log4perl-devel

[log4perl-devel] signal handling and log4perl

[Seth D. <log...@se...>]

Hello,

What I would like to do is prevent Log4perl from setting %SIG and I
would like to be the one to tell Log4perl when to reload the
configuration.  I do not want to use time-based delays if at all
possible.  So I want my code to do the signal handling and then notify
Log4perl to check its configuration.

The reason for this is that I have a number of existing programs that
use Log4perl for most logging, but some very specific logging does
not use Log4perl.  I need to be able to use a single signal to tell
both Log4perl and the other log code to check its configuration and/or
rewrite the log file for log rotation. 

Is this possible?  Looking at the code in Config/Watch.pm, Config.pm,
and Logger.pm it looks difficult.  Maybe there is a better way?

Thank you.

-- 
seth /\ sethdaniel.org

Re: [log4perl-devel] signal handling and log4perl

[Mike S. <m...@pe...>]

On Fri, 8 May 2009, Seth Daniel wrote:

> The reason for this is that I have a number of existing programs that
> use Log4perl for most logging, but some very specific logging does not
> use Log4perl.  I need to be able to use a single signal to tell both
> Log4perl and the other log code to check its configuration and/or
> rewrite the log file for log rotation.

You could use something like

     $SIG{USR2} = sub {
         kill 'USR1', $$;
         # ... now trigger your other logging system ...
     };

     Log::Log4perl->init_and_watch("l4p.conf", 'USR1');

which uses a user-defined signal handler listening to USR2. You can
add whatever other logic you need to it. When triggered, it also forwards
the signal to Log4perl's signal handler, which listens to USR1.

Good enough?

-- Mike

Mike Schilli
m...@pe...

Re: [log4perl-devel] signal handling and log4perl

[Seth D. <log...@se...>]

On Sat, May 09, 2009 at 12:12:28AM -0700, Mike Schilli wrote:
> On Fri, 8 May 2009, Seth Daniel wrote:
>
>> The reason for this is that I have a number of existing programs that
>> use Log4perl for most logging, but some very specific logging does not
>> use Log4perl.  I need to be able to use a single signal to tell both
>> Log4perl and the other log code to check its configuration and/or
>> rewrite the log file for log rotation.
>
> You could use something like
>
>     $SIG{USR2} = sub {
>         kill 'USR1', $$;
>         # ... now trigger your other logging system ...
>     };
>
>     Log::Log4perl->init_and_watch("l4p.conf", 'USR1');
>
> which uses a user-defined signal handler listening to USR2. You can
> add whatever other logic you need to it. When triggered, it also forwards
> the signal to Log4perl's signal handler, which listens to USR1.
>
> Good enough?


I was hoping for a solution that didn't burn two signals.  I'm already
using the most obvious signals: HUP, USR1, USR2, KILL, QUIT, etc...  so
I'm not exactly overflowing with extra signals. :o)

-- 
seth /\ sethdaniel.org

Re: [log4perl-devel] signal handling and log4perl

[Mike S. <m...@pe...>]

On Sat, 9 May 2009, Seth Daniel wrote:

> I was hoping for a solution that didn't burn two signals.  I'm already
> using the most obvious signals: HUP, USR1, USR2, KILL, QUIT, etc...
> so I'm not exactly overflowing with extra signals. :o)

I see ... in the next version of Log4perl (1.23), you'll be able to call

     Log::Log4perl::Config->watcher->force_next_check();

instead of using a signal:

     http://github.com/mschilli/log4perl/commit/6c8609f1ba064d3f781769cb9e1b45638f3daa75

(will probably go out soon).

-- Mike

Mike Schilli
m...@pe...

Re: [log4perl-devel] signal handling and log4perl

[Seth D. <log...@se...>]

On Sat, May 09, 2009 at 04:51:47PM -0700, Mike Schilli wrote:
> On Sat, 9 May 2009, Seth Daniel wrote:
>
>> I was hoping for a solution that didn't burn two signals.  I'm already
>> using the most obvious signals: HUP, USR1, USR2, KILL, QUIT, etc...
>> so I'm not exactly overflowing with extra signals. :o)
>
> I see ... in the next version of Log4perl (1.23), you'll be able to call
>
>     Log::Log4perl::Config->watcher->force_next_check();
>
> instead of using a signal:
>
>     http://github.com/mschilli/log4perl/commit/6c8609f1ba064d3f781769cb9e1b45638f3daa75
>
> (will probably go out soon).


That's fantastic.  Thank you Mike.

-- 
seth /\ sethdaniel.org