Make forward asynchrone to avoid long computation timing out.

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

src/transformers/commands/serving.py

 import logging
 from argparse import ArgumentParser, Namespace
-from typing import Any, List, Optional, Union
+from typing import Any, List, Optional
+
+from starlette.responses import JSONResponse
 
 from transformers import Pipeline
 from transformers.commands import BaseTransformersCLICommand
@@ -10,6 +12,7 @@ from transformers.pipelines import SUPPORTED_TASKS, pipeline
 try:
     from uvicorn import run
     from fastapi import FastAPI, HTTPException, Body
+    from fastapi.routing import APIRoute
     from pydantic import BaseModel
 
     _serve_dependancies_installed = True
@@ -37,7 +40,7 @@ def serve_command_factory(args: Namespace):
         tokenizer=args.tokenizer,
         device=args.device,
     )
-    return ServeCommand(nlp, args.host, args.port)
+    return ServeCommand(nlp, args.host, args.port, args.workers)
 
 
 class ServeModelInfoResult(BaseModel):
@@ -89,6 +92,7 @@ class ServeCommand(BaseTransformersCLICommand):
         )
         serve_parser.add_argument("--host", type=str, default="localhost", help="Interface the server will listen on.")
         serve_parser.add_argument("--port", type=int, default=8888, help="Port the serving will listen to.")
+        serve_parser.add_argument("--workers", type=int, default=1, help="Number of http workers")
         serve_parser.add_argument("--model", type=str, help="Model's name or path to stored model.")
         serve_parser.add_argument("--config", type=str, help="Model's config name or path to stored model.")
         serve_parser.add_argument("--tokenizer", type=str, help="Tokenizer name to use.")
@@ -100,12 +104,14 @@ class ServeCommand(BaseTransformersCLICommand):
         )
         serve_parser.set_defaults(func=serve_command_factory)
 
-    def __init__(self, pipeline: Pipeline, host: str, port: int):
+    def __init__(self, pipeline: Pipeline, host: str, port: int, workers: int):
 
         self._pipeline = pipeline
 
-        self._host = host
-        self._port = port
+        self.host = host
+        self.port = port
+        self.workers = workers
+
         if not _serve_dependancies_installed:
             raise RuntimeError(
                 "Using serve command requires FastAPI and unicorn. "
@@ -114,18 +120,42 @@ class ServeCommand(BaseTransformersCLICommand):
             )
         else:
             logger.info("Serving model over {}:{}".format(host, port))
-            self._app = FastAPI()
-
-            # Register routes
-            self._app.add_api_route("/", self.model_info, response_model=ServeModelInfoResult, methods=["GET"])
-            self._app.add_api_route("/tokenize", self.tokenize, response_model=ServeTokenizeResult, methods=["POST"])
-            self._app.add_api_route(
-                "/detokenize", self.detokenize, response_model=ServeDeTokenizeResult, methods=["POST"]
+            self._app = FastAPI(
+                routes=[
+                    APIRoute(
+                        "/",
+                        self.model_info,
+                        response_model=ServeModelInfoResult,
+                        response_class=JSONResponse,
+                        methods=["GET"],
+                    ),
+                    APIRoute(
+                        "/tokenize",
+                        self.tokenize,
+                        response_model=ServeTokenizeResult,
+                        response_class=JSONResponse,
+                        methods=["POST"],
+                    ),
+                    APIRoute(
+                        "/detokenize",
+                        self.detokenize,
+                        response_model=ServeDeTokenizeResult,
+                        response_class=JSONResponse,
+                        methods=["POST"],
+                    ),
+                    APIRoute(
+                        "/forward",
+                        self.forward,
+                        response_model=ServeForwardResult,
+                        response_class=JSONResponse,
+                        methods=["POST"],
+                    ),
+                ],
+                timeout=600,
             )
-            self._app.add_api_route("/forward", self.forward, response_model=ServeForwardResult, methods=["POST"])
 
     def run(self):
-        run(self._app, host=self._host, port=self._port)
+        run(self._app, host=self.host, port=self.port, workers=self.workers)
 
     def model_info(self):
         return ServeModelInfoResult(infos=vars(self._pipeline.model.config))
@@ -166,7 +196,7 @@ class ServeCommand(BaseTransformersCLICommand):
         except Exception as e:
             raise HTTPException(status_code=500, detail={"model": "", "error": str(e)})
 
-    def forward(self, inputs: Union[str, dict, List[str], List[int], List[dict]] = Body(None, embed=True)):
+    async def forward(self, inputs=Body(None, embed=True)):
         """
         **inputs**:
         **attention_mask**:

src/transformers/file_utils.py

@@ -28,8 +28,9 @@ from . import __version__
 logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
 
 try:
-    if os.environ.get("USE_TORCH", 'AUTO').upper() in ("1", "ON", "YES", "AUTO") and \
-            os.environ.get("USE_TF", 'AUTO').upper() not in ("1", "ON", "YES"):
+    USE_TF = os.environ.get("USE_TF", "AUTO").upper()
+    USE_TORCH = os.environ.get("USE_TORCH", "AUTO").upper()
+    if USE_TORCH in ("1", "ON", "YES", "AUTO") and USE_TF not in ("1", "ON", "YES"):
         import torch
 
         _torch_available = True  # pylint: disable=invalid-name
@@ -41,8 +42,10 @@ except ImportError:
     _torch_available = False  # pylint: disable=invalid-name
 
 try:
-    if os.environ.get("USE_TF", 'AUTO').upper() in ("1", "ON", "YES", "AUTO") and \
-            os.environ.get("USE_TORCH", 'AUTO').upper() not in ("1", "ON", "YES"):
+    USE_TF = os.environ.get("USE_TF", "AUTO").upper()
+    USE_TORCH = os.environ.get("USE_TORCH", "AUTO").upper()
+
+    if USE_TF in ("1", "ON", "YES", "AUTO") and USE_TORCH not in ("1", "ON", "YES"):
         import tensorflow as tf
 
         assert hasattr(tf, "__version__") and int(tf.__version__[0]) >= 2