I have the following code with FastApi and Uvicorn for ASGI sever implementation. It's supposed to take an uploaded image via post request and classify it with a model before returning a response. The error seems related to Uvicorn but I am at a loss. Any help would be much appreciated. Has anyone seen an error like this before? Here is the code:
import uvicorn
from fastapi import FastAPI, File, UploadFile
import sys
from PIL import Image
from io import BytesIO
import numpy as np
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
import matplotlib.pyplot as plt
from tensorflow.keras.preprocessing import image
import PIL
import sys
from cv2 import cv2
from scipy import misc
import os
import shutil
from pathlib import Path
from tempfile import NamedTemporaryFile
from typing import Callable
app = FastAPI()
model = keras.models.load_model('best_model6.h5')
input_shape = (180, 180)
@app.post('/api/predict')
async def predict_image(file: UploadFile = File(...)):
suffix = Path(file.filename).suffix
with NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
shutil.copyfileobj(file.file, tmp)
tmp_path = Path(tmp.name)
img = keras.preprocessing.image.load_img(
tmp_path, target_size=input_shape
)
img_array = image.img_to_array(img)
img_array = tf.expand_dims(img_array, 0) # Create batch axis
predictions = model.predict(img_array)
score = predictions[0]
file.file.close()
tmp_path.unlink()
return score
if __name__ == "__main__":
uvicorn.run(app, port=8080, host='0.0.0.0', debug=True)
The error is:
ValueError: [TypeError('cannot convert dictionary update sequence element #0 to a sequence'), TypeError('vars() argument must have __dict__ attribute')]
And the whole traceback:
Traceback (most recent call last):
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/uvicorn/protocols/http/h11_impl.py", line 373, in run_asgi
result = await app(self.scope, self.receive, self.send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
return await self.app(scope, receive, send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/uvicorn/middleware/debug.py", line 96, in __call__
raise exc from None
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/uvicorn/middleware/debug.py", line 93, in __call__
await self.app(scope, receive, inner_send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/fastapi/applications.py", line 208, in __call__
await super().__call__(scope, receive, send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/applications.py", line 112, in __call__
await self.middleware_stack(scope, receive, send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/middleware/errors.py", line 181, in __call__
raise exc
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/middleware/errors.py", line 159, in __call__
await self.app(scope, receive, _send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/exceptions.py", line 82, in __call__
raise exc
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/exceptions.py", line 71, in __call__
await self.app(scope, receive, sender)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/routing.py", line 656, in __call__
await route.handle(scope, receive, send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/routing.py", line 259, in handle
await self.app(scope, receive, send)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/starlette/routing.py", line 61, in app
response = await func(request)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/fastapi/routing.py", line 234, in app
response_data = await serialize_response(
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/fastapi/routing.py", line 148, in serialize_response
return jsonable_encoder(response_content)
File "/Users/.../Desktop/project/venv/lib/python3.9/site-packages/fastapi/encoders.py", line 144, in jsonable_encoder
raise ValueError(errors)
ValueError: [TypeError('cannot convert dictionary update sequence element #0 to a sequence'), TypeError('vars() argument must have __dict__ attribute')]
CodePudding user response:
The return of predit function from Keras Model is a Numpy array(s) of predictions (see here) and each prediction is a numpy array as well.
But FastApi use jsonable_encoder in a response (see here) and numpy array is not acceptable. You should convert to list(score.tolist()
), for example, to return the prediction scores. In the same link, you will see that is possible return a response directly without use jsonable_encoder
I hope I have helped you. Good luck