I got 2 indices.
say index1 and index2.
When I index a new document in index2, I want some fields to be copied from the document in index1 having the same _id.
I previously realized this using logstash + the elasticsearch filter.
But this time, i'm not using logstash. I index documents in index2 using the bulk api.
What is the best way to achieve that ? Ingestion plugin ?