Python Flask 关闭事件处理程序

Question

我使用 Flask 作为 REST 端点，它将应用程序请求添加到队列中。然后队列被第二个线程消耗。

server.py

def get_application():
    global app
    app.debug = True
    app.queue = client.Agent()
    app.queue.start()                                                                                                                                                                                                                
    return app

@app.route("/api/v1/test/", methods=["POST"])
def test():
     if request.method == "POST":
        try:
           #add the request parameters to queue
           app.queue.add_to_queue(req)
        except Exception:
            return "All the parameters must be provided" , 400
     return "", 200

     return "Resource not found",404

client.py

class Agent(threading.Thread):

      def __init__(self):
          threading.Thread.__init__(self)
          self.active = True
          self.queue = Queue.Queue(0)


      def run(self):
           while self.active:
              req = self.queue.get()
              #do something


      def add_to_queue(self,request):
           self.queue.put(request)

flask 中是否有一个关闭事件处理程序，以便我可以在 flask 应用程序关闭时（例如重新启动 apache 服务时）干净地关闭使用者线程？

Answer 1

from flask import request

BASE_URL = "http://127.0.0.1:5000"
SHUTDOWN = "/shutdown"

def shutdown_server():
    func = request.environ.get('werkzeug.server.shutdown')
    if func is None:
        raise RuntimeError('Not running with the Werkzeug Server')
    func()

@app.route(SHUTDOWN, methods=['POST'])
def shutdown():
    shutdown_server()
    return 'Server shutting down...'

这里似乎提到了一种方法：- http://web.archive.org/web/20190706125149/http://flask.pocoo.org/snippets/67

Answer 2

没有 app.stop() 如果那是你正在寻找的，但是使用模块 atexit 你可以做类似的事情：

https://docs.python.org/2/library/atexit.html

考虑一下：

import atexit
#defining function to run on shutdown
def close_running_threads():
    for thread in the_threads:
        thread.join()
    print "Threads complete, ready to finish"
#Register the function to be called on exit
atexit.register(close_running_threads)
#start your process
app.run()

另外注意-atexit 如果您使用 Ctrl-C 强制关闭服务器，则不会调用。

为此还有另一个模块-signal。

https://docs.python.org/2/library/signal.html