Our NiFi is 0.7.x. I understand that it is possible to set
customer-specific configuration parameters in a second config file similar
to nifi.properties. I have this requirement:
R1- allow engineering leads to set valid message types in a simple python
list, like so: validTypes = ['larry','curly','moe']
R2- application specific parms such as the validTypes list should be easily
editable by lead engineers who have no knowledge of NiFi, and so should be
maintained in a simple system file (text or xml, for example)
R3- after editing this file, a NiFi restart should not be required. Changes
should be auto-detected by a processor in the workflow.
I'd like to ask three related questions.
Q1- If I was to set such parms in the second configuration file, how would
I load those values into attributes that would be associated with each
flowfile handled by my workflow? Can you refer me to an example?
Q2- I'm given to understand that the approach for Q1 would require a
restart of nifi in order to pick up the new values. Is it possible instead
to use an InvokeScriptedProcessor (ISP) in my workflow to do this instead?
I have used ISP to redirect log messages to a log file of my choosing. ISP
permits you to define actions that happen only once at processor start, and
so do not get repeated for each and every flowfile handled by the
processor. I set up logging in this manner now in a python script executed
by ISP:
def initialize(self, context):
try:
self.logger = logging.getLogger(....)
self.logger.setLevel(logging.DEBUG)
except:
....
How can I set attributes - common attributes - inside that initialize()
method that will be inherited by each flowfile passing through my ISP
instance?
I am hoping this is possible, because then edits to a simple text file
will not require a restart of nifi following changes - I will only have to
restart our ISP. And while this is not entirely "hands free" as required by
#R3, it is preferred to disrupting the entire nifi instance with a restart.
Q3- How can I incorporate processors in my workflow to auto-detect a change
in a system file, and reload those system file contents to attributes?
Thanks in advance for your guidance. -Jim
