Re: [Kimchi-devel] [PATCH V1] add a synchronous function with timeout to execute command

On 2014年01月10日 09:00, shaohef(a)linux.vnet.ibm.com wrote: > From: ShaoHe Feng <shaohef(a)linux.vnet.ibm.com&gt; > > We need a common function to execute shell command. > We also need timeout when execute shell command. > > A threading.Timer is used to send signal.SIGKILL to kill the command > when timeout. > > Signed-off-by: Royce Lv <lvroyce(a)linux.vnet.ibm.com&gt; > Signed-off-by: ShaoHe Feng <shaohef(a)linux.vnet.ibm.com&gt; > --- > src/kimchi/utils.py | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/src/kimchi/utils.py b/src/kimchi/utils.py > index af245c6..94097ad 100644 > --- a/src/kimchi/utils.py > +++ b/src/kimchi/utils.py > @@ -23,6 +23,7 @@ > > import cherrypy > import os > +import subprocess > import urllib2 > > > @@ -30,6 +31,7 @@ from cherrypy.lib.reprconf import Parser > > > from kimchi import config > +from threading import Timer > > > kimchi_log = cherrypy.log.error_log > @@ -96,3 +98,40 @@ def check_url_path(path): > return False > > return True > + > + > +def run_command(cmd, timeout=None): > + def kill_proc(proc, timeout_flag): > + timeout_flag[0] = True > + proc.kill() > + > + proc = None > + timer = None > + timeout_flag = [False] > + > + try: > + proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, > + stderr=subprocess.PIPE) > + if timeout is not None: > + timer = Timer(timeout, kill_proc, [proc, timeout_flag]) > + timer.start() I like the idea of using timer, I think the only thing we need to take care is check timeout happens and report a specific error. Or when we kill the proc and it is blocked, the proc.communicate() error will not be 'timeout happens' > + > + out, error = proc.communicate() > + kimchi_log.debug("Run command '%s'", " ".join(cmd)) > + > + if out or error: > + kimchi_log.debug("out:\n %s\nerror:\n %s", out, error) > + > + return out, error, proc.returncode, timeout_flag[0] > + except Exception as e: > + msg = "Failed to run command: %s." % " ".join(cmd) > + msg = msg if proc is None else msg + "\n error code: %s." > + kimchi_log.error("%s\n %s", msg, e) > + > + if proc: > + return out, error, proc.returncode, timeout_flag[0] > + else: > + return None, None, None, timeout_flag[0] > + finally: > + if timer and not timeout_flag[0]: > + timer.cancel()