gevent.hub.LoopExit: ('This operation would block forever',

使用pycharm运行flask的monkey patch（猴子补丁）时，调试和运行代码报错：

Exception happened during processing of request from ('127.0.0.1', 53647)
Traceback (most recent call last):
  File "C:\Python36\lib\socketserver.py", line 639, in process_request_thread
    self.finish_request(request, client_address)
  File "C:\Python36\lib\socketserver.py", line 361, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "C:\Python36\lib\socketserver.py", line 696, in __init__
    self.handle()
  File "C:\Python36\lib\site-packages\werkzeug\serving.py", line 325, in handle
    rv = BaseHTTPRequestHandler.handle(self)
  File "C:\Python36\lib\http\server.py", line 418, in handle
    self.handle_one_request()
  File "C:\Python36\lib\site-packages\werkzeug\serving.py", line 356, in handle_one_request
    self.raw_requestline = self.rfile.readline()
  File "C:\Python36\lib\socket.py", line 586, in readinto
    return self._sock.recv_into(b)
  File "C:\Python36\lib\site-packages\gevent\_socket3.py", line 384, in recv_into
    self._wait(self._read_event)
  File "C:\Python36\lib\site-packages\gevent\_socket3.py", line 156, in _wait
    self.hub.wait(watcher)
  File "C:\Python36\lib\site-packages\gevent\hub.py", line 651, in wait
    result = waiter.get()
  File "C:\Python36\lib\site-packages\gevent\hub.py", line 898, in get
    return self.hub.switch()
  File "C:\Python36\lib\site-packages\gevent\hub.py", line 630, in switch
    return RawGreenlet.switch(self)
gevent.hub.LoopExit: ('This operation would block forever', )
----------------------------------------

 

代码实例：

from flask import Flask
from gevent import monkey
from gevent import pywsgi
import pymysql

monkey.patch_all(thread=False)  # 使用猴子补丁，将真个应用转变为协程的方式运行，提高并发性能,thread=False使多线程不阻塞
app = Flask(__name__)

@app.route('/t')
def hello_world():
    return 'Hello World!'

if __name__ == '__main__':
    #app.run()
    server = pywsgi.WSGIServer(("127.0.0.1", 5000), app)  # 使用WSGIServer将app应用封装成wsgi服务
    server.serve_forever()

原因分析:

查看代码没有配置和编辑错误

查看flask启动命令打印：

C:\Python36\python.exe -m flask run
 * Serving Flask app "main.py"
 * Environment: development
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

发现启动的命令不对

根因分析：

配置运行的命令不对，这是默认flask启动的配置

解决方式：

修改flask启动环境及命令配置

如上为正常启动右键格式，打印的执行命令应该如下：