heroku - 使用 Anaconda 和 OpenCV 将 Docker 应用程序部署到 Heroku 时出现 "Could not find a version that satisfies the requirement cv2==1.0"

Question

我正在尝试将一个支持 Conda 的简单 Python 应用程序部署到 Heroku。

我可以毫无问题地将这个简单示例部署到 Heroku: https://github.com/heroku-examples/python-miniconda

但是当我添加 cv2 导入时它不再起作用了:

原始 app.py 文件:

from flask import Flask, jsonify
from sklearn import datasets, svm

app = Flask(__name__)

# Load Dataset from scikit-learn.
digits = datasets.load_digits()

@app.route('/')
def hello():
    clf = svm.SVC(gamma=0.001, C=100.)
    clf.fit(digits.data[:-1], digits.target[:-1])
    prediction = clf.predict(digits.data[-1:])

    return jsonify({'prediction': repr(prediction)})

if __name__ == '__main__':
    app.run(host='0.0.0.0')

修改后的 app.py 文件:

from flask import Flask, jsonify, render_template, request, redirect, url_for, send_from_directory
from sklearn import datasets, svm
import os
import json
import requests

# browser the file that the user just uploaded
from werkzeug import secure_filename
from keras.models import Sequential
from keras.layers.core import Flatten, Dense, Dropout
from keras.layers.convolutional import Convolution2D, MaxPooling2D, ZeroPadding2D
from keras.optimizers import SGD
from keras.applications.resnet50 import preprocess_input, decode_predictions
from keras import applications
import cv2, numpy as np

app = Flask(__name__)

# These are the extension that we are accepting to be uploaded
app.config['ALLOWED_EXTENSIONS'] = set(['png', 'jpg', 'jpeg', 'gif'])

# For a given file, return whether it's an allowed type or not
def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1] in app.config['ALLOWED_EXTENSIONS']

@app.route('/')
def hello_world():
    return 'Hello World!'

# Route that will process the file upload
@app.route('/upload', methods=['POST'])
def upload():
    # Get the name of the uploaded file
    file = request.files['file']
    # Check if the file is one of the allowed types/extensions
    if file and allowed_file(file.filename):
        # Make the filename safe, remove unsupported chars
        # filename = secure_filename(file.filename)
        # Move the file form the temporal folder to
        # the upload folder we setup
        # file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
        # Redirect the user to the uploaded_file route, which
        # will basicaly show on the browser the uploaded file
        file.save(file.filename)
        im = cv2.resize(cv2.imread(file.filename), (224, 224)).astype(np.float32)
        im[:,:,0] -= 103.939
        im[:,:,1] -= 116.779
        im[:,:,2] -= 123.68
        im = im.transpose((2,0,1))
        im = np.expand_dims(im, axis=0)
        out = model.predict(im)
        decoded = decode_predictions(out, top=3)[0]
        print('Predicted:', decoded)
        return str(decoded)

if __name__ == '__main__':
    # Test pretrained model
    model = applications.VGG19(include_top=True, weights='imagenet')
    app.run()

将此修改后的应用程序推送到 Heroku 时，我会收到此错误:

Could not find a version that satisfies the requirement cv2==1.0 (from -r /tmp/requirements.txt (line 10)) (from versions: )
No matching distribution found for cv2==1.0 (from -r /tmp/requirements.txt (line 10))
The command '/bin/sh -c pip install -qr /tmp/requirements.txt' returned a non-zero code: 1
 !    Error: docker build exited with 1

所以看起来 Docker 容器上缺少 cv2？我在示例项目的 Dockerfile 模板中添加了这一行“RUN conda install -c conda-forge opencv”，但它没有帮助:

FROM heroku/miniconda

# Grab requirements.txt.
ADD ./webapp/requirements.txt /tmp/requirements.txt

# Install dependencies
RUN pip install -qr /tmp/requirements.txt

# Add our code
ADD ./webapp /opt/webapp/
WORKDIR /opt/webapp

RUN conda install scikit-learn
RUN conda install -c conda-forge opencv

CMD gunicorn --bind 0.0.0.0:$PORT wsgi=

有什么帮助吗？

Answer 1

您看到的错误与以下事实有关:pip 无法安装 pypi 索引中列为 cv2 且版本为 1.0 的 pip 包。显然，该包描述是 "My Blog Distribution Utilities" 并且 https://pypi.python.org/simple/cv2/ 处没有文件。 ，这就是为什么您会看到类似于以下内容的错误:

(test) ubuntu@condaexpts:~$ pip install cv2==1.0
Collecting cv2==1.0
  Could not find a version that satisfies the requirement cv2==1.0 (from versions: )
No matching distribution found for cv2==1.0

很明显这不是您想要的包。所以请从文件 requirements.txt

中删除 cv2==1.0

您真正需要的是 opencv 的 conda 包，您应该可以从中获得:

RUN conda install -yc conda-forge opencv