Add client id to all request headers

sdk/cosmos/azure-cosmos/CHANGELOG.md

@@ -9,6 +9,7 @@
 #### Bugs Fixed
 
 #### Other Changes
+* Changed to include client id in headers for all requests. See [PR 42104](https://github.com/Azure/azure-sdk-for-python/pull/42104).
 
 ### 4.14.0b1 (2025-07-14)
 

sdk/cosmos/azure-cosmos/azure/cosmos/_base.py

@@ -291,6 +291,8 @@ def GetHeaders(  # pylint: disable=too-many-statements,too-many-branches
 
     if client_id is not None:
         headers[http_constants.HttpHeaders.ClientId] = client_id
+    elif cosmos_client_connection and cosmos_client_connection.client_id:
+        headers[http_constants.HttpHeaders.ClientId] = cosmos_client_connection.client_id
 
     if options.get("enableScriptLogging"):
         headers[http_constants.HttpHeaders.EnableScriptLogging] = options["enableScriptLogging"]

sdk/cosmos/azure-cosmos/azure/cosmos/_cosmos_client_connection.py

@@ -2825,7 +2825,8 @@ def Read(
             options = {}
 
         initial_headers = initial_headers or self.default_headers
-        headers = base.GetHeaders(self, initial_headers, "get", path, id, typ, documents._OperationType.Read, options)
+        headers = base.GetHeaders(self, initial_headers, "get", path, id, typ, documents._OperationType.Read,
+                                  options)
         # Read will use ReadEndpoint since it uses GET operation
         request_params = RequestObject(typ, documents._OperationType.Read, headers)
         request_params.set_excluded_location_from_options(options)

sdk/cosmos/azure-cosmos/tests/test_headers.py

@@ -56,6 +56,11 @@ def side_effect_correlated_activity_id(self, *args, **kwargs):
         assert args[3]["x-ms-cosmos-correlated-activityid"]  # cspell:disable-line
         raise StopIteration
 
+    def side_effect_client_id(self, *args, **kwargs):
+        # Extract request headers from args
+        assert args[2][http_constants.HttpHeaders.ClientId]
+        raise StopIteration
+
     def test_correlated_activity_id(self):
         query = 'SELECT * from c ORDER BY c._ts'
 
@@ -98,6 +103,20 @@ def test_negative_max_integrated_cache_staleness(self):
         except Exception as exception:
             assert isinstance(exception, ValueError)
 
+    def test_client_id(self):
+        # Client ID should be sent on every request, Verify it is sent on a read_item request
+        cosmos_client_connection = self.container.client_connection
+        original_connection_get = cosmos_client_connection._CosmosClientConnection__Get
+        cosmos_client_connection._CosmosClientConnection__Get = MagicMock(
+            side_effect=self.side_effect_client_id)
+        try:
+            self.container.read_item(item="id-1", partition_key="pk-1")
+        except StopIteration:
+            pass
+        finally:
+            cosmos_client_connection._CosmosClientConnection__Get = original_connection_get
+
+
     def test_client_level_throughput_bucket(self):
         cosmos_client.CosmosClient(self.host, self.masterKey,
             throughput_bucket=client_throughput_bucket_number,

sdk/cosmos/azure-cosmos/tests/test_headers_async.py

@@ -2,14 +2,14 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 
 import unittest
+from unittest.mock import MagicMock
 
 import pytest
 import uuid
 
 
 import test_config
 from azure.cosmos import http_constants
-import azure.cosmos.exceptions as exceptions
 from azure.cosmos.aio import CosmosClient, _retry_utility_async, DatabaseProxy
 from azure.cosmos.partition_key import PartitionKey
 
@@ -23,6 +23,12 @@ async def request_raw_response_hook(response):
     assert (response.http_request.headers[http_constants.HttpHeaders.ThroughputBucket]
             == str(request_throughput_bucket_number))
 
+
+class ClientIDVerificationError(Exception):
+    """Custom exception for client ID verification errors."""
+    pass
+
+
 @pytest.mark.cosmosEmulator
 class TestHeadersAsync(unittest.IsolatedAsyncioTestCase):
     client: CosmosClient = None
@@ -206,5 +212,24 @@ async def test_container_read_item_negative_throughput_bucket_async(self):
             assert "specified for the header 'x-ms-cosmos-throughput-bucket' is invalid." in e.http_error_message
     """
 
+    async def side_effect_client_id(self, *args, **kwargs):
+        # This is a side effect to verify that the client ID is sent in the request headers
+        assert args[2].get(http_constants.HttpHeaders.ClientId) is not None
+        raise ClientIDVerificationError("Client ID verification complete")
+
+    async def test_client_id(self):
+        # Client ID should be sent on every request, Verify it is sent on a read_item request
+        cosmos_client_connection = self.container.client_connection
+        original_connection_get = cosmos_client_connection._CosmosClientConnection__Get
+        cosmos_client_connection._CosmosClientConnection__Get = MagicMock(
+            side_effect=self.side_effect_client_id)
+        try:
+            await self.container.read_item(item="id-1", partition_key="pk-1")
+        except ClientIDVerificationError:
+            pass
+        finally:
+            cosmos_client_connection._CosmosClientConnection__Get = original_connection_get
+
+
 if __name__ == "__main__":
     unittest.main()