Python多处理将子进程的stdout重定向到Tkinter Text

我正在尝试使用Tkinter GUI来启动子进程并将其stdout / stderr输出显示到Text小部件.最初,我认为通过设置“sys.stdout = text_widget”可以很容易地将sys.stdout重定向到Text小部件,但似乎没有.它出现错误：“文本实例没有属性’flush’”.

我在网上查了一下,得到了一些解决方案,比如使用Queue与子进程进行通信.但是,由于我的特殊要求,它们都不适合我的情况：

>最好通过“multiprocessing.Process”启动子进程,因为使用共享变量会更容易,这使得子进程解决方案可用.
>子进程的代码已经存在,里面有很多“打印”,所以我不想将它们修改为“Queue.put()”之类的东西.

在这种情况下,任何人都可以找到一个获得“multiprocessing.Process”的“打印”输出并显示到Tkinter文本的解决方案吗？非常感谢！

我的案例的示例代码如下：

import sys
import time
from multiprocessing import Process
from Tkinter import *

def test_child():
    print 'child running'

def test_parent():
    print 'parent running'
    time.sleep(0.5)
    Process(target=test_child).start()

def set_txt(msg):
    gui_txt.insert(END, str(msg))
    gui_txt.see(END)

if __name__ == '__main__':
    gui_root = Tk()
    gui_txt = Text(gui_root)
    gui_txt.pack()
    gui_btn = Button(gui_root, text='Test', command=test_parent)
    gui_btn.pack()

    gui_txt.write = set_txt
    sys.stdout = gui_txt

    gui_root.mainloop()

解决方法:

仍然可以使用队列而不必删除所有打印语句.您可以使用依赖于进程的stdout重定向来执行此操作.下面的解决方案使用Queue子类来模仿stdout.然后,该队列由一个线程监视,该线程查找被泵入文本小部件的新文本.

import sys
import time
from multiprocessing import Process
from multiprocessing.queues import Queue
from threading import Thread
from Tkinter import *

# This function takes the text widget and a queue as inputs.
# It functions by waiting on new data entering the queue, when it 
# finds new data it will insert it into the text widget 
def text_catcher(text_widget,queue):
    while True:
        text_widget.insert(END, queue.get())

# This is a Queue that behaves like stdout
class StdoutQueue(Queue):
    def __init__(self,*args,**kwargs):
        Queue.__init__(self,*args,**kwargs)

    def write(self,msg):
        self.put(msg)

    def flush(self):
        sys.__stdout__.flush()


def test_child(q):
    # This line only redirects stdout inside the current process 
    sys.stdout = q
    # or sys.stdout = sys.__stdout__ if you want to print the child to the terminal
    print 'child running'

def test_parent(q):
    # Again this only redirects inside the current (main) process
    # commenting this like out will cause only the child to write to the widget 
    sys.stdout = q                                                                                                                                                                                                                                                         
    print 'parent running'
    time.sleep(0.5)
    Process(target=test_child,args=(q,)).start()

if __name__ == '__main__':
    gui_root = Tk()
    gui_txt = Text(gui_root)
    gui_txt.pack()
    q = StdoutQueue()
    gui_btn = Button(gui_root, text='Test', command=lambda:test_parent(q),)
    gui_btn.pack()

    # Instantiate and start the text monitor
    monitor = Thread(target=text_catcher,args=(gui_txt,q))
    monitor.daemon = True
    monitor.start()

    gui_root.mainloop()