Hello!

I'm quite new in using log4net. :-)
And perhaps you have a quick and easy solution for my problem.

I have an windows application which can be started more than once.
Inside the config file I can set the logfile and path.
But when I start my application more than once, I receive a "file in
use" exception.

Is it possible to set the logfile path at runtime?

Thank you for your help.

best regards,
Mad

> But when I start my application more than once, I receive a "file in
use" exception.  Is it possible to set the logfile path at runtime?

You can also try using a "minimal lock," which lets multiple processes
write to the same file.  Just add the following to your appender config:

<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />

This is covered in the log4net config examples in the FileAppender
section:

http://logging.apache.org/log4net/release/config-examples.html

--Chris

--
Chris Jerdonek
Software Developer
P: (415) 357-3618 Ext. 1357
Granicus, Inc.

is it possible to combine this with a RollingFileAppender?

best regards,
Mad

> is it possible to combine this with a RollingFileAppender?

Yes.  This is because "LockingModel" is a property of the FileAppender
class, and the RollingFileAppender class extends FileAppender.  You can
see this for yourself if you go to the log4net SDK reference and click
on log4net.Appender -> RollingFileAppender Class.  The SDK reference is
available here:

http://logging.apache.org/log4net/release/sdk/index.html

It's also available by clicking on "SDK Reference" in the left column of
the main log4net web site.

--Chris


--
Chris Jerdonek
Software Developer
P: (415) 357-3618 Ext. 1357
Granicus, Inc.

Hello!

Thanks for reply!

Yes, it works. But when I log many entries in both processes I receive a
log4net:ERROR [RollingFileAppender] Unable to acquire lock on file
and after that an INTERNAL ERROR. Append is False but OutputFile ...
already exists.

There is no way to set the logfile path manual?
Or can I specify the folder to user data folder?

best regards,
Mad

I wouldn't recommend using the RollingFileAppender with the MinimalLock. There's no way for one instance of the program to know that another instance has rolled the file. The MinimalLock is slow compared to an ExclusiveLock. The most effecient file based appender across multiple processes would probably be a normal FileAppender with a mutext based lock so the processes can coordinate who is writing to the file. Someone has already implemented such a class:

 http://www.mail-archive.com/log4net-user@logging.apache.org/msg04116.html

That would be a good locking model to support in the next release.

Hello!

Thanks for the code example.
Can you please give me a hint where I should put this peace of code
inside the log4net solution?

thank you.

Hello!

I made it.
Simple add the code to inside #region Locking Models
and activate the new locking with
<lockingModel type="log4net.Appender.FileAppender+MutexLock" />

Works great! :-)

Thank you very much!

You can also place it in another assembly:

 <lockingModel type="Company.Logging.MutexLock, Company.Logging" />