number of threads in flask

Question

i just learn about flask and requests. i want to get the number of working threads when i post request to the server. and i want to measure the time spent of the working threads. so this is my server and my client code:

server.py

from flask import Flask
from flask import request
import time 
from flaskthreads import AppContextThread

app = Flask(__name__)

@app.route("/", methods = ['GET', 'POST'])

def home():
    timeout = time.time() + 10   # 5 minutes from now

    while True:
        test = 0
        if test ==5 or time.time() > timeout:
            break 

    return 'Hello', 200

def main():
    app.run(host='0.0.0.0', threaded = True, debug = True)


if __name__ == "__main__":
    main()

client.py

import os
import requests
import glob
import time 
import base64


url = 'http://0.0.0.0:5000/'


def load_data():

    os.chdir('./500_mb')
    for image in glob.glob('*.jpg'):
        with open(image, 'rb') as imageFile:
            # image_s = base64.b64encode(imageFile.read())
            image_s = {'file_image':open(image, 'rb')}

    return image_s

def send_data():

    start = time.time()
    r = requests.post(url, files = load_data())
    end = time.time()

    print('client 1: {} ms'.format((end - start)*1000))



if __name__ == "__main__":
    send_data()

how do i know the number of working threads ? i just add threaded = True on the server. i've been searching the answer and none of them answer my question. thanks in advance !

Answer 1

首先，通常的免责声明：这几乎无关紧要，因为您可以在实际移动到部署服务器时指定这一点。

然而，我自己很好奇，所以我决定追溯。

起点是在app.run()所以让我们看看它的作用：

def run_command(
    info, host, port, reload, debugger, eager_loading, with_threads, cert, extra_files
):

...

from werkzeug.serving import run_simple

    run_simple(
        host,
        port,
        app,
        use_reloader=reload,
        use_debugger=debugger,
        threaded=with_threads,
        ssl_context=cert,
        extra_files=extra_files,
    )

因此，下一个港口呼叫外是werkzeug.serving有run_simple。

从这里开始，您将对模块感到震惊：

1. 首先你会看到这使用 make_server
2. make_server 发射 ThreadedWSGIServer
3. ThreadedWSGIServer 使用ThreadingMixIn我们发现它只是ThreadingMixIn = socketserver.ThreadingMixIn

所以现在，我们知道我们需要去socketserver. 我们可以从源代码中看到以下内容：

class ThreadingMixIn:
    """Mix-in class to handle each request in a new thread."""

    ...

    def process_request(self, request, client_address):
        """Start a new thread to process the request."""
        t = threading.Thread(target = self.process_request_thread,
                             args = (request, client_address))
        t.daemon = self.daemon_threads
        if not t.daemon and self.block_on_close:
            if self._threads is None:
                self._threads = []
            self._threads.append(t)
        t.start()

因此，答案是它在每个请求上启动一个新线程。如果不出意外，这是跟踪代码路径的一个有趣的练习。