TerryP wrote:
On Oct 15, 7:42 pm, Jeremy <jlcon...@gmail.com> wrote:
I need to write a Python script that will call some command line
programs (using os.system). I will have many such calls, but I want
to control when the calls are made. I won't know in advance how long
each program will run and I don't want to have 10 programs running
when I only have one or two processors. I want to run one at a time
(or two if I have two processors), wait until it's finished, and then
call the next one.
How can I use Python to schedule these commands?
Thanks,
Jeremy
External programs are not system calls; external programs are invoked
through system calls; for example system() is a function call which
when implemented under UNIX systems invokes some form of fork() and
exec(), and likely spawn() under Windows NT.
If you want simple sequenceal execution of external programs, use a
suitable blocking function to execute them (like system) combined with
a simple loop over the sequence of commands to run.
for prog in ['cmd1', 'cmd2', 'cmd3']:
os.system(prog)
blah.
For anything more detailed (or complex) in response, try being more
detailed yourself ;).
You could use multithreading: put the commands into a queue; start the
same number of worker threads as there are processors; each worker
thread repeatedly gets a command from the queue and then runs it using
os.system(); if a worker thread finds that the queue is empty when it
tries to get a command, then it terminates.
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