Reindex specific indices in ES administration

Summary

This is a follow-up to !17230 (closed) / !18254 (merged) / !20421 (merged).

Currently the UI has a global Reindex button, which queues a reindexing job that forwards indexing requests to all configured ES indices.

We want to add a way to only reindex a specific index, to avoid putting load on an existing ES index when adding a second one (for e.g. migration purposes).

Note: "Reindexing" currently doesn't involve deleting existing ES documents, and will just try to index any missing data.

Improvements

  • Refactor the involved backend services to limit indexing to a specific index.
    • It's not clear yet how to do this, because our application-level code is "blind" to our gem-level multi-version proxies.
  • Extend the /elasticsearch_indices/reindex API endpoint to accept an ID for an ES index.
  • Enable the per-index Start indexing button in the frontend, and pass the index ID to the API.
    • The button was already implemented in !20421 (merged), but is commented out.

Involved components

  • ee/app/assets/javascripts/elasticsearch/components/es_index_actions.vue
  • ee/app/services/elastic/index_projects_service.rb
  • ee/lib/api/elasticsearch_indices.rb
Edited by Markus Koller