Python生成命名管道并保持打开状态…意外行为

Question

我正在尝试模拟创建管道并保持其打开状态。在Bash中，我会mkfifo /tmp/myfifo; cat > /tmp/myfifo.

在Python中，我有：

import sys
import os
import string
import subprocess
import time
from multiprocessing import Process
from termSize import getTerminalSize
from redirect import RedirectStream

def viewer():
        path = "/tmp/myfifo"
        file = open(path, "w")
        subprocess.Popen(["cat"], stdout=file)

def base_menu(func):
    def  menu():
        python_path = sys.executable
        fifo_path = "/tmp/myfifo"
        called_function = func()
        path = called_function[0]
        menu_name = called_function[1]
        header = "Foobar YO"
        term = getTerminalSize()

        sys.stderr.write("\x1b[2J\x1b[H")
        print header.center(term, '*')
        print menu_name.center(term, '+')
        print "Please choose which option:"
        files = os.listdir(path)
        for i in files:
            print (str(files.index(i)+1)) + ") "\
                    + i.strip(".py") 
        while True:
            choice = raw_input("\nPlease Choose[ENTER for Main]: ")
            try:
                choice = int(choice)- 1
                with open(fifo_path, "w") as file:
                    with RedirectStream(file):
                        print(time.strftime("%H:%M:%S",\
                            time.localtime(time.time()))\
                             +" -------------------")
            except IndexError:
                print "error"

    return menu

def main_menu():
    header = "Foobar YO"
    menu_name = "Main Menu"
    term = getTerminalSize()

    sys.stderr.write("\x1b[2J\x1b[H")
    print header.center(term, '*')
    print menu_name.center(term, '+')
    print "Please choose which option:"

    menus = (
            servers_menu,
            database_menu,
            files_menu,
            networks_menu,
            dns_menu,
            blockstorage_menu,
            loadbalancers_menu
            )

    text = "1) Servers\n"\
            "2) Databases\n"\
            "3) Files\n"\
            "4) Networks\n"\
            "5) DNS\n"\
            "6) Block Storage\n"\
            "7) Load Balancers\n"\
            "Please Choose: "

    value = raw_input(text)
    return value, menus

@base_menu
def database_menu():
    path = "/home/work/cloud_databases/"
    menu_name = "Database Menu"
    return path, menu_name

@base_menu
def blockstorage_menu():
    path = "/home/work/cloud_blockstorage/"
    menu_name = "Block Storage Menu"
    return path, menu_name

@base_menu
def dns_menu():
    path = "/home/work/cloud_dns/"
    menu_name = "DNS Menu"
    return path, menu_name

@base_menu
def loadbalancers_menu():
    path = "/home/work/cloud_loadbalancers/"
    menu_name = "Load Balancers Menu"
    return path, menu_name

@base_menu
def networks_menu():
    path = "/home/work/cloud_networks/"
    menu_name = "Networks Menu"
    return path, menu_name

@base_menu
def files_menu():
    path = "/home/work/cloudfiles/"
    menu_name = "Files Menu"
    return path, menu_name

@base_menu
def servers_menu():
    path = "/home/work/cloudservers/"
    menu_name = "Servers Menu"
    return path, menu_name

def main():
    p1 = Process(target=viewer)
    p1.start()
    while True:
        value, menus = main_menu()
        try: 
            value = int(value)-1
            menus[value]()
        except ValueError:
            print "oops-ee"
        except IndexError:
            print "oops-ee"

main()

现在，我使用cat<；/tmp/myfifo运行另一个shell会话，使其保持读取状态。在

问题是，当试图使这个函数viewer（）与main中的所有其他东西并行运行时，我没有得到预期的/相同的行为，如果我手动在shell中创建、打开并读取管道。在