You can register a pattern in the config file itself:
<file type="log4net.Util.PatternString">
<converter>
<name value="instanceId" />
<type value="MyStuff.InstanceIdPatternConverter, MyStuff" />
</converter>
<conversionPattern value="..\Logs\Instance%instanceId\log.xml" />
</file>
This may not be the most elegant way of registering new patterns, but it
works and it does not have any ordering issues with respect to
registering before the config is loaded, also there is no possibility
for there to be a pattern collision between 2 different global patterns.
FYI the FileAppender does now support a locking model which allows
multiple processes to write to the same file, e.g.:
<appender name="FileAppender" type="log4net.Appender.FileAppender">
<file value="${TMP}\log-file.txt" />
<appendToFile value="true" />
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%ndc] -
%message%newline" />
</layout>
</appender>
Nicko
> -----Original Message-----
> From: p.reuse [mailto:[EMAIL PROTECTED]
> Sent: 14 April 2005 16:41
> To: Log4NET User
> Subject: Re: RollingFileAppender Problems using Multiple App Instances
>
> Hi,
>
> The %processid approach seems like a nice way at first, but
> this would cause an explosion of logfiles.
>
> My solution is to append an extra Patternconverter that uses
> a mutex to find an available application 'instance' number.
> Together with the config-file I get a seperate logging
> directory for each instance that is running simultaneous.
>
> <appender name="BasicFileAppender"
> type="log4net.Appender.FileAppender">
> <file type="Net.ExtendedPatternString"
> value="..\Logs\Instance%instanceId\log.xml" /> ...
> The result is that I have as many logdirectories as the
> number of application instances that were open at the same time.
>
> There is only one little problem :
> I need to add a PatternConverter to the PatternString object
> [AddConverter("instanceId",
> typeof(InstanceIdPatternConverter));] , but I need to do this
> before the config file is processed, and not on an instance
> of the class
>
> At this time I do it with 3 classes : ExtendedPatternString,
> ExtendedPatternStringConverter, InstanceIdPatternConverter,
> and registering the ExtendedPatternString.
>
> Wouldn't it be a lot nicer if a static method existed on the
> PatternString class were converters could be added at
> application startup, of course before processing the log4net
> config-file:
> class PatternString
> {
> static void AddGlobalRulesRegistry(string name, Type
> patternConverterType)
> {
> s_globalRulesRegistry.Add(name, patternConverterType);
> }
> }
>
> This way we only need a simple PatternConverter class,
> register the class on startup, and done with it.
> And now we can have all kinds of exotic patterns :).
>
> grtz,
> Paul
>
>
> Nicko Cadell wrote:
>
> The FileAppender (and RollingFileAppender) takes an
> exclusive lock on
> the output file. This prevents multiple applications
> writing to the same
> log file. As you have 2 instances of the same
> application that are
> presumably using the same log4net config file then it is rather
> challenging to write to different files. There are a
> couple of ways
> around this, firstly you can subclass the FileAppender
> and override the
> File property to unique the file name (e.g. add the process id).
> Alternatively you could try using the latest version of
> log4net from CVS
> which supports using a patterned string to add the
> process id to the
> file name as follows:
>
> <file type="log4net.Util.PatternString"
> value="log-[%processid].txt" />
>
> Nicko
>
>
>
> -----Original Message-----
> From: Nick Jagger [mailto:[EMAIL PROTECTED]
> Sent: 03 March 2005 10:53
> To: [email protected]
> Subject: RollingFileAppender Problems using
> Multiple App Instances
>
> Hi,
>
> I'm having problems trying to log to a log file using
> multiple instances of an .exe. I've seen this
> problem on the
> forum a few times but unfortunately can't seem
> to find any
> satisfactory answers.
>
> Some solutions point to using a RemotingAppender but
> unfortunately a) I'm having trouble finding
> documentation on
> how exactly to use this, and b) I suspect this approach
> requires a completely separate program running
> to handle the
> remote logging calls, something I'm loathe to
> having to run -
> why should I need a separate dedicated
> application just to
> write to a log file??
>
> Additionally, I've tried setting up 2 different
> log files,
> one for each instance of my app., but again
> once the first
> instance calls Configure() (using app.config)
> it creates and
> locks both files! Argghhhhh...!! Sorry, but I'm really
> starting to pull my hair out over this one, any
> help at all
> would be really appreciated.
>
> Thanks,
> Nick
>
>
>
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