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Logging is one of the most important aspects of a production-grade server. A properly configured logging system is vital for identifying errors, security threats and usage patterns.
See the following topics for details:
Log types in WSO2 products
Listed below are the various log types that can be used with WSO2 products.
Separate log files are created for each of the log types given below in the
log4j.propertiesfile (stored in the
<PRODUCT_HOME>/repository/confdirectory). Carbon logs: All WSO2 products are shipped with log4j logging capabilities that generate administrative activities and server side logs (Carbon logs). Carbon logs are configured for a product in t
Java logging and Log4j integration: In addition to the logs from libraries that use Log4j, all logs from libraries (such as, Tomcat, Hazelcast and more) that use Java logging framework are also visible in the same log files. That is, when Java logging is enabled in Carbon, only the Log4j appenders will write to the log files. If the Java Logging Handlers have logs, these logs will be delegated to the log events of the corresponding Log4j appenders. A Pub/Sub registry pattern implementation has been used in the latter mentioned scenario to plug the handlers and appenders. The following default log4j appenders in the
log4j.propertiesfile are used for this implementation:
- Audit logs: Audit logs are used for tracking the sequence of actions that affect a particular task carried out in the server. These are also configured in the
log4j.propertiesfile (stored in the
- HTTP access logs: HTTP requests/responses are logged in access log(s) to monitor your application's usage, such as the persons who access it, how many hits it receives, the errors etc. These logs are configured in the
catalina-server.xmlfile (stored in the <
- Trace logs: These are used for tracing the behavior of services. Trace logs are configured in the
log4j.propertiesfile (stored in the
- Patch logs: This log contains details related to patches applied to the product. This log cannot be customized. See WSO2 Patch Application Process for more information.
- Product-specific logs: Each WSO2 product may generate other log files in addition to the Carbon logs, Audit logs, HTTP access logs and Patch logs. See the product's documentation for descriptions of these log files and instructions on how to configure and use them.
Configuring products for log monitoring
See the following information on configuring Carbon logs, Audit logs , HTTP access logs, and Trace logs for your WSO2 product.
- Configuring Carbon logs
You can easily configure Carbon logs using the management console of your product, or you can manually edit the
log4j.propertiesfile. It is recommended to use the management console to configure logging because all changes made to log4j through the management console persists in the WSO2 Registry. Therefore, those changes will be available after the server restarts and will get priority over what is defined in the log4j.properties file. Also, note that the logging configuration you define using the management console will apply at run time. However, if you modify the
log4j.propertiesfile and restart the server, the earlier log4j configuration that persisted in the registry will be overwritten. There is also an option in the management console to restore the original log4j configuration from the
Identifying forged messages: From Carbon 4.4.3 onwards, it is possible to use a UUID in log messages so that any forged messages can be easily identified. The UUID is logged using a new conversion character ‘K’ in the log pattern layout. By default, the UUID will be generated every time the server starts. However, you can configure your server to generate the UUID more or less frequently, by specifying an exact time interval in the
See the following topics for instructions:
Configuring Audit logs
Audit logs are enabled in WSO2 products by default. You can change the following default configuration by manually updating the the
Configuring HTTP access logs
See HTTP Access Logging for instructions on how to configure and use HTTP access logs.
- Configuring Trace logs
Trace logs are disabled by default in WSO2 products. To enable Trace logs, the preferred log4j appender should be configured with
TRACElevel as the threshold in the
log4j.propertiesfile. For example, if
CARBON_LOGFILEis the log4j appender, the threshold level should be changed to
TRACEas shown below. The default threshold is set to
Managing log growth
See the following content on managing the growth of Carbon logs and Audit logs:
Managing the growth of Carbon logs
Log growth (in Carbon logs) can be managed by the following configurations in the
- Configurable log rotation: By default, log rotation is on a daily basis.
- Log rotation based on time as opposed to size: This helps to inspect the events that occurred during a specific time.
- Log files are archived to maximise the use of space.
log4j-based logging mechanism uses appenders to append all the log messages into a file. That is, at the end of the log rotation period, a new file will be created with the appended logs and archived. The name of the archived log file will always contain the date on which the file is archived.
Limiting the size of Carbon log files
You can limit the size of the
<PRODUCT_HOME>/repository/logs/wso2carbon.log file by following the steps given below. This is useful if you want to archive the logs and get backups periodically.
log4j.appender.CARBON_LOGFILE=org.wso2.carbon.utils.logging.appenders.CarbonDailyRollingFileAppenderappender in the
log4j.propertiesfile as follows:
Add the following two properties under
If the size of the log file is exceeding the value defined in the
MaxFileSizeproperty, the content is copied to a backup file and the logs are continued to be added to a new empty log file. The
MaxBackupIndexproperty makes the Log4j maintain a maximum number of backup files for the logs.
Limiting the size of audit log files
In WSO2 servers, audit logs are enabled by default. We can limit the audit log files with the following configuration:
- Change the
log4j.appender.AUDIT_LOGFILE=org.wso2.carbon.logging.appenders.CarbonDailyRollingFileAppenderappender in the
<PRODUCT_HOME>/repository/conf/log4j.propertiesfile as follows:
- Add the following two properties under
In each WSO2 product, users can configure and adjust the logging levels for each type of activity/transaction. There are several ways to view and monitor the logs:
- Carbon logs (system logs and application logs) of a running Carbon instance can be monitoring using the management console.
- Carbon logs, as well as HTTP access logs will be printed on the command terminal that open when you execute the product startup script.
- Alternatively, all log files can be viewed from the
<PRODUCT_HOME>/repository/logsfolder. This folder contains Audit logs, HTTP access logs as well as the Carbon logs in separate log files with date stamps. Note that older Carbon logs are archived in the