Specify the index for App Search to use

We have an existing ES index and now want to self-host AppSearch to manage it, but I can't find a way to tell AppSearch to use our existing index. It just creates a new index using a random Guid in the name and forces us to work with that index. According to another post here, someone suggested this isn't possible. So AppSearch requires that you dump your existing index and create a new one from scratch?? How does that make any sense? I can't believe that is the reality. It makes self-hosted AppSearch more of a learning tool than something you could actually use in production.

Here is the other post:

Hi Brian,

This is correct. App Search creates its own indices in Elasticsearch. We currently do not support "choosing" an existing Elasticsearch index to be the source of an engine's data. It is something we're interested in building, but at the moment there are no plans to do so.

In order to use the same data, you will need to re-index that data into App Search. You may find one of our API search clients helpful in order to index the data.

I hope this helps!