Don't use client defined session_id in open session

Don't use client defined "0xD01: optional THandleIdentifier sessionId" in TOpenSessionReq.
This is not part of the public Thriftserver protocol, and was implemented to be used only within Databricks. Remove it as not part of the "public" protocol and not used at this point.

There were no test of this functionality. When Databricks tried to use it, it turned out to not work. Therefore, removing.

Author: juliuszsompolski

cmdexec/clients/python/src/databricks/sql/client.py

@@ -55,8 +55,6 @@ def __init__(self,
         #   verification. If not provide, uses system truststore.
         # _tls_client_cert_file, _tls_client_cert_key_file
         #   Set client SSL certificate.
-        # _session_id
-        #   Specify the session id of the connection. For Redash use only.
         # _retry_stop_after_attempts_count
         #  The maximum number of attempts during a request retry sequence (defaults to 24)
 
@@ -93,8 +91,7 @@ def __init__(self,
             _connection_uri=kwargs.get("_connection_uri"),
             _retry_stop_after_attempts_count=kwargs.get("_retry_stop_after_attempts_count", 24))
 
-        self._session_handle = self.thrift_backend.open_session(
-            session_id=kwargs.get("_session_id"))
+        self._session_handle = self.thrift_backend.open_session()
         self.open = True
         logger.info("Successfully opened session " + str(self.get_session_id()))
         self._cursors = []  # type: List[Cursor]

cmdexec/clients/python/src/databricks/sql/thrift_backend.py

@@ -153,12 +153,10 @@ def _check_protocol_version(self, t_open_session_resp):
                                    "SPARK_CLI_SERVICE_PROTOCOL_V3, "
                                    "instead got: {}".format(protocol_version))
 
-    def open_session(self, session_id=None):
+    def open_session(self):
         try:
             self._transport.open()
-            handle_identifier = session_id and ttypes.THandleIdentifier(session_id, uuid4().bytes)
             open_session_req = ttypes.TOpenSessionReq(
-                sessionId=handle_identifier,
                 client_protocol_i64=ttypes.TProtocolVersion.SPARK_CLI_SERVICE_PROTOCOL_V4,
                 client_protocol=None,
                 configuration={

cmdexec/clients/python/tests/test_thrift_backend.py

@@ -609,15 +609,6 @@ def test_get_columns_calls_client_and_handle_execute_response(self, tcli_service
         # Check response handling
         thrift_backend._handle_execute_response.assert_called_with(response, cursor_mock)
 
-    @patch("databricks.sql.thrift_backend.TCLIService.Client")
-    def test_open_session_uses_user_provided_session_id(self, tcli_service_class):
-        tcli_service_instance = tcli_service_class.return_value
-        tcli_service_instance.OpenSession.return_value = self.open_session_resp
-
-        thrift_backend = ThriftBackend("foobar", 443, "path", [])
-        thrift_backend.open_session(0b111)
-        self.assertEqual(tcli_service_instance.OpenSession.call_args[0][0].sessionId.guid, 0b111)
-
     @patch("databricks.sql.thrift_backend.TCLIService.Client")
     def test_open_session_user_provided_session_id_optional(self, tcli_service_class):
         tcli_service_instance = tcli_service_class.return_value