Based on the official tomcat image, but with logs using logback.
Some environment variables are available to tune the logs:
- DEFAULT_LOG_LEVEL: Set the default log level.
- TOMCAT_LOG_LEVEL: Set the tomcat log level.
- TOMCAT_LOG_TYPE:
classic(default): The logs are humane readable. Access logs are going to stdout and the other logs are going to stderr.json: The logs will be formatted in a JSON suitable for logstash. Access logs are going to stdout and the other logs are going to stderr.logstash: The logs will be formatted in a JSON suitable for logstash (@cee) and sent by syslog/UDP. The access logs are going to stdout in json format. More variables are available for this mode:- TOMCAT_LOG_HOST: the target host
- TOMCAT_LOG_PORT: the target port
If you want to change the way things are logged, change the ${CATALINA_HOME}/conf/logback-custom.xml file.
If your application uses logback/log4j, it is recommended to not ship those libraries with your webapp. Just use the ones provided at tomcat level.
Other changes compared the official tomcat image:
- All the default webapps are removed.
- TLD and JAR scanners are disabled (faster startup).
- Resources caching is properly configured.