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Tomcat Access logs

Access logs are customized logs, which record all requests processed by the server giving information about:

  • The user that has accessed the application
  • What components of the application are accessed
  • Remote IP and so on

These logs play a vital role in traffic analysis of many applications to analyze the bandwidth requirement and they also help in troubleshooting the application under a heavy load. These logs are configured in  server.xml in  TOMCAT_HOME/conf .
You can configure access logs according to the environment and your auditing requirements. Let's see the pattern format of the access logs and understand how we can customize the logging format:


And now some explanation about the parameters contained in the AccessLogValve:

  • Class Name: This parameter defines the class name used for the generation of logs. By default, Apache Tomcat 7 uses the  org.apache.catalina.valves.AccessLogValve class for the access logs.
  • Directory: This parameter defines the directory location for the log file. All the log files are generated in the log directory— TOMCAT_HOME/logs —but we can customize the log location based on our environment setup and then update the directory path in the definition of the access logs.
  • Prefix: This parameter defines the prefix of the access log filename, that is, by default, the access log files are generated by the name  localhost_access_log.yy-mm-dd.txt .
  • Suffix: This parameter defines the file extension of the log file. Currently it is in  .txt format.
  • Pattern: This parameter defines the format of the log file. The pattern is a combination of values defined by the administrator, for example,  %h = remote host address. 

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