Catching thread exceptions

Discussion in 'Ruby' started by Steve Tuckner, Aug 8, 2003.

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    Recently I was helping a colleague who was new to Ruby with a program
    that was using threads. It seemed to him that for some reason that some
    of the thread's were not running. First he tried adding sleeps to the
    main thread to "give time" to the other threads to run, but this didn't
    work. It turns out that by joining the threads in question, that there
    were errors in the program that were throwing exceptions that killed the
    thread -- SILENTLY.

    I don't know if there is a better way to do this, but this is the
    solution we came up with to print out any exceptions that occur in a
    thread (uncaught) and exit the program.

    require "thread"

    class MyThread < Thread
    def initialize(*args, &block)
    super(*args) do
    begin
    block.call
    rescue Exception => e
    $stderr.print "Exception occured: #{e.message} at " +
    e.backtrace.join("\n")
    exit! 1
    end
    end
    end
    end

    Is there a better way?

    Steve Tuckner

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    <DIV><FONT face=3DArial size=3D2><SPAN =
    class=3D009342117-08082003>Recently I was=20
    helping a colleague who was new to Ruby with a program that was using =
    threads.=20
    It seemed to him that for some reason that some of&nbsp;the thread's =
    were not=20
    running. First he tried adding sleeps to the main thread to "give time" =
    to the=20
    other threads to run, but this didn't work. It turns out that by =
    joining the=20
    threads in question, that there were errors in the program that were =
    throwing=20
    exceptions that killed the thread -- SILENTLY.</SPAN></FONT></DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN=20
    class=3D009342117-08082003></SPAN></FONT>&nbsp;</DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN class=3D009342117-08082003>I =
    don't know if=20
    there is a better way to do this, but this is the solution we came up =
    with to=20
    print out any exceptions that occur in a thread (uncaught) and exit the =

    program.</SPAN></FONT></DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN=20
    class=3D009342117-08082003></SPAN></FONT>&nbsp;</DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN =
    class=3D009342117-08082003>require=20
    "thread"</SPAN></FONT></DIV>
    <DIV>&nbsp;</DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN class=3D009342117-08082003>class =
    MyThread &lt;=20
    Thread<BR>&nbsp;def initialize(*args, =
    &amp;block)<BR>&nbsp;&nbsp;super(*args)=20
    do<BR>&nbsp;&nbsp;&nbsp;begin<BR>&nbsp;&nbsp;&nbsp;&nbsp;block.call<BR>&=
    nbsp;&nbsp;&nbsp;rescue=20
    Exception =3D&gt; e<BR>&nbsp;&nbsp;&nbsp;&nbsp;$stderr.print "Exception =
    occured:=20
    #{e.message} at " + =
    e.backtrace.join("\n")<BR>&nbsp;&nbsp;&nbsp;&nbsp;exit!=20
    1<BR>&nbsp;&nbsp;&nbsp;end<BR>&nbsp;&nbsp;end<BR>&nbsp;end<BR>end</SPAN>=
    </FONT></DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN=20
    class=3D009342117-08082003></SPAN></FONT>&nbsp;</DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN class=3D009342117-08082003>Is =
    there a better=20
    way?</SPAN></FONT></DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN=20
    class=3D009342117-08082003></SPAN></FONT>&nbsp;</DIV>
    <DIV><FONT face=3DArial size=3D2><SPAN class=3D009342117-08082003>Steve =

    Tuckner</SPAN></FONT></DIV></BODY></HTML>

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    Steve Tuckner, Aug 8, 2003
    #1
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  2. Steve Tuckner

    ts Guest

    S> Is there a better way?

    Thread.abort_on_exception = true

    svg% ruby -e 'Thread.new { raise "aa" }; p "after"'
    "after"
    svg%

    svg% ruby -e 'Thread.abort_on_exception = true; Thread.new { raise "aa" }; p "after"'
    -e:1: aa (RuntimeError)
    from -e:1:in `initialize'
    from -e:1:in `new'
    from -e:1
    svg%


    Guy Decoux
     
    ts, Aug 8, 2003
    #2
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  3. Brian Candler, Aug 8, 2003
    #3
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