[BUG] Malfunctioning/confusing/redundant Index template method

[wbeckler]

The Go client contains two methods for using index templates. One of them, opensearchapi.IndicesPutTemplateRequest, uses a nonexistent legacy REST API (/_template).

In OpenSearch v1.x and v2.x the correct REST API is /_index_template, which is accessible by the correct method opensearchapi.IndicesPutIndexTemplateRequest.

I would propose we remove the legacy method, which is confusing and points to an unsupported API.

[dblock]

Deprecate the method in a minor release and remove in major.

[wbeckler]

Would we consider this to be a "breaking" change rather than a bugfix if the method points to a nonexistent API in OpenSearch?

[dblock]

So the method never worked (aka produced an error)? If so removing it is fine as a bugfix.

[Jakob3xD]

FYI: The _template still exists and is also working in Opensearch 2.6.0.
Therefore it is deprecated but still a valid way to do templating.

[whym9]

If this issue is still relevant, I would like to solve it.

[Jakob3xD]

@whym9 how is this issue affecting you?

As already mentioned both APIs still exist and both work. I personally don´t see this as a bug. IMO we should add some sort of deprecation warning/comment to the request type linking/referring to the request type for the _index_template api. We should remove this once the API get removed from Opensearch it self. Otherwise we reduce the Opensearch api support.
WDYT @wbeckler

[tannerjones4075]

If this issue is still relevant, I would like to solve it.

[VachaShah]

Thank you @tannerjones4075! Assigning this to you.

[tannerjones4075]

This issue can be closed because the issue has been resolved: #390