Fix bagage key lowercasing

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#3128](https://github.com/open-telemetry/opentelemetry-python/pull/3128))
 - Fix validation of baggage values
   ([#3058](https://github.com/open-telemetry/opentelemetry-python/pull/3058))
+- Fix capitalization of baggage keys
+  ([#3151](https://github.com/open-telemetry/opentelemetry-python/pull/3151))
 
 ## Version 1.15.0/0.36b0 (2022-12-09)
 

opentelemetry-api/src/opentelemetry/baggage/propagation/__init__.py

@@ -93,7 +93,7 @@ def extract(
                 _logger.warning("Invalid baggage entry: `%s`", entry)
                 continue
 
-            name = unquote_plus(name).strip().lower()
+            name = unquote_plus(name).strip()
             value = unquote_plus(value).strip()
 
             context = set_baggage(

opentelemetry-api/tests/baggage/propagation/test_propagation.py

@@ -0,0 +1,39 @@
+# 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
+
+from unittest import TestCase
+
+from opentelemetry.baggage import get_baggage, set_baggage
+from opentelemetry.baggage.propagation import W3CBaggagePropagator
+
+
+class TestBaggageManager(TestCase):
+    def test_propagate_baggage(self):
+        carrier = {}
+        propagator = W3CBaggagePropagator()
+
+        ctx = set_baggage("Test1", "value1")
+        ctx = set_baggage("test2", "value2", context=ctx)
+
+        propagator.inject(carrier, ctx)
+        ctx_propagated = propagator.extract(carrier)
+
+        self.assertEqual(
+            get_baggage("Test1", context=ctx_propagated), "value1"
+        )
+        self.assertEqual(
+            get_baggage("test2", context=ctx_propagated), "value2"
+        )