I would like to reindex a very big index.
When I run reindex API with elasticsearchjs client I will receive the requestTimeout error, or Gateway timeout error.
It's ok because the reindex process is still running in Elastic server. However, what I want to do is after the reindex finish with full data, I will execute another task.
The question is how can I know the reindex succeeded to run other task?
What is the best practice for this use case?