Resilience for batch indexing

[pandu-k]

Add_docs calls should be resilient for batch indexing.

There should be a variable in add_documents, where you can pass a function to deal with errors.

This function will have this structure:

def error_handler(Exception):
     # your code here. Perhaps raise for certain types of error, add errors to your custom log object etc.

add_docs call:

my_index.add_documents(docs=docs, error_handler=retry_on_429s)

[pandu-k]

We can have inbuilt functions, that can be used, if customers don't want to write their own. For example:

my_index.add_documents(docs=docs, error_handler=mq.error_handlers.ignore_429)

[vicilliar]

In the handlers, it could be a good idea to have configurable parameters like time_to_retry and max_retries if the user wants to set them too