Noufal Ibrahim wrote: > Hello everyone, > I've come across a situation which is somewhat confusing to me. > I googled for some details and came across another email thread on > this very list but couldn't really glean a solution out of it. > > I have a program (a compiled binary) for which I need to write a > wrapper (in python). The wrapper will construct some sane command line > defaults for this binary and then execute it while storing some > statistics like who launched it, where and when. > > Now this program will continuously print output (it's a parallel > version of make). It it receives a SIGINT (via a Ctrl-C), it will print > some statistics and go on with the build. If it receives a Ctrl-\ > (SIGQUIT I think), it will terminate. I want my wrapper to be able to > read the output of this program and print it while allowing these two > signals to be passed to it. > > My wrapper (let's call it wrapper.py) has something like this > > ------------------------------------------------------------------ > def createSignalDelegator(p): > def sighandler(signal,frame,pmake = p): > os.kill(pmake.pid,signal) > return sighandler > > pmake = subprocess.Popen(pmake_cmd, bufsize = 1, stdout = > subprocess.PIPE, stderr = subprocess.STDOUT) > > signal.signal(signal.SIGINT,createSignalDelegator(pmake)) > signal.signal(signal.SIGQUIT,createSignalDelegator(pmake)) > for op in pmake.stdout: > print "-- %s"%str(op).strip() > ------------------------------------------------------------------ > > I've substituted my actual binary with a simple python script that > continuously prints a string and which traps sigint and sigquit to > appear like the binary. It seems to be receiving the signals fine (since > I log it's activity into a separate file) but the problems I get are like so >
I'm not an expert on the subprocess module, but I've used it a bit and I'm referring to the docs as I write this. > 1. I don't see any output (from my 'build') on screen when I run my > wrapper. > Why do you think you should? You've asked subprocess to pipe its output you your parent process, I believe you would need to use the communicate() method to get the output generated by the subprocess. > 2. When I send a ^C to the wrapper, I don't see the output from the > build script. > Fix #1 first and then this should fall into place. > 3. I sometimes get a pipe error and the whole wrapper dies leaving the > other program running. > Exact error messages help a lot. :-) > I'd appreciate any insights into the problem. I'm not sure where to > start looking. > > Thanks. > > > _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
