我认为快速的代码段更能解释我的问题,所以请看一下:
from flask import Flask
from flask.ext.socketio import SocketIO
from threading import Thread
import subprocess
import threading
from eventlet.green.subprocess import Popen
app = Flask(__name__)
socketio = SocketIO(app)
def get_tasks_and_emit():
instance = Popen(["tasklist"], stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=1)
lines_iterator = iter(instance.stdout.readline, b"")
data = ""
for line in lines_iterator:
data += line.decode("utf8")
socketio.emit("loaded", data)
print("::: DEBUG - returned tasks with thread")
@app.route("/")
def index():
html = "<!DOCTYPE html>"
html += "<script src=https://code.jquery.com/jquery-2.2.0.min.js></script>"
html += "<script src=https://cdn.socket.io/socket.io-1.4.5.js></script>"
html += "<script>"
html += "var socket = io.connect(window.location.origin);"
html += "socket.on('loaded', function(data) {alert(data);});"
html += "function load_tasks_threaded() {$.get('/tasks_threaded');}"
html += "function load_tasks_nonthreaded() {$.get('/tasks');}"
html += "</script>"
html += "<button onclick='load_tasks_nonthreaded()'>Load Tasks</button>"
html += "<button onclick='load_tasks_threaded()'>Load Tasks (Threaded)</button>"
return html
@app.route("/tasks")
def tasks():
get_tasks_and_emit()
print("::: DEBUG - returned tasks without thread")
return ""
@app.route("/tasks_threaded")
def tasks_threaded():
threading.Thread(target=get_tasks_and_emit).start()
return ""
if __name__ == "__main__":
socketio.run(app, port=7000, debug=True)
我在Windows上使用eventlet运行此代码,如果我不使用eventlet,一切都很好(但当然由于werkzeug线程模式而慢得多)。 (我刚检查过,它也没有在Linux上工作)
我希望有人能指出我正确的方向。 (顺便说一下,我的Python版本是3.5.1)
答案 0 :(得分:3)
我发现了问题。显然你必须修补线程模块,所以我添加了
import eventlet
eventlet.monkey_patch(thread=True)
然后我也遇到了长时间运行程序的问题。我遇到了与StackOverflow帖子中的人一样的问题: Using Popen in a thread blocks every incoming Flask-SocketIO request
所以我添加了
eventlet.sleep()
到处理管道的for循环。
编辑:
正如temoto指出的那样,也可以使用eventlet.green
中的线程模块,如下所示:
from eventlet.green import threading