[logback-user] Multiple FileAppenders writing to single file no longer working in Logback 1.2.3

[Ceki Gülcü]

Hi John,

Multiple appenders cannot write to the same file unless prudent mode is 
enabled. In the 1.2.x series, logback prevents the same file to be 
opened by different FileAppenders as this is usually a configuration 
error. The 1.3 does not have this check.

I suggest that you use a single FileAppender but add a filter according 
to your needs.

Best regards,
--
Ceki


On 23/09/2019 17:39, John Morton wrote:
> Hello again Logback users,
> 
> I’m “bumping” this thread as I’m still having to use Logback 1.1.3 for 
> my application. I’d like a bug to be opened in Logback if anyone could 
> confirm whether what I am trying to do “should work”. I do not know if 
> the way I set it up in Logback 1.1.3 is “supported” or not.
> 
> Please let me know, thank you so much!
> 
> - John
> 
> *From: *John Morton <jtmorton at calpoly.edu>
> *Date: *Wednesday, December 19, 2018 at 7:14 PM
> *To: *"logback-user at qos.ch" <logback-user at qos.ch>
> *Subject: *Multiple FileAppenders writing to single file no longer 
> working in Logback 1.2.3
> 
> Hello there Logback users. An application I’m responsible uses logback 
> for its internal logging. It logs to various files at various levels. 
> I’ve extended it successfully to reformat certain log messages and save 
> them into a new log called “combined-audit.log”. This is all within a 
> single JVM, logging to a file on a local filesystem.
> 
> The reason for the three loggers/appenders is that I want to log from 
> three different packages, at different levels, filter each differently, 
> and encode each differently. This is all necessary because I cannot make 
> changes to the app itself, so I’m trying to use Logback to accomplish my 
> needs.
> 
> The below configuration works in Logback 1.1.3 and not in Logback 1.2.3.
> 
> In Logback 1.2.3, only messages from one of the three loggers are logged 
> to the single file. When I change the file name to three different 
> files, messages from each logger are in each file.
> 
> I read through release notes from 1.1.3 to 1.2.3 and nothing jumped out 
> at me as having the potential to change this behavior.
> 
> Is this a supported configuration in 1.2.3? Does anyone have any ideas 
> for how to accomplish the objective?
> 
> <!-- Appends app audit messages to combined audit log -->
> 
> <appender name="COMBINED_AUDIT" class="ch.qos.logback.core.FileAppender">
> 
>      <File>${logging.directory}/combined-audit.log</File>
> 
>      <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
> 
>          <charset>UTF-8</charset>
> 
>          
> <Pattern>%date{ISO8601}|%mdc{m.remote_addr}|%mdc{m.jsessionid}||%msg%n</Pattern>
> 
>      </encoder>
> 
> </appender>
> 
> <logger name="j.k.l" level="ALL" additivity="false">
> 
>      <appender-ref ref="COMBINED_AUDIT"/>
> 
> </logger>
> 
> <!-- Appends LDAP auth messages to combined audit log -->
> 
> <appender name="COMBINED_LDAP" class="ch.qos.logback.core.FileAppender">
> 
>      <File>${logging.directory}/combined-audit.log</File>
> 
>      <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
> 
>          <charset>UTF-8</charset>
> 
>          
> <Pattern>%date{ISO8601}|%mdc{m.remote_addr}|%mdc{m.jsessionid}|%replace(%replace(%replace(%msg){'^.*resultCode=',''}){',.*identifier=','|'}){', 
> context=.*$',''}|LDAP|||%n</Pattern>
> 
>      </encoder>
> 
>      <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
> 
>          <evaluator>
> 
>              <expression>return message.contains("authenticate 
> response=");</expression>
> 
>          </evaluator>
> 
>          <OnMatch>ACCEPT</OnMatch>
> 
>          <OnMismatch>DENY</OnMismatch>
> 
>      </filter>
> 
> </appender>
> 
> <logger name="a.b.c.d" level="DEBUG" additivity="false">
> 
>      <appender-ref ref="COMBINED_LDAP"/>
> 
> </logger>
> 
> <!-- Appends LDAP invalid username messages to combined audit log -->
> 
> <appender name="COMBINED_INVALID_USERNAME" 
> class="ch.qos.logback.core.FileAppender">
> 
>      <File>${logging.directory}/combined-audit.log</File>
> 
>      <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
> 
>          <charset>UTF-8</charset>
> 
>          
> <Pattern>%date{ISO8601}|%mdc{m.remote_addr}|%mdc{m.jsessionid}|INVALID_USERNAME||LDAP|||%n</Pattern>
> 
>      </encoder>
> 
>      <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
> 
>          <evaluator>
> 
>              <expression>return message.contains("failed using 
> filter=");</expression>
> 
>          </evaluator>
> 
>          <OnMatch>ACCEPT</OnMatch>
> 
>          <OnMismatch>DENY</OnMismatch>
> 
>      </filter>
> 
> </appender>
> 
> <logger name="v.w.x.y.z" level="INFO" additivity="false">
> 
>      <appender-ref ref="COMBINED_INVALID_USERNAME"/>
> 
> </logger>
> 
> 
>