What is the difference between DoFn.Setup and DoFn.StartBundle?

Question

What is the difference between these two annotations?

DoFn.Setup Annotation for the method used to prepare the instance for processing element packages.

Uses the word bundle, takes zero arguments.

DoFn.StartBundle Annotation for the method used to prepare an instance for processing a batch of elements.

Uses the word "package", takes zero or one argument ( StartBundleContext, access method to PipelineOptions).

What am i trying to do

I need to initialize a library in an instance of DoFn, and then use this library for each item in a package or package. I wouldn’t tear my hair with these two words, but maybe there’s some difference in the conveyor belt?

Answer 1

DoFn :

• Setup
• :
  • StartBundle
  • ProcessElement
  • FinishBundle
• Teardown

.. DoFn ( ) , ( ) .

Setup/Teardown StartBundle/FinishBundle - DoFn ProcessElement, . :

• , , RPC , RPC N . StartBundle/FinishBundle , FinishBundle: FinishBundle FinishBundle FinishBundle ( StartBundle / ). , , - , , , FinishBundle , ( ), , ; "" .
• , . StartBundle/FinishBundle, , , , . , Setup Teardown.
• DoFn, , .. Setup.

:

• Setup/Teardown.
• StartBundle/FinishBundle.

( , / )

DoFn, .