如何不断地将STDOUT发送到我的pythontcp服务器？

How to constantly send STDOUT to my python TCP server?(如何不断地将STDOUT发送到我的pythontcp服务器？)

问题描述

1. 我有一个使用套接字并将随机数回送到客户端的简单的Python回显服务器。
2. 我有另一个程序，它每隔2秒将值打印到标准输出。

如果它只是一个脚本，我可以像这样重定向‘stdout’|python script.py，并像这样在脚本中获取它data = sys.stdin.read()。但这是一台服务器，它不会像这样工作。

问题：如何编写这样的Python服务器，以便它可以侦听/获取Debian上的stdout的值，并进一步传递它们。我不是要求完整的代码。考虑到程序是一台服务器，这只是一些关于获得stdout的想法。

不断传来的值>stdout>server.py>进一步发送值

推荐答案

我认为您需要类似于Python subprocess的内容。在该示例中，将dmesg视为数字生成器，将grep作为套接字服务器；但是，您只需在套接字服务器中打开PIPE，而不会产生外壳命令。

假设您有两个进程，讲话者和服务器(在Python2.x中)...

talker.py

"""
Call as talker.py <INTEGER_DELAY>
"""

import time
import sys

assert sys.version_info < (3, 0, 0)

DELAY = int(sys.argv[1])
ii = 1
while True:
    sys.stdout.write("Talk every %i seconds, blabbed %i times
" % (DELAY, ii))
    sys.stdout.flush()
    ii += 1
    time.sleep(DELAY)

server.py

#!/usr/bin/env python

from subprocess import Popen, PIPE
from os import kill
import signal
import sys

assert sys.version_info < (3, 0, 0)

talkpipe = Popen(['python', 'talker.py', '3'],
    shell=False, stdout=PIPE)
try:
    while True:
        line = talkpipe.stdout.readline()
        print "SERVER HEARD", line.strip()
except KeyboardInterrupt:
    print "Killing child..."
    kill(talkpipe.pid, signal.SIGTERM)

使用./server.py运行此命令会产生...

[mpenning@Bucksnort tmp]$ python server.py
SERVER HEARD Talk every 3 seconds, blabbed 1 times
SERVER HEARD Talk every 3 seconds, blabbed 2 times
SERVER HEARD Talk every 3 seconds, blabbed 3 times
SERVER HEARD Talk every 3 seconds, blabbed 4 times
^CTraceback (most recent call last):
  File "talker.py", line 11, in <module>
    time.sleep(DELAY)
KeyboardInterrupt
Killing child...
[mpenning@Bucksnort tmp]$

这些脚本的(更强大的)Python3版本是...

talker.py

"""
talker.py: run talker.py with continuous stdout stream and control-C handling.

talker.py was written for Python3, but it should be fine under Python 2.X...
- To run under python 2.x, set `ENFORCE_PYTHON_3 = 0`

Execute with: 'python talker.py <DELAY_INTEGER>'
"""

import signal
import types
import time
import sys
import os

CATCH_CONTROL_C = 1
ENFORCE_PYTHON_3 = 1
BOUNDARY_CONDITIONS_SET = 0

def custom_signal_handler(signum, stackframe):
    assert isinstance(signum, int)
    assert isinstance(stackframe, types.FrameType)
    assert isinstance(BOUNDARY_CONDITIONS_SET, int) and BOUNDARY_CONDITIONS_SET >= 1

    print("---> custom_signal_handler() got signal: %s <---" % signum)
    if signum == 0:
        #  signal.SIG_DFL
        print(repr(stackframe))

    elif signum == 2:
        #  signal.SIGINT
        assert CATCH_CONTROL_C >= 1
        raise KeyboardInterrupt(repr(stackframe))

    else:
        raise NotImplementedError("Cannot handle signal %s" % signal.signum)

def set_boundary_conditions():

    global BOUNDARY_CONDITIONS_SET
    global DELAY_INTEGER

    assert isinstance(BOUNDARY_CONDITIONS_SET, int)
    assert BOUNDARY_CONDITIONS_SET <= 0

    if ENFORCE_PYTHON_3 == 1:
        assert tuple(sys.version_info) >= (3, 0, 0)

    # len(sys.argv) will be 1 if this script is imported into python
    # len(sys.argv) will be >= 2 if this script was called from CLI w/ args
    if len(sys.argv) == 1:
        # Called from an import statement...
        assert sys.argv[0] == ''
        DELAY_INTEGER = 1

    elif len(sys.argv) >= 2:
        # Called from the command-line... sys.argv[0] is the file name...
        assert sys.argv[0] == os.path.basename(__file__).strip()
        print("FOO", sys.argv[0])
        DELAY_INTEGER = int(sys.argv[1])
        assert DELAY_INTEGER > 0

    else:
        raise ValueError("DELAY_INTEGER was not specified correctly in the CLI")

    if CATCH_CONTROL_C >= 1:
        assert custom_signal_handler

        # Send control-C to the custom signal handler...
        signal.signal(signal.SIGINT, custom_signal_handler)
        print("    The current handler for signal.SIGINT is %s" % custom_signal_handler)

    else:
        assert signal.SIG_DFL
        # signal.SIGINT (control-C) is 2...
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        print("The current handler for signal.SIGINT is signal.SIG_DFL")

    BOUNDARY_CONDITIONS_SET = 1


def loop_talking_over_stdout():
    """
    Write messages to stdout with a variable delay...

    This function (loop_talking_over_stdout()) is a blocking call...
    """

    assert BOUNDARY_CONDITIONS_SET >= 1

    ii = 1
    while True:
        sys.stdout.write("Talk every %i seconds, blabbed %i times
" % (
            DELAY_INTEGER, ii))
        sys.stdout.flush()
        ii += 1
        time.sleep(DELAY_INTEGER)

if __name__=="__main__":
    print("running python %s" % list(sys.version_info))
    set_boundary_conditions()
    loop_talking_over_stdout()

server.py

#!/usr/bin/env python3

from subprocess import Popen, PIPE
from os import kill
import signal
import shlex
import sys
import os

assert sys.version_info >= (3, 0, 0,)

def custom_signal_handler(signum, stackframe):
    assert isinstance(signum, int)

    print("Got signal: %s" % signum)
    raise KeyboardInterrupt(repr(stackframe))

# Send control-C to the custom signal handler...
signal.signal(signal.SIGINT, custom_signal_handler)

TIMEOUT = 3

while True:
    filepath = os.sep.join((os.getcwd(), 'talker.py'))
    cmd = 'python3 %s %s' % (filepath, TIMEOUT)
    talkpipe = Popen(shlex.split(cmd), shell=False,
        stdin=PIPE, stdout=PIPE, stderr=PIPE)

    stdout = talkpipe.stdout
    stderr = talkpipe.stderr
    stdin = talkpipe.stdin


    for line_out in iter(stdout.readline, b''):
        print(b'out>>> ' + line_out.rstrip())

        for line_err in iter(stderr.readline, b''):
            print(b'err-->' + line_err)

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