As an admin I would like the ability to configure where audit logging is sent even after legacy audit logging is deprecated in Bitbucket version 8

Problem Description

• In Bitbucket 7.0 the audit logging changed
• When that changed occurred the following conditional was added to the logback-spring.xml:

  <springProperty scope="context" name="enableLegacyAuditLog"
                              source="audit.legacy.log" defaultValue="false"/>
              <if condition='property("enableLegacyAuditLog").equals("true")'>
                  <then>
                      <appender name="bitbucket.auditlog" class="ch.qos.logback.core.rolling.RollingFileAppender">
                          <encoder>
                              <charset>UTF-8</charset>
                              <pattern>%m%n</pattern>
                          </encoder>
                          <file>${log.dir}/audit/atlassian-bitbucket-audit.log</file>
                          <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
                              <fileNamePattern>${log.dir}/audit/atlassian-bitbucket-audit-%d.%i.log.gz</fileNamePattern>
                              <maxFileSize>25MB</maxFileSize>
                              <maxHistory>100</maxHistory>
                          </rollingPolicy>
                      </appender>
                      <!-- Enable audit logging and direct it to its own separate appender if it is enabled -->
                      <logger name="bitbucket.audit-log" level="DEBUG" additivity="true">
                          <appender-ref ref="bitbucket.auditlog"/>
                     </logger>
                  </then>
              </if>
  

• This conditional checks to see if legacy audit logging is enabled and if so it will revert to writing to the logfile specified in the appender definition
• I was able to get audit logging written to SYSLOG by adding changes inside the conditional and using the facility attribute USER eg.:

  <springProperty scope="context" name="enableLegacyAuditLog"
                              source="audit.legacy.log" defaultValue="false"/>
              <if condition='property("enableLegacyAuditLog").equals("true")'>
                  <then>
                      <appender name="bitbucket.auditlog" class="ch.qos.logback.core.rolling.RollingFileAppender">
                          <encoder>
                              <charset>UTF-8</charset>
                              <pattern>%m%n</pattern>
                          </encoder>
                          <file>${log.dir}/audit/atlassian-bitbucket-audit.log</file>
                          <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
                              <fileNamePattern>${log.dir}/audit/atlassian-bitbucket-audit-%d.%i.log.gz</fileNamePattern>
                              <maxFileSize>25MB</maxFileSize>
                              <maxHistory>100</maxHistory>
                          </rollingPolicy>
                      </appender>
                      <appender name="SYSLOG" class="ch.qos.logback.classic.net.SyslogAppender">
                              <syslogHost>172.28.128.103</syslogHost>
                          <facility>USER</facility>
                          <port>514</port>
                          <suffixPattern>[%thread] %logger %msg</suffixPattern>
                      </appender>
  
                      <!-- Enable audit logging and direct it to its own separate appender if it is enabled -->
                      <logger name="bitbucket.audit-log" level="DEBUG" additivity="true">
                          <appender-ref ref="bitbucket.auditlog"/>
                          <appender-ref ref="SYSLOG"/>
                     </logger>
                  </then>
              </if>
  

• From there legacy audit logging needed to be enabled by adding the following to the $BITBUCKET_HOME/shared/bitbucket.properties file:

  audit.legacy.log=true
  

• From here I can see the audit logging written to SYSLOG during startup:

  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186185 | com.atlassian.prettyurls.atlassian-pretty-urls-plugin | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186192 | com.atlassian.soy.soy-template-plugin | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186200 | com.atlassian.stash.plugins.stash-remote-event-bitbucket-server-spi | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186244 | com.atlassian.troubleshooting.plugin-bitbucket | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186251 | com.atlassian.webhooks.atlassian-webhooks-plugin | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186252 | com.springsource.net.jcip.annotations-1.0.0 | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186259 | tac.bitbucket.languages.de_DE | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186269 | tac.bitbucket.languages.fr_FR | - | - | -
  Apr 29 13:33:44 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log - | Plugin enabled | System | 1619703186286 | tac.bitbucket.languages.ja_JP | - | - | -
  Apr 29 13:35:16 vagrant systemd-networkd[1591]: eth1: DHCP: No routes received from DHCP server: No data available
  

• As well as when I perform an operation in the BASE audit scope like creating or deleting a user:

  Apr 29 13:42:28 vagrant [audit-broker-consumer-thread-707705260] bitbucket.audit-log 172.28.128.1 | User deleted | nhansberry | 1619703748024 | test | - | - | -
  

If this all relies on enabling legacy audit logging, this configuration will not work when legacy audit logging is deprecated in Bitbucket version 8 (see: https://confluence.atlassian.com/bitbucketserver/configuration-properties-776640155.html#Configurationproperties-Audit for deprecation notice)

Proposed Solution

• Implement a way to keep this functionality even after legacy audit logging is deprecated