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POPython processes stops responding to SIGTERM / SIGINT after being restarted
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copied!<p>I'm having a weird problem with some python processes running using a watchdog process.</p> <p>The watchdog process is written in python and is the parent, and has a function called <em>start_child(name)</em> which uses <em>subprocess.Popen</em> to open the child process. The Popen object is recorded so that the watchdog can monitor the process using <strong>poll()</strong> and eventually end it with <strong>terminate()</strong> when needed. If the child dies unexpectedly, the watchdog calls <em>start_child(name)</em> again and records the new Popen object.</p> <p>There are 7 child processes, all of which are also python. If I run any of the children manually, I can send SIGTERM or SIGINT using <em>kill</em> and get the results I expect (the process ends).</p> <p>However, when run from the watchdog process, the child will only end after the <strong>FIRST</strong> signal. When the watchdog restarts the child, the new child process no longer responds to SIGTERM or SIGINT. I have no idea what is causing this.</p> <p><strong>watchdog.py</strong></p> <pre><code>class watchdog: # <snip> various init stuff def start(self): self.running = true kids = ['app1', 'app2', 'app3', 'app4', 'app5', 'app6', 'app7'] self.processes = {} for kid in kids: self.start_child(kid) self.thread = threading.Thread(target=self._monitor) self.thread.start() while self.running: time.sleep(10) def start_child(self, name): try: proc = subprocess.Popen(name) self.processes[name] = proc except: print "oh no" else: print "started child ok" def _monitor(self): while self.running: time.sleep(1) if self.running: for kid, proc in self.processes.iteritems(): if proc.poll() is not None: # process ended self.start_child(kid) </code></pre> <p>So what happens is <em>watchdog.start()</em> launches all 7 processes, and if I send any process SIGTERM, it ends, and the monitor thread starts it again. However, if I then send the new process SIGTERM, it ignores it.</p> <p>I should be able to keep sending kill -15 to the restarted processes over and over again. Why do they ignore it after being restarted?</p>

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