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sockets,threads and interupts

Grant Edwards invalid at invalid.invalid
Tue Sep 4 14:11:12 EDT 2012 
On 2012-09-04, MRAB <python at mrabarnett.plus.com> wrote:
> On 04/09/2012 16:26, loial wrote:
>> I have threaded python script that uses sockets to monitor network
>> ports.
>>
>> I want to ensure that the socket is closed cleanly in all
>> circumstances. This includes if the script is killed or interupted in
>> some other way.
>>
>> As I understand it signal only works in the main thread, so how can I
>> trap interupts in my threaded class and always ensure I close the
>> socket? Using KeyboardInterupt does not seem to work.
>>
> You could wrap it in try...finally. The 'finally' clause is guaranteed
> to be run, so you can close the sockets there.
>
> However, if the script is just killed, then it won't get the chance
> to tidy up.

That depends on the signal used to "kill" the thread.

You can catch SIGTERM and SIGINT and clean up before exiting.

You can't catch SIGKILL, but sending a SIGKILL isn't considered polite
unless you've already tried SIGTERM/SIGINT and it didn't work.

-- 
Grant Edwards               grant.b.edwards        Yow! Are we on STRIKE yet?
                                  at               
                              gmail.com
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