[chore] updates to the envcarrier with tests

Author: adrielp

opentelemetry-api/src/opentelemetry/propagators/envcarrier.py

@@ -1,45 +1,92 @@
+# 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.
+
 import os
 import typing
+
 from opentelemetry.propagators.textmap import Getter, Setter
 
+
 class EnvironmentGetter(Getter[dict]):
-    """This class decorates Getter to enable extracting from context and baggage
-    from environment variables.
+    """Getter implementation for extracting context and baggage from environment variables.
+
+    EnvironmentGetter creates a case-insensitive lookup from the current environment
+    variables and provides simple data access without validation.
+
+    Example usage:
+        getter = EnvironmentGetter()
+        traceparent = getter.get({}, "traceparent")
     """
-    
+
     def __init__(self):
-        self.env_copy = dict(os.environ)
-        self.carrier = {}
-        
-        for env_key, env_value in self.env_copy.items():
-            self.carrier[env_key.lower()] = env_value
-    
-    def get(self, carrier: dict, key: str) -> typing.Optional[typing.List[str]]:
-        """Get a value from the carrier for the given key"""
-        val = self.carrier.get(key, None)
+        # Create case-insensitive lookup from current environment
+        self.carrier = {k.lower(): v for k, v in os.environ.items()}
+
+    def get(
+        self, carrier: dict, key: str
+    ) -> typing.Optional[typing.List[str]]:
+        """Get a value from the environment for the given key.
+
+        Args:
+            carrier: Not used for environment getter, maintained for interface compatibility
+            key: The key to look up (case-insensitive)
+
+        Returns:
+            A list with a single string value if the key exists, None otherwise.
+        """
+        val = self.carrier.get(key.lower())
         if val is None:
             return None
         if isinstance(val, typing.Iterable) and not isinstance(val, str):
             return list(val)
         return [val]
-    
+
     def keys(self, carrier: dict) -> typing.List[str]:
-        """Get all keys from the carrier"""
+        """Get all keys from the environment carrier.
+
+        Args:
+            carrier: Not used for environment getter, maintained for interface compatibility
+
+        Returns:
+            List of all environment variable keys (lowercase).
+        """
         return list(self.carrier.keys())
 
+
 class EnvironmentSetter(Setter[dict]):
-    """This class decorates Setter to enable setting context and baggage
-    to environment variables.
+    """Setter implementation for building environment variable dictionaries.
+
+    EnvironmentSetter builds a dictionary of environment variables that
+    can be passed to utilities like subprocess.run()
+
+    Example usage:
+        setter = EnvironmentSetter()
+        env_vars = {}
+        setter.set(env_vars, "traceparent", "00-trace-id-span-id-01")
+        subprocess.run(myCommand, env=env_vars)
     """
 
-    def set(self, carrier: typing.Optional[dict], key: str, value: str) -> None:
-        """Set a value in the environment for the given key.
-        
+    def set(
+        self, carrier: typing.Optional[dict], key: str, value: str
+    ) -> None:
+        """Set a value in the carrier dictionary for the given key.
+
         Args:
-            carrier: Not used for environment setter, but kept for interface compatibility
-            key: The key to set
+            carrier: Dictionary to store environment variables, created if None
+            key: The key to set (will be converted to uppercase)
             value: The value to set
         """
-        env_key = key.upper()
-        
-        os.environ[env_key] = value
+        if carrier is None:
+            carrier = {}
+        carrier[key.upper()] = value