Using a Python processor
Python processors in MiNiFi C++ are loaded from external files, and they keep running a function, while retaining the interpreter state. This makes them well-suited for tasks that require maintaining state between runs or executing initialization logic to be run only once. Learn how to integrate custom code seamlessly into a MiNiFi C++ agent by utilizing custom Python processors. You can unlock the full potential of your MiNiFi C++ agent by enhancing its functionality with the flexibility offered by Python processors.
The workflow of a Python processor:
- At startup, the MiNiFi C++ agent reads the Python script directory specified
in the
minifi.propertiesfile as the value of thenifi.python.processor.dirproperty. By default, this directory is set to MINIFI_HOME/minifi-python. - The agent scans the directory for compatible scripts and automatically registers them for use.
- Python files are evaluated during startup. Their
onSchedulefunction is invoked before starting a flow and theironTriggerfunction is called regularly as the processor is scheduled.
For more details, see the following example:
#!/usr/bin/env python
def describe(processor):
processor.setDescription("Adds an attribute to your flow files")
def onInitialize(processor):
processor.setSupportsDynamicProperties()
def onTrigger(context, session):
flow_file = session.get()
if flow_file is not None:
flow_file.addAttribute("Python attribute", "attributevalue")
session.transfer(flow_file, REL_SUCCESS)To add or update processors, place the Python files in the designated script directory and restart the agent.
