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Monitoring API-Level Logs

The advantage of having per-API log files is that it is very easy to analyze/monitor what went wrong in a particular REST API defined in WSO2 Micro Integrator by looking at the log files. The API log is an additional log file, which will contain a copy of the logs to a particular REST API.

Below are the configuration details to configure the logs of a REST API called TestAPI using log4j properties.

Open MI_HOME/conf/ file using your favorite text editor to configure log4j to log the API specific logs to a file. You can configure the logger for either INFO level logs or DEBUG level logs as follows:

Enabling log4j for an API

Follow the instructions below to enable log4j2 logs for a sample REST API (named TestAPI).

  1. Open up the file (stored in the MI_HOME/conf ) directory. 
  2. Let's define a new appender for the TestAPI API by adding the following section to the end of the file (starting in a new line).


    This configuration creates a log file named TestAPI.log in the folder MI_HOME/repository/logs folder.

    # API_APPENDER is set to be a DailyRollingFileAppender using a PatternLayout.
    appender.API_APPENDER.type = RollingFile = API_APPENDER
    appender.API_APPENDER.fileName = ${sys:carbon.home}/repository/logs/TestAPI.log
    appender.API_APPENDER.filePattern = ${sys:carbon.home}/repository/logs/wso2-ei-api-%d{MM-dd-yyyy}.log
    appender.API_APPENDER.layout.type = PatternLayout
    appender.API_APPENDER.layout.pattern = TID: [%d] %5p {%c} [%logger] - %m%ex%n
    appender.API_APPENDER.policies.type = Policies
    appender.API_APPENDER.policies.time.type = TimeBasedTriggeringPolicy
    appender.API_APPENDER.policies.time.interval = 1
    appender.API_APPENDER.policies.time.modulate = true
    appender.API_APPENDER.policies.size.type = SizeBasedTriggeringPolicy
    appender.API_APPENDER.strategy.type = DefaultRolloverStrategy
    appender.API_APPENDER.strategy.max = 20
    appender.API_APPENDER.filter.threshold.type = ThresholdFilter
    appender.API_APPENDER.filter.threshold.level = INFO
  3. Register the appender (named API_APPENDER):

  4. Define a new logger to filter out TestAPI related logs:
    logger.API_LOG.appenderRef.API_APPENDER.ref = API_APPENDER
  5. Register the API_LOG logger:

  6. Save the file.

Configuring the REST API

The log4j2 configurations in the file does not create logs for the REST API by default. Add a Log mediator to the REST API's in-sequence and configure it to log messages at INFO log level.

Dynamically changing log level

See the instructions on updating the log level.