[英]python unable to detach process when teed. How to span background process and exit with no wait?
我从一个简单的测试用例开始:
cat foo2.py
#!/usr/bin/python
import subprocess, sys, os
def alert():
subprocess.Popen ("xterm &", shell=True, stdin=None, stdout=None, stderr=None, close_fds=True)
if __name__ == "__main__":
print "hello"
alert ()
os._exit (0)
当我在命令行上定期运行该代码时,它可以工作:
./foo2.py
返回unix提示符,xterm在后台运行。
但是,当我用tee运行该代码时
./foo2.py | tee my.log
在关闭xterm之前,我没有得到unix提示符。
如何让python脚本退出,但是让xterm在后台运行?
我已经看到: Python产生子子进程,分离和退出以及那里提到的activestate配方。 我已经使用该代码创建了一个简单的测试用例,它只是在后台打开一个xterm:
cat foo.py
#!/usr/bin/python
import subprocess, sys, os
def alert():
subprocess.Popen ("xterm &", shell=True, stdin=None, stdout=None, stderr=None)
def createDaemon():
"""Detach a process from the controlling terminal and run it in the
background as a daemon.
"""
try:
pid = os.fork() # Fork a first child.
except OSError, e:
raise Exception, "%s [%d]" % (e.strerror, e.errno)
if (pid == 0): # The first child.
os.setsid()
try:
pid = os.fork() # Fork a second child.
except OSError, e:
raise Exception, "%s [%d]" % (e.strerror, e.errno)
if (pid == 0): # The second child.
alert ()
else:
os._exit(0) # Exit parent (the first child) of the second child.
else:
os._exit(0) # Exit parent of the first child.
# Close all open file descriptors. This prevents the child from keeping
import resource # Resource usage information.
maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
if (maxfd == resource.RLIM_INFINITY):
maxfd = 1024
# Iterate through and close all file descriptors.
for fd in range(0, maxfd):
try:
os.close(fd)
except OSError: # ERROR, fd wasn't open to begin with (ignored)
pass
os.open(REDIRECT_TO, os.O_RDWR) # standard input (0)
os.dup2(0, 1) # standard output (1)
os.dup2(0, 2) # standard error (2)
return(0)
if __name__ == "__main__":
print "hello"
retCode = createDaemon()
sys.exit (0)
当我在命令行上定期运行该代码时,它可以工作:
./foo.py
返回unix提示符,xterm在后台运行。
但是,当我用tee运行该代码时
./foo.py | tee my.log
在关闭xterm之前,我没有得到unix提示符。
如何让python脚本退出,但是让xterm在后台运行?
运行nohup xterm &
(以便进程解耦)
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