how to log error in one file and info in other file with backlog

Question

How can I separate the logs into two files accordingly to the level? I found someone doing something very close but with console in one level and file in another (logging to different places throw filters). Additionally, I found a very interested question (logging to different places by setup two separate loggers) but, as far as I could understand it, the answer is to create two Logger instances what seems unnecessary if I can filter by level. Kindly, see below three things I have done so far:

it is working but all info goes to same file,
I try to separate according to levels by trying to create two roots tags but it just create two empty files
in order to narrow a bit more my question, I try to at least duplicate same info to two different files but it just create two empty files as well

First

       <property name="DEV_HOME" value="c:/temp" />
       <appender name="FILE-AUDIT"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
              <file>${DEV_HOME}/debug.log</file>
              <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                     <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
              </encoder>
              <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                     <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log
                        </fileNamePattern>
                     <timeBasedFileNamingAndTriggeringPolicy
class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                           <maxFileSize>10MB</maxFileSize>
                     </timeBasedFileNamingAndTriggeringPolicy>
              </rollingPolicy>
       </appender>
       <root level="info">
              <appender-ref ref="FILE-AUDIT" />
       </root>

Second

           <property name="DEV_HOME" value="c:/temp" />
           <appender name="FILE1"
                  class="ch.qos.logback.core.rolling.RollingFileAppender">
                  <file>${DEV_HOME}/debug1.log</file>
                  <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                         <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
                  </encoder>
                  <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                         <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log
                            </fileNamePattern>
                         <timeBasedFileNamingAndTriggeringPolicy
    class="ch.qos.lo       <property name="DEV_HOME" value="c:/temp" />
       <appender name="FILE-AUDIT"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
              <file>${DEV_HOME}/debug.log</file>
              <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                     <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
              </encoder>
              <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                     <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log
                        </fileNamePattern>
                     <timeBasedFileNamingAndTriggeringPolicy
class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                           <maxFileSize>10MB</maxFileSize>
                     </timeBasedFileNamingAndTriggeringPolicy>
              </rollingPolicy>
       </appender>
       <root level="info">
              <appender-ref ref="FILE-AUDIT" />
       </root>gback.core.rolling.SizeAndTimeBasedFNATP">
                               <maxFileSize>10MB</maxFileSize>
                         </timeBasedFileNamingAndTriggeringPolicy>
                  </rollingPolicy>
           </appender>
           <root level="info">
                  <appender-ref ref="FILE1" />
           </root>

           <appender name="FILE2"
                  class="ch.qos.logback.core.rolling.RollingFileAppender">
                  <file>${DEV_HOME}/debug2.log</file>
                  <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                         <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
                  </encoder>
                  <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                         <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log
                            </fileNamePattern>
                         <timeBasedFileNamingAndTriggeringPolicy
    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                               <maxFileSize>10MB</maxFileSize>
                         </timeBasedFileNamingAndTriggeringPolicy>
                  </rollingPolicy>
           </appender>
           <root level="warn">
                  <appender-ref ref="FILE2" />
           </root>
    </configuration>

Third

<appender name="FILE1" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${DEV_HOME}/debug1.log</file>
    <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
        <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
        <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
        <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
        <maxFileSize>10MB</maxFileSize>
        </timeBasedFileNamingAndTriggeringPolicy>
    </rollingPolicy>
</appender>
<appender name="FILE2" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${DEV_HOME}/debug2.log</file>
    <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
        <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
    <fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log
    </fileNamePattern>
    <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
    <maxFileSize>10MB</maxFileSize>
    </timeBasedFileNamingAndTriggeringPolicy>
</rollingPolicy>
</appender>
<root level="info">
    <appender-ref ref="FILE1" />
    <appender-ref ref="FILE2" />
</root>

I found a couple of answers in http://stackoverflow.com/questions/2488558/logback-to-log-different-messages-to-two-files but that is for logcback, im not sure if is what you are looking for. — cesaregb, Jul 04 '16 at 14:55

score 2 · Accepted Answer · answered Aug 02 '19 at 10:09

I think what you are looking for is filter element within a new appender which writes only the levels above a given log-level to a new file. Then you can address these two appenders in the same logger.

Here is an example:

<configuration>
    <appender name="RollingFile" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>log/app.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>log/app.%d{yyyy-MM-dd}.log</fileNamePattern>
            <maxHistory>14</maxHistory>
        </rollingPolicy>

        <encoder>
            <pattern>%d{HH:mm:ss.SSS} %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="ErrorRollingFile" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>log/app-warn.log</file>
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>ERROR</level>
        </filter>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>log/app.%d{yyyy-MM-dd}-warn.log</fileNamePattern>
            <maxHistory>14</maxHistory>
        </rollingPolicy>

        <encoder>
            <pattern>%d{HH:mm:ss.SSS} %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yy/MM/dd HH:mm:ss.SSS} %-5level %-38logger{38} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="WARN">
        <appender-ref ref="STDOUT"/>
    </root>

    <logger name="com.my.package" level="INFO">
        <appender-ref ref="RollingFile"/>
        <appender-ref ref="ErrorRollingFile"/>
    </logger>
</configuration>

how to log error in one file and info in other file with backlog

1 Answers1