+ffe4@users.noreply.github.com>
Date: Thu, 3 Sep 2020 17:42:13 +0200
Subject: [PATCH] Add support for OTEL_LOG_LEVEL env var

---
 .../src/opentelemetry/sdk/__init__.py         | 22 +++++++
 .../tests/test_sdk_configuration.py           | 58 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 opentelemetry-sdk/tests/test_sdk_configuration.py

diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/__init__.py
index ca21f8b8609..29bf3324006 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/__init__.py
@@ -16,6 +16,28 @@
 The OpenTelemetry SDK package is an implementation of the OpenTelemetry
 API
 """
+import logging
+import os
+
 from . import metrics, trace, util
 
 __all__ = ["metrics", "trace", "util"]
+
+_LOG_LEVELS = {
+    "DEBUG": logging.DEBUG,
+    "INFO": logging.INFO,
+    "WARNING": logging.WARNING,
+    "ERROR": logging.ERROR,
+    "CRITICAL": logging.CRITICAL,
+}
+
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.INFO)
+if os.getenv("OTEL_LOG_LEVEL") is not None:
+    key = os.getenv("OTEL_LOG_LEVEL").upper()
+    if key in _LOG_LEVELS:
+        logger.setLevel(_LOG_LEVELS.get(key))
+    else:
+        logger.warning(
+            "Invalid value for environment variable OTEL_LOG_LEVEL. Defaulting to INFO."
+        )
diff --git a/opentelemetry-sdk/tests/test_sdk_configuration.py b/opentelemetry-sdk/tests/test_sdk_configuration.py
new file mode 100644
index 00000000000..b730a7a2098
--- /dev/null
+++ b/opentelemetry-sdk/tests/test_sdk_configuration.py
@@ -0,0 +1,58 @@
+import logging
+import unittest
+from importlib import reload
+from logging import CRITICAL, DEBUG, ERROR, INFO, WARNING
+from unittest.mock import patch
+
+from opentelemetry import sdk
+
+sdk_logger = logging.getLogger("opentelemetry.sdk")
+
+
+def reload_sdk_with_env(env_dict):
+    with patch.dict("os.environ", env_dict, clear=True):
+        reload(sdk)
+
+
+class TestLogLevelEnv(unittest.TestCase):
+    def tearDown(self):
+        """reload sdk to reset logging level"""
+        reload(sdk)
+
+    def test_loglevel_is_info_by_default(self):
+        reload_sdk_with_env({})
+        self.assertEqual(sdk_logger.getEffectiveLevel(), INFO)
+
+    def test_setting_log_level_env_to_valid_value(self):
+        valid_value_log_level_pairs = [
+            ("DEBUG", DEBUG),
+            ("INFO", INFO),
+            ("WARNING", WARNING),
+            ("ERROR", ERROR),
+            ("CRITICAL", CRITICAL),
+        ]
+        for value, log_level in valid_value_log_level_pairs:
+            reload_sdk_with_env({"OTEL_LOG_LEVEL": value})
+            self.assertEqual(sdk_logger.getEffectiveLevel(), log_level, value)
+
+    def test_log_level_is_propagated(self):
+        reload_sdk_with_env({"OTEL_LOG_LEVEL": "CRITICAL"})
+        self.assertEqual(sdk_logger.getEffectiveLevel(), CRITICAL)
+        self.assertEqual(
+            sdk_logger.getChild("trace").getEffectiveLevel(), CRITICAL
+        )
+        self.assertEqual(
+            sdk_logger.getChild("metrics").getEffectiveLevel(), CRITICAL
+        )
+        self.assertEqual(
+            sdk_logger.getChild("resources").getEffectiveLevel(), CRITICAL
+        )
+
+    def test_invalid_log_level_value_warns_and_defaults_to_info(self):
+        with self.assertLogs(level=WARNING):
+            reload_sdk_with_env({"OTEL_LOG_LEVEL": "NOT_A_VALID_LOG_LEVEL"})
+        self.assertEqual(sdk_logger.getEffectiveLevel(), INFO)
+
+    def test_log_level_is_case_insensitive(self):
+        reload_sdk_with_env({"OTEL_LOG_LEVEL": "cRiTiCaL"})
+        self.assertEqual(sdk_logger.getEffectiveLevel(), CRITICAL)