Re: Defer evaluation of FileAppender filename until file is opened?

[Doug Wegscheid]

 Found it: need to make sure we have a key for the route, even if it won't be 
used. Added pattern="x" to 























Works perfectly!

On Wednesday, February 5, 2020, 2:48:30 AM EST, Doug Wegscheid 
 wrote:  
 
  That looks promising, but I am having an issue with the RoutingAppender 
throwing an NPE when the first event gets past the filter on the 
RoutingAppender:
2020-02-05 02:38:08,798 Log4j2-TF-1-AsyncLogger[AsyncContext@2cdf8d8a]-1 ERROR 
An exception occurred processing Appender MyRoute java.lang.NullPointerException
    at 
java.base/java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.getAppender(RoutingAppender.java:286)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.getControl(RoutingAppender.java:249)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.append(RoutingAppender.java:228)
    at 
org.apache.logging.log4j.core.config.AppenderControl.tryCallAppender(AppenderControl.java:156)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppender0(AppenderControl.java:129)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppenderPreventRecursion(AppenderControl.java:120)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:84)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:543)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.processLogEvent(LoggerConfig.java:502)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:485)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:473)
    at 
org.apache.logging.log4j.core.config.AwaitCompletionReliabilityStrategy.log(AwaitCompletionReliabilityStrategy.java:98)
    at 
org.apache.logging.log4j.core.async.AsyncLogger.actualAsyncLog(AsyncLogger.java:485)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEvent.execute(RingBufferLogEvent.java:161)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEventHandler.onEvent(RingBufferLogEventHandler.java:46)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEventHandler.onEvent(RingBufferLogEventHandler.java:29)
    at 
com.lmax.disruptor.BatchEventProcessor.processEvents(BatchEventProcessor.java:168)
    at com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:125)
    at java.base/java.lang.Thread.run(Thread.java:834)

I suspect I am missing something in my configuration?



    
        
            
        
        
            
            
                
                    
                        
                    
                
            
        
    
    
        
            
            
        
    



    On Wednesday, February 5, 2020, 12:14:13 AM EST, Ralph Goers 
 wrote:  
 
 Yes, so your best bet is to use the RoutingAppender and only supply a default 
Route. The Appender itself will only be created when something is logged to the 
Route.

Ralph

> On Feb 4, 2020, at 6:55 PM, Doug Wegscheid  wrote:
> 
> yes, that works as designed, but does not resolve my problem. The filename is 
> not evaluated when the first event is written (after we have a good 
> date/time), it's evaluated when log4j2 is configured (which is before when we 
> have a good date/time set).
>    On Tuesday, February 4, 2020, 08:19:16 PM EST, Ralph Goers 
> wrote:  
> 
> The FileAppender has an option named createOnDemand. If you set it to true 
> then the file will only be created when a log event is written to it. See 
> http://logging.apache.org/log4j/2.x/manual/appenders.html#FileAppender 
> .
> 
> Ralph
> 
> 
> 
>> On Feb 4, 2020, at 2:10 PM, Doug Wegscheid  wrote:
>> 
>> 
>> I am trying to have log4j2 write log files with names mmdd-HHMMSS.log, 
>> but not start writing the file until we have a good system time (>year 
>> 1986). I have an application running on a system that boots up, and takes a 
>> while to get the correct time; until that happens, the system thinks it's 
>> back in 1970, and there really is no point to writing a log file with a bum 
>> date.
>> 
>> Using a custom filter, I can get the FileAppender to not write any events 
>> until the system time is set. I can get the FileAppender to not open the 
>> file until the first event is passed by the custom filter 
>> (createOnDemand="true"). Using Log4J2 - assigning file appender filename at 
>> runtime, I can get the file named mmdd-HHMMSS.log, but the 
>> mmdd-HHMMSS.log in the configuration XML seems to get evaluated when 
>> log4j2 is initialized (not when the file is opened), 

Re: Defer evaluation of FileAppender filename until file is opened?

