Help with threads

Ruby
1

hi all,
i’m trying to do some automated tasks with threads.
Basically, my app is initialized with an input file, and an output path
and some processing is done on that.
I’m trying to automatically detect when the thread dies, so that it can
tell the parent class that this thread is complete.
Is there a nice way to do this without polling every thread? I seem to
recall something relating to the Rufus::Scheduler stuff being able to do
similar, but i can’t remember the name of that or where i found it. any
information would be great!

thanks,
ol.

2

On Mon, Jun 30, 2008 at 12:54 PM, Oliver F. [email protected]
wrote:

hi all,
i’m trying to do some automated tasks with threads.
Basically, my app is initialized with an input file, and an output path
and some processing is done on that.
I’m trying to automatically detect when the thread dies, so that it can
tell the parent class that this thread is complete.
Is there a nice way to do this without polling every thread? I seem to
recall something relating to the Rufus::Scheduler stuff being able to do
similar, but i can’t remember the name of that or where i found it. any
information would be great!

Hi Oliver,

Have you looked at the Monitor class and using MonitorMixin? I
believe your main thread could do a “wait_while” and your child
threads could do a “signal” when they’re done to notify the main
thread.

This is assuming you have multiple child threads. If there’s only
one, then doing a “join” would be easier.

I hope that helps,

Eric

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3

Hello Oliver,

I needed to do something similar than you once, but in my case I needed
to
wait until all the threads were finished.

I’ve just looped in the main thread while the Thread.list.size was
greater
than 1.

I hope this helps,

Guillermo

From:
Oliver F. [email protected]
To:
[email protected] (ruby-talk ML)
Date:
30.06.2008 19:00
Subject:
help with threads

hi all,
i’m trying to do some automated tasks with threads.
Basically, my app is initialized with an input file, and an output path
and some processing is done on that.
I’m trying to automatically detect when the thread dies, so that it can
tell the parent class that this thread is complete.
Is there a nice way to do this without polling every thread? I seem to
recall something relating to the Rufus::Scheduler stuff being able to do
similar, but i can’t remember the name of that or where i found it. any
information would be great!

thanks,
ol.

4

Oliver F. wrote:

hi all,
i’m trying to do some automated tasks with threads.
Basically, my app is initialized with an input file, and an output path
and some processing is done on that.
I’m trying to automatically detect when the thread dies, so that it can
tell the parent class that this thread is complete.
Is there a nice way to do this without polling every thread? I seem to
recall something relating to the Rufus::Scheduler stuff being able to do
similar, but i can’t remember the name of that or where i found it. any
information would be great!

A thread won’t die without reason. If the thread completes normally, you
can set a flag or set the thread’s result to something non-nil
(Thread.current[:some_key] = result) that you can check for. If it
terminates early due to an exception, you can either rescue that
exception or let it bubble out and terminate the thread, which will set
the thread’s value to the exception object.

To avoid constantly polling, you want some kind of synchronization
mechanism like those in the ‘thread’ library (Monitors, Semaphores,
etc).

  • Charlie