[logback-dev] programmatic configuration

[Cheenu]

Cool - that is exactly what I was looking for.

Thanks much
Cheenu

On Feb 28, 2009, at 6:05 AM, Ceki Gulcu wrote:

>
> Heelo Cheenu,
>
> You can configure logback programmatically which is exactly what  
> Joran (logback's configuration framework) does when it reads  
> configuration files.
>
> The log4j example you provide would problay need to be modified as  
> follows:
>
> import org.slf4j.LoggerFactory;
>
> import ch.qos.logback.classic.Logger;
> import ch.qos.logback.classic.LoggerContext;
> import ch.qos.logback.classic.PatternLayout;
> import ch.qos.logback.classic.spi.LoggingEvent;
> import ch.qos.logback.core.FileAppender;
>
> public class Main {
>
>  public static void main(String[] args) {
>     Logger logger = (Logger) LoggerFactory.getLogger("abc.xyz");
>
>    LoggerContext lc = (LoggerContext)  
> LoggerFactory.getILoggerFactory();
>    FileAppender<LoggingEvent> fileAppender =
>                      (FileAppender<LoggingEvent>)  
> logger.getAppender("file");
>    if(fileAppender != null) {
>      fileAppender.stop();
>      fileAppender.setFile("new.log");
>      PatternLayout pl = new PatternLayout();
>      pl.setPattern("%d %5p %t [%c:%L] %m%n)");
>      pl.setContext(lc);
>      pl.start();
>      fileAppender.setLayout(pl);
>      fileAppender.setContext(lc);
>      fileAppender.start();
>    }
>    ... etc	
>  }
> }
>
> Logback offers a much more convenient alternative in the form of  
> variable substitution. See also [1,2,3] below.
>
> You could set the name of the logging file as a java system property  
> at application launch, in which case you would not need to do any  
> programmatic configuration. You could also set a property  
> programmatically as shown in [2].
>
>
> [1] http://logback.qos.ch/manual/configuration.html#variableSubstitution
> [2] http://logback.qos.ch/faq.html#sharedConfiguration
> [3] http://logback.qos.ch/faq.html#overrideFromCL
>
> HTH,
>
> Cheenu wrote:
>> Is there a way to programmatically configure logback without using  
>> any config file at all.
>> I saw http://logback.qos.ch/xref/chapter3/MyApp3.html
>> and that is still configuring using a config file.
>> Use-case: multiple invocations of same app (with same classpath)  
>> needs to
>> log to different file appenders, possibly with different patterns.
>> Hence, need facility to dynamically configure these at runtime (at  
>> startup).
>> In log4j, I can do this using
>> Logger logger = Logger.getLogger("abc.xyz");
>> FileAppender fileAppender = (FileAppender)logger.getAppender("file");
>> if(fileAppender != null) {
>>  fileAppender.setFile("new.log");
>>  fileAppender.setLayout(new PatternLayout("%d{ISO8601} %5p %t [%c: 
>> %L] %m%n"));
>>  fileAppender.activateOptions();
>> }
>> How do I do similar thing in logback?
>> Thanks
>> Cheenu
> -- 
> Ceki Gülcü
> Logback: The reliable, generic, fast and flexible logging framework  
> for Java.
> http://logback.qos.ch
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