[Doug Wegscheid]

 That looks promising, but I am having an issue with the RoutingAppender 
throwing an NPE when the first event gets past the filter on the 
RoutingAppender:
2020-02-05 02:38:08,798 Log4j2-TF-1-AsyncLogger[AsyncContext@2cdf8d8a]-1 ERROR 
An exception occurred processing Appender MyRoute java.lang.NullPointerException
    at 
java.base/java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.getAppender(RoutingAppender.java:286)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.getControl(RoutingAppender.java:249)
    at 
org.apache.logging.log4j.core.appender.routing.RoutingAppender.append(RoutingAppender.java:228)
    at 
org.apache.logging.log4j.core.config.AppenderControl.tryCallAppender(AppenderControl.java:156)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppender0(AppenderControl.java:129)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppenderPreventRecursion(AppenderControl.java:120)
    at 
org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:84)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:543)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.processLogEvent(LoggerConfig.java:502)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:485)
    at 
org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:473)
    at 
org.apache.logging.log4j.core.config.AwaitCompletionReliabilityStrategy.log(AwaitCompletionReliabilityStrategy.java:98)
    at 
org.apache.logging.log4j.core.async.AsyncLogger.actualAsyncLog(AsyncLogger.java:485)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEvent.execute(RingBufferLogEvent.java:161)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEventHandler.onEvent(RingBufferLogEventHandler.java:46)
    at 
org.apache.logging.log4j.core.async.RingBufferLogEventHandler.onEvent(RingBufferLogEventHandler.java:29)
    at 
com.lmax.disruptor.BatchEventProcessor.processEvents(BatchEventProcessor.java:168)
    at com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:125)
    at java.base/java.lang.Thread.run(Thread.java:834)

I suspect I am missing something in my configuration?



























On Wednesday, February 5, 2020, 12:14:13 AM EST, Ralph Goers 
 wrote:  
 
 Yes, so your best bet is to use the RoutingAppender and only supply a default 
Route. The Appender itself will only be created when something is logged to the 
Route.

Ralph

> On Feb 4, 2020, at 6:55 PM, Doug Wegscheid  wrote:
> 
> yes, that works as designed, but does not resolve my problem. The filename is 
> not evaluated when the first event is written (after we have a good 
> date/time), it's evaluated when log4j2 is configured (which is before when we 
> have a good date/time set).
>    On Tuesday, February 4, 2020, 08:19:16 PM EST, Ralph Goers 
> wrote:  
> 
> The FileAppender has an option named createOnDemand. If you set it to true 
> then the file will only be created when a log event is written to it. See 
> http://logging.apache.org/log4j/2.x/manual/appenders.html#FileAppender 
> .
> 
> Ralph
> 
> 
> 
>> On Feb 4, 2020, at 2:10 PM, Doug Wegscheid  wrote:
>> 
>> 
>> I am trying to have log4j2 write log files with names mmdd-HHMMSS.log, 
>> but not start writing the file until we have a good system time (>year 
>> 1986). I have an application running on a system that boots up, and takes a 
>> while to get the correct time; until that happens, the system thinks it's 
>> back in 1970, and there really is no point to writing a log file with a bum 
>> date.
>> 
>> Using a custom filter, I can get the FileAppender to not write any events 
>> until the system time is set. I can get the FileAppender to not open the 
>> file until the first event is passed by the custom filter 
>> (createOnDemand="true"). Using Log4J2 - assigning file appender filename at 
>> runtime, I can get the file named mmdd-HHMMSS.log, but the 
>> mmdd-HHMMSS.log in the configuration XML seems to get evaluated when 
>> log4j2 is initialized (not when the file is opened), so my file name is 
>> still 19700101-00.log.
>> 
>> Is there a way to defer evaluation of the name for a log4j2 FileAppender 
>> until the file is actually opened? Alternatively, is there a sneaky way to 
>> use RollingFileAppender to do this? (I don't see a way to change the 
>> filename of the current file there, just old files)
>> 
>> I could do a custom appender (FileAppender/FileManager just are not all that 
>> long), but I'm trying to avoid that 

Re: Defer evaluation of FileAppender filename until file is opened?

[Ralph Goers]

Yes, so your best bet is to use the RoutingAppender and only supply a default 
Route. The Appender itself will only be created when something is logged to the 
Route.

