Re: [log4perl-devel] open files when running init_and_watch

[Martin J. E. <mar...@ea...>]

Mike,

Thanks for the reply
see below:

Mike Schilli wrote:
> On Fri, 3 Mar 2006, Martin J. Evans wrote:
> 
> 
>>I was surprised to see every log file named in my log4.conf file
>>under "appender.XX.filename" had been created and was open.
> 
> 
> That's exactly how Log::Log4perl's file appender works. It opens all
> log files at init(), not when you obtain a logger.

why?

Perhaps this highlights my misunderstanding then.

I don't understand why it does this.

I thought calling get_logger would actually open the file
and init_and_watch would simply parse the conf file, check it
was OK and watch the conf file.

If I'd called get_logger(x::y::z) then I could understand
the log file associated with x::y::z and x::y being opened
but If I call get_logger(x::y) then why would the log
file associated with x::y::z be opened.

> I wonder how it is possible to run out of file descriptors with only
> three open files per process, though. Are you running hundreds of
> daemons simultaneously?

Perhaps I should have been clearer. I am running out of file descriptors
(but within a single process, not system wide) and it was that
which prompted me to look at what files I've got open. By the
time you add a file descriptor for the perl binary and every module
you've "use"ed, then every shared object you need it amounts to quite a 
bit (easily more than 64).

I did not expect log4perl to have created and opened the files I have 
not called get_logger for (or at least those below it). I wasn't
saying the 3 that log4perl open are the one and only cause of my
problem but they do include 2 I did not expect to be created
and opened.

> If opening the log files at startup imposes a problem, you could write
> your own log file appender that opens files at log() instead. If you
> look at the implementation of Log::Log4perl::Appender::File you'll see
> that it's actually quite simple.

I don't want files created and opened which I'm not going to log to.
In my mind if I've not called get_logger("x::y") then I'm
not going to log to the file that is defined by x::y (unless I've
called get_logger(x::y::z). I will look
at Appender but it seems to get ONLY the files opened which I'm
actually going to use in the current process I need a separate
conf file for each process which only defines the appenders
I intend using this time around. If that is the way it is
- fair enough - I can live with that.

As I said, perhaps I've misunderstood appenders and the conf file
but I'm "currently" at a loss to understand why a file is created
and opened when there is no likelihood of anything being written
to it. Perhaps you could put me right on any misunderstanding
I have.

Martin

>>This may
>>be my misunderstanding of the way log4perl works but it is
>>undesirable for me so I wondered if either a) these log files should
>>not be open or b) if my conf file was wrong. Given:
>>
>>log4perl.logger.Server = WARN
>>log4perl.logger.Server.Markets.Close = DEBUG, A1
>>log4perl.appender.A1=Log::Dispatch::File
>>log4perl.appender.A1.filename=/tmp/markets_close.log
>>log4perl.appender.A1.mode=append
>>log4perl.appender.A1.layout=Log::Log4perl::Layout::PatternLayout
>>log4perl.appender.A1.layout.ConversionPattern=%d %p> %F{1}:%L %M - %m%n
>>log4perl.appender.A1.Threshold=INFO
>>
>>log4perl.logger.Server.CGI.Post = DEBUG, A3
>>log4perl.appender.A3=Log::Dispatch::File
>>log4perl.appender.A3.filename=/tmp/cgi_post.log
>>log4perl.appender.A3.mode=append
>>log4perl.appender.A3.layout=Log::Log4perl::Layout::PatternLayout
>>log4perl.appender.A3.layout.ConversionPattern=%d %p> %F{1}:%L %M - %m%n
>>
>>log4perl.logger.Server.Queued = DEBUG, A5
>>log4perl.appender.A5=Log::Dispatch::File
>>log4perl.appender.A5.filename=/tmp/queued.log
>>log4perl.appender.A5.mode=append
>>log4perl.appender.A5.layout=Log::Log4perl::Layout::PatternLayout
>>log4perl.appender.A5.layout.ConversionPattern=%d %p> %F{1}:%L %M - %m%n
>>
>>why are A1.filename, A3.filename and A5.filename all created and open when I
>>run the above Perl. I would have expected A5.filename to be opened when I did
>>get_logger("Server::Queued") but no files other than log4.conf to be open when
>>all I've done is init_and_watch.
>>
>>Any ideas.
>>
>>Martin