Reindex after resuming indexing in ES administration

Summary

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

When resuming ES indexing, the user usually wants to reindex to cover any indexing gaps since ES indexing has been paused.

Improvements

In the backend, we need to accept a flag in the /elasticsearch/toggle_indexing endpoint, and if necessary queue a reindexing job after indexing has been enabled.

In the frontend, this should be implemented as in the proposed designs:

image

There's a small change in wording though: Indexing is resumed before queueing the indexing job, at least with our current architecture.

Involved components

  • ee/app/assets/javascripts/elasticsearch/components/es_index_actions.vue
    • The code for this already exists, but is commented out.
  • ee/lib/api/elasticsearch_indices.rb