The cat API previously used the Content-Type header field for
determining the media type of the response. This is in opposition to the
HTTP spec which specifies the Accept header field for this purpose. This
commit replaces the use of the Content-Type header field with the Accept
header field in the cat API.
Closes#14421
If we want to have a full picture of versions running in a cluster, we need to add a `_cat/plugins` endpoint.
Response could look like:
```sh
% curl es2:9200/_cat/plugins?v
node component version type url desc
es1 mapper-attachments 1.7.0 j Adds the attachment type allowing to parse difference attachment formats
es1 lang-javascript 1.4.0 j JavaScript plugin allowing to add javascript scripting support
es1 analysis-smartcn 1.9.0 j Smart Chinese analysis support
es1 marvel 1.1.0 j/s http://localhost:9200/_plugins/marvel Elasticsearch Management & Monitoring