Re: does IO.read block?


One problem that could hit you is that you might not get the
concurrency right: you need to make sure that stderr and stdout are
read concurrently (if there can be output on both) because if the pipe
on one of them fills up your child process is blocked. Maybe your
issue lies in that area.

I have set STDOUT.sync = true Is that enough? It should be, because I
don't have any output originating from the child processes or any child
threads, only the parent/calling thread. But I've been wrong before...

Though I think I have narrowed the problem _very_ slightly. The
thread/process pair that blocks indefinitely blocks on the
read_end.read() call. Which is weird and annoying. My next task will
be to set up some logging to figure out if there should have been an
exception to chuck down the pipe. (In my test case I have a random
amount of jobs, in which every second one raises an exception)

Thanks a lot for your help! It's certainly possible that this is going
to be my "Stupidly Difficult Bug When I Was Near The Beginning Of My
First Programming Job" that everyone seems to have.

Michael

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