About Logger

Class nifiapi.logging.Logger

Every instance of a Processor will be automatically provisioned with a logger, accessible throughself.logger. Importantly, the logger instance supplied is not an instance of Python logger, but a Proxy to the Java logger object, and therefore available methods differ.

caution

Note that nifi.logging.Logger class does not have warning method; Use logger.warn instead.

Here is a breakdown of how the two relate to each other:

Standard Python Logger	NiFi API Logger
noset
	trace
debug	debug
info	info
warning	warn
error	error
critical

e.g.:

from nifiapi.flowfiletransform import (
    FlowFileTransform,
    FlowFileTransformResult,
)

class Processor(FlowFileTransform):
    (...)

    def transform(
        self, context: ProcessContext, flow_file
    ) -> FlowFileTransformResult:
        '''
        Parameters:
            context (ProcessContext)
            flow_file

        Returns:
            FlowFileTransformResult
        '''
        self.logger.warn("Called transform method.")
        
        return FlowFileTransformResult("success")