Ralph

> On Feb 4, 2020, at 6:55 PM, Doug Wegscheid  wrote:
> 
> yes, that works as designed, but does not resolve my problem. The filename is 
> not evaluated when the first event is written (after we have a good 
> date/time), it's evaluated when log4j2 is configured (which is before when we 
> have a good date/time set).
>On Tuesday, February 4, 2020, 08:19:16 PM EST, Ralph Goers 
>  wrote:  
> 
> The FileAppender has an option named createOnDemand. If you set it to true 
> then the file will only be created when a log event is written to it. See 
> http://logging.apache.org/log4j/2.x/manual/appenders.html#FileAppender 
> .
> 
> Ralph
> 
> 
> 
>> On Feb 4, 2020, at 2:10 PM, Doug Wegscheid  wrote:
>> 
>> 
>> I am trying to have log4j2 write log files with names mmdd-HHMMSS.log, 
>> but not start writing the file until we have a good system time (>year 
>> 1986). I have an application running on a system that boots up, and takes a 
>> while to get the correct time; until that happens, the system thinks it's 
>> back in 1970, and there really is no point to writing a log file with a bum 
>> date.
>> 
>> Using a custom filter, I can get the FileAppender to not write any events 
>> until the system time is set. I can get the FileAppender to not open the 
>> file until the first event is passed by the custom filter 
>> (createOnDemand="true"). Using Log4J2 - assigning file appender filename at 
>> runtime, I can get the file named mmdd-HHMMSS.log, but the 
>> mmdd-HHMMSS.log in the configuration XML seems to get evaluated when 
>> log4j2 is initialized (not when the file is opened), so my file name is 
>> still 19700101-00.log.
>> 
>> Is there a way to defer evaluation of the name for a log4j2 FileAppender 
>> until the file is actually opened? Alternatively, is there a sneaky way to 
>> use RollingFileAppender to do this? (I don't see a way to change the 
>> filename of the current file there, just old files)
>> 
>> I could do a custom appender (FileAppender/FileManager just are not all that 
>> long), but I'm trying to avoid that if possible.
>> 



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Re: Defer evaluation of FileAppender filename until file is opened?

[Doug Wegscheid]

 yes, that works as designed, but does not resolve my problem. The filename is 
not evaluated when the first event is written (after we have a good date/time), 
it's evaluated when log4j2 is configured (which is before when we have a good 
date/time set).
On Tuesday, February 4, 2020, 08:19:16 PM EST, Ralph Goers 
 wrote:  
 
 The FileAppender has an option named createOnDemand. If you set it to true 
then the file will only be created when a log event is written to it. See 
http://logging.apache.org/log4j/2.x/manual/appenders.html#FileAppender 
.

Ralph

 

> On Feb 4, 2020, at 2:10 PM, Doug Wegscheid  wrote:
> 
> 
> I am trying to have log4j2 write log files with names mmdd-HHMMSS.log, 
> but not start writing the file until we have a good system time (>year 1986). 
> I have an application running on a system that boots up, and takes a while to 
> get the correct time; until that happens, the system thinks it's back in 
> 1970, and there really is no point to writing a log file with a bum date.
> 
> Using a custom filter, I can get the FileAppender to not write any events 
> until the system time is set. I can get the FileAppender to not open the file 
> until the first event is passed by the custom filter (createOnDemand="true"). 
> Using Log4J2 - assigning file appender filename at runtime, I can get the 
> file named mmdd-HHMMSS.log, but the mmdd-HHMMSS.log in the 
> configuration XML seems to get evaluated when log4j2 is initialized (not when 
> the file is opened), so my file name is still 19700101-00.log.
> 
> Is there a way to defer evaluation of the name for a log4j2 FileAppender 
> until the file is actually opened? Alternatively, is there a sneaky way to 
> use RollingFileAppender to do this? (I don't see a way to change the filename 
> of the current file there, just old files)
> 
> I could do a custom appender (FileAppender/FileManager just are not all that 
> long), but I'm trying to avoid that if possible.
>