remove slicing reponse and add resume api (#154)

* Fix lmdeploy.serve.turbomind bug
* add __init__.py for turbomind
* add resume function
* fix the assignment for session.response

* Fix code style

lmdeploy/serve/turbomind/__init__.py

+# Copyright (c) OpenMMLab. All rights reserved.

lmdeploy/serve/turbomind/chatbot.py

@@ -259,6 +259,47 @@ class Chatbot:
             logger.info(f'cancel session {session_id} failed: {res}')
         return status
 
+    def resume(self, session_id: int, *args, **kwargs):
+        """Resume a session by sending the history conversations to triton
+        inference server. After resuming, users can continue chatting with
+        chatbot.
+
+        Args:
+            session_id (int): the identical id of a session
+
+        Returns:
+            int: 0: success, -1: session not found
+        """
+        assert isinstance(session_id, int), \
+            f'INT session id is required, but got {type(session_id)}'
+
+        logger = get_logger(log_level=self.log_level)
+        logger.info(f'resume session: {session_id}')
+
+        if self._session is None:
+            logger.error(
+                f"session {session_id} doesn't exist. It cannot be recovered")
+            return StatusCode.TRITON_SESSION_INVALID_ARG
+        if self._session.session_id != session_id:
+            logger.error(
+                f'you cannot resume session {session_id}, because this '
+                f'session is {self._session.session_id}')
+            return StatusCode.TRITON_SESSION_INVALID_ARG
+
+        self._session.status = 1
+        self._session.sequence_length = 0
+        histories = self._session.histories
+        for status, _, _ in self._stream_infer(self._session,
+                                               prompt=histories,
+                                               request_output_len=0,
+                                               sequence_start=True,
+                                               sequence_end=False):
+            if status.value < 0:
+                return status
+
+        self._session.histories = histories
+        return status
+
     def reset_session(self):
         """reset session."""
         self._session = None
@@ -553,7 +594,6 @@ class Chatbot:
             except Exception as e:
                 logger.error(f'catch exception: {e}')
 
-        session.response = session.response[len(session.prompt):]
         # put session back to queue so that `_stream_infer` can update it in
         # `self.sessions`
         while not res_queue.empty():