Logging

Basics

• The library performs structured event logging using the SLF4J API
• All events are logged via loggers with top-level package name 'automorph'
• The log message itself specifies the logged event type only
• Event properties are passed into the associated Mapped Diagnostic Context
• It is thus highly recommended to configure the utilized SL4J implementation to include MDC in the logger output

Log level semantics

• ERROR - Non-recoverable errors
• WARN - Recoverable errors
• INFO - Main events (e.g. remote API call performed successfully, component initialized)
• DEBUG - Diagnostic events (e.g. request received, response sent)
• TRACE - Detailed diagnostic events (e.g. message body, message metadata)

Example configuration

An example logging configuration for Logback which supports setting the log level using the LOG_LEVEL environment variable:

<configuration>
  <!-- Disable Logback internal logging at startup -->
  <statusListener class="ch.qos.logback.core.status.NopStatusListener" />

  <!-- Release logging resources on application termination -->
  <shutdownHook class="ch.qos.logback.core.hook.DelayingShutdownHook"/>

  <!-- Simple console logging -->
  <appender name="Console" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%cyan(%date{HH:mm:ss.SSS}) [%highlight(%-5level)] %message - %gray(%mdc) %</pattern>
    </encoder>
  </appender>
    
  <!-- Root log level -->
  <root level="${LOG_LEVEL:-OFF}">
      <appender-ref ref="Console" />
  </root>

  <!-- Package-specific log level -->
  <logger name="automorph" level="${LOG_LEVEL:-INFO}"/>
</configuration>