Interface ComponentLog

All Known Implementing Classes:
NopComponentLog

public interface ComponentLog

The ComponentLog provides a mechanism to ensure that all NiFi components are logging and reporting information in a consistent way. When messages are logged to the ComponentLog, each message has the following characteristics:

  • The toString() of the component is automatically prepended to the message so that it is clear which component is providing the information. This is important, since a single component may have many different instances within the same NiFi instance.
  • If the last value in an Object... argument that is passed to the logger is a Throwable, then the logged message will include a toString() of the Throwable; in addition, if the component's logger is set to DEBUG level via the logback configuration, the Stacktrace will also be logged. This provides a mechanism to easily enable stacktraces in the logs when they are desired without filling the logs with unneeded stack traces for messages that end up occurring often.
  • Any message that is logged with a Severity level that meets or exceeds the configured Bulletin Level for that component will also cause a Bulletin to be generated, so that the message is visible in the UI, allowing Dataflow Managers to understand that a problem exists and what the issue is.