Expose close() method in botocore.client instances

- Enable pooled/keep-alive connections to be closed explicitly
- Add tests for client, endpoint & session close()

botocore/client.py

@@ -839,6 +839,10 @@ def __getattr__(self, item):
             f"'{self.__class__.__name__}' object has no attribute '{item}'"
         )
 
+    def close(self):
+        """Closes underlying endpoint connections."""
+        self._endpoint.close()
+
     def _register_handlers(self):
         # Register the handler required to sign requests.
         service_id = self.meta.service_model.service_id.hyphenize()

botocore/endpoint.py

@@ -107,6 +107,9 @@ def __init__(
     def __repr__(self):
         return f'{self._endpoint_prefix}({self.host})'
 
+    def close(self):
+        self.http_session.close()
+
     def make_request(self, operation_model, request_dict):
         logger.debug(
             "Making request for %s with params: %s",

botocore/httpsession.py

@@ -423,6 +423,11 @@ def _chunked(self, headers):
         transfer_encoding = ensure_bytes(transfer_encoding)
         return transfer_encoding.lower() == b'chunked'
 
+    def close(self):
+        self._manager.clear()
+        for manager in self._proxy_managers.values():
+            manager.clear()
+
     def send(self, request):
         try:
             proxy_url = self._proxy_config.proxy_url_for(request.url)

tests/unit/test_client.py

@@ -1585,6 +1585,15 @@ def test_client_operation_hostname_binding_configuration(self):
         request_dict = self.endpoint.make_request.call_args[0][1]
         self.assertEqual(request_dict['url'], expected_url)
 
+    def test_client_close(self):
+        creator = self.create_client_creator()
+        service_client = creator.create_client(
+            'myservice', 'us-west-2', credentials=self.credentials
+        )
+
+        service_client.close()
+        self.endpoint.close.assert_called_once_with()
+
 
 class TestClientErrors(TestAutoGeneratedClient):
     def add_error_response(self, error_response):

tests/unit/test_endpoint.py

@@ -201,6 +201,10 @@ def test_parses_modeled_exception_fields(self):
         }
         self.assertEqual(response, expected_response)
 
+    def test_close(self):
+        self.endpoint.close()
+        self.endpoint.http_session.close.assert_called_once_with()
+
 
 class TestRetryInterface(TestEndpointBase):
     def setUp(self):

tests/unit/test_http_session.py

@@ -496,3 +496,23 @@ def test_chunked_encoding_is_not_set_without_header(self):
 
         session.send(self.request.prepare())
         self.assert_request_sent(chunked=False)
+
+    def test_close(self):
+        session = URLLib3Session()
+        session.close()
+        self.pool_manager.clear.assert_called_once_with()
+
+    def test_close_proxied(self):
+        proxies = {'https': 'http://proxy.com', 'http': 'http://proxy2.com'}
+        session = URLLib3Session(proxies=proxies)
+        for proxy, proxy_url in proxies.items():
+            self.request.url = '%s://example.com/' % proxy
+            session.send(self.request.prepare())
+
+        session.close()
+        self.proxy_manager_fun.return_value.clear.assert_called_with()
+        # One call for pool manager, one call for each of the proxies
+        self.assertEqual(
+            self.proxy_manager_fun.return_value.clear.call_count,
+            1 + len(proxies),
+        )