disentangle model from tuner and rename modules

Former-commit-id: 02cbf91e7e424f8379c1fed01b82a5f7a83b6947

src/llmtuner/api/app.py

@@ -1,14 +1,8 @@
 import json
-import uvicorn
-from fastapi import FastAPI, HTTPException, status
-from fastapi.middleware.cors import CORSMiddleware
-from contextlib import asynccontextmanager
-from sse_starlette import EventSourceResponse
 from typing import List, Tuple
 from pydantic import BaseModel
+from contextlib import asynccontextmanager
 
-from llmtuner.extras.misc import torch_gc
-from llmtuner.chat import ChatModel
 from llmtuner.api.protocol import (
     Role,
     Finish,
@@ -23,10 +17,28 @@ from llmtuner.api.protocol import (
     ChatCompletionResponseStreamChoice,
     ChatCompletionResponseUsage
 )
+from llmtuner.chat import ChatModel
+from llmtuner.extras.misc import torch_gc
+from llmtuner.extras.packages import (
+    is_fastapi_availble, is_starlette_available, is_uvicorn_available
+)
+
+
+if is_fastapi_availble():
+    from fastapi import FastAPI, HTTPException, status
+    from fastapi.middleware.cors import CORSMiddleware
+
+
+if is_starlette_available():
+    from sse_starlette import EventSourceResponse
+
+
+if is_uvicorn_available():
+    import uvicorn
 
 
 @asynccontextmanager
-async def lifespan(app: FastAPI): # collects GPU memory
+async def lifespan(app: "FastAPI"): # collects GPU memory
     yield
     torch_gc()
 
@@ -38,7 +50,7 @@ def to_json(data: BaseModel) -> str:
         return data.json(exclude_unset=True, ensure_ascii=False)
 
 
-def create_app(chat_model: ChatModel) -> FastAPI:
+def create_app(chat_model: "ChatModel") -> "FastAPI":
     app = FastAPI(lifespan=lifespan)
 
     app.add_middleware(
@@ -56,12 +68,12 @@ def create_app(chat_model: ChatModel) -> FastAPI:
 
     @app.post("/v1/chat/completions", response_model=ChatCompletionResponse, status_code=status.HTTP_200_OK)
     async def create_chat_completion(request: ChatCompletionRequest):
-        if len(request.messages) < 1 or request.messages[-1].role != Role.USER:
+        if len(request.messages) == 0 or request.messages[-1].role != Role.USER:
             raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid request")
 
         query = request.messages[-1].content
         prev_messages = request.messages[:-1]
-        if len(prev_messages) > 0 and prev_messages[0].role == Role.SYSTEM:
+        if len(prev_messages) and prev_messages[0].role == Role.SYSTEM:
             system = prev_messages.pop(0).content
         else:
             system = None
@@ -73,12 +85,14 @@ def create_app(chat_model: ChatModel) -> FastAPI:
                     history.append([prev_messages[i].content, prev_messages[i+1].content])
                 else:
                     raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Only supports u/a/u/a/u...")
+        else:
+            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Only supports u/a/u/a/u...")
 
         if request.stream:
             generate = predict(query, history, system, request)
             return EventSourceResponse(generate, media_type="text/event-stream")
 
-        response, (prompt_length, response_length) = chat_model.chat(
+        responses = chat_model.chat(
             query, history, system,
             do_sample=request.do_sample,
             temperature=request.temperature,
@@ -87,18 +101,23 @@ def create_app(chat_model: ChatModel) -> FastAPI:
             num_return_sequences=request.n
         )
 
+        prompt_length, response_length = 0, 0
+        choices = []
+        for i, response in enumerate(responses):
+            choices.append(ChatCompletionResponseChoice(
+                index=i,
+                message=ChatMessage(role=Role.ASSISTANT, content=response.response_text),
+                finish_reason=Finish.STOP if response.finish_reason == "stop" else Finish.LENGTH
+            ))
+            prompt_length = response.prompt_length
+            response_length += response.response_length
+
         usage = ChatCompletionResponseUsage(
             prompt_tokens=prompt_length,
             completion_tokens=response_length,
             total_tokens=prompt_length+response_length
         )
 
-        choices = [ChatCompletionResponseChoice(
-            index=i,
-            message=ChatMessage(role=Role.ASSISTANT, content=choice),
-            finish_reason=Finish.STOP
-        ) for i, choice in enumerate(response)]
-
         return ChatCompletionResponse(model=request.model, choices=choices, usage=usage)
 
     async def predict(query: str, history: List[Tuple[str, str]], system: str, request: ChatCompletionRequest):