Non-streaming simple fastapi server (#144)

cacheflow/entrypoints/openai/openai_frontend.py

@@ -233,7 +233,7 @@ async def create_completion(raw_request: Request):
     async for res in result_generator:
         if await raw_request.is_disconnected():
             # Abort the request if the client disconnects.
-            await server.abort(request_id)
+            await abort_request()
             return create_error_response(HTTPStatus.BAD_REQUEST,
                                          "Client disconnected")
         final_res = res

cacheflow/entrypoints/simple_fastapi_frontend.py

@@ -3,7 +3,7 @@ import json
 from typing import AsyncGenerator
 
 from fastapi import BackgroundTasks, FastAPI, Request
-from fastapi.responses import StreamingResponse
+from fastapi.responses import Response, StreamingResponse
 import uvicorn
 
 from cacheflow.sampling_params import SamplingParams
@@ -17,19 +17,22 @@ app = FastAPI()
 
 
 @app.post("/generate")
-async def generate_stream(request: Request) -> StreamingResponse:
+async def generate(request: Request) -> Response:
     """ Stream the results of the generation request.
 
     The request should be a JSON object with the following fields:
     - prompt: the prompt to use for the generation.
+    - stream: whether to stream the results or not.
     - other fields: the sampling parameters (See `SamplingParams` for details).
     """
     request_dict = await request.json()
     prompt = request_dict.pop("prompt")
+    stream = request_dict.pop("stream", False)
     sampling_params = SamplingParams(**request_dict)
     request_id = random_uuid()
     results_generator = server.generate(prompt, sampling_params, request_id)
 
+    # Streaming case
     async def stream_results() -> AsyncGenerator[bytes, None]:
         async for request_output in results_generator:
             prompt = request_output.prompt
@@ -37,19 +40,35 @@ async def generate_stream(request: Request) -> StreamingResponse:
                 prompt + output.text
                 for output in request_output.outputs
             ]
-            ret = {
-                "text": text_outputs,
-                "error": 0,
-            }
+            ret = {"text": text_outputs}
             yield (json.dumps(ret) + "\0").encode("utf-8")
 
     async def abort_request() -> None:
         await server.abort(request_id)
 
-    background_tasks = BackgroundTasks()
-    # Abort the request if the client disconnects.
-    background_tasks.add_task(abort_request)
-    return StreamingResponse(stream_results(), background=background_tasks)
+    if stream:
+        background_tasks = BackgroundTasks()
+        # Abort the request if the client disconnects.
+        background_tasks.add_task(abort_request)
+        return StreamingResponse(stream_results(), background=background_tasks)
+
+    # Non-streaming case
+    final_output = None
+    async for request_output in results_generator:
+        if await request.is_disconnected():
+            # Abort the request if the client disconnects.
+            await server.abort(request_id)
+            return Response(status_code=499)
+        final_output = request_output
+
+    assert final_output is not None
+    prompt = final_output.prompt
+    text_outputs = [
+        prompt + output.text
+        for output in final_output.outputs
+    ]
+    ret = {"text": text_outputs}
+    return Response(content=json.dumps(ret))
 
 
 if __name__ == "__main__":

examples/simple_fastapi_client.py

 import argparse
-import requests
 import json
+import requests
+from typing import Iterable, List
 
-def clear_line(n=1):
+def clear_line(n:int = 1) -> None:
     LINE_UP = '\033[1A'
     LINE_CLEAR = '\x1b[2K'
     for i in range(n):
         print(LINE_UP, end=LINE_CLEAR, flush=True)
 
 
-def http_request(prompt: str, api_url: str, n: int = 1):
+def post_http_request(prompt: str, api_url: str, n: int = 1,
+                      stream: bool = False) -> requests.Response:
     headers = {"User-Agent": "Test Client"}
     pload = {
         "prompt": prompt,
@@ -17,32 +19,52 @@ def http_request(prompt: str, api_url: str, n: int = 1):
         "use_beam_search": True,
         "temperature": 0.0,
         "max_tokens": 16,
+        "stream": stream,
     }
     response = requests.post(api_url, headers=headers, json=pload, stream=True)
+    return response
+
 
-    for chunk in response.iter_lines(chunk_size=8192, decode_unicode=False, delimiter=b"\0"):
+def get_streaming_response(response: requests.Response) -> Iterable[List[str]]:
+    for chunk in response.iter_lines(chunk_size=8192, decode_unicode=False,
+                                     delimiter=b"\0"):
         if chunk:
             data = json.loads(chunk.decode("utf-8"))
             output = data["text"]
             yield output
 
 
+def get_response(response: requests.Response) -> List[str]:
+    data = json.loads(response.content)
+    output = data["text"]
+    return output
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     parser.add_argument("--host", type=str, default="localhost")
     parser.add_argument("--port", type=int, default=8001)
     parser.add_argument("--n", type=int, default=4)
     parser.add_argument("--prompt", type=str, default="San Francisco is a")
+    parser.add_argument("--stream", action="store_true")
     args = parser.parse_args()
     prompt = args.prompt
     api_url = f"http://{args.host}:{args.port}/generate"
     n = args.n
+    stream = args.stream
 
     print(f"Prompt: {prompt}\n", flush=True)
-    num_printed_lines = 0
-    for h in http_request(prompt, api_url, n):
-        clear_line(num_printed_lines)
+    response = post_http_request(prompt, api_url, n, stream)
+
+    if stream:
         num_printed_lines = 0
-        for i, line in enumerate(h):
-            num_printed_lines += 1
+        for h in get_streaming_response(response):
+            clear_line(num_printed_lines)
+            num_printed_lines = 0
+            for i, line in enumerate(h):
+                num_printed_lines += 1
+                print(f"Beam candidate {i}: {line}", flush=True)
+    else:
+        output = get_response(response)
+        for i, line in enumerate(output):
             print(f"Beam candidate {i}: {line}", flush=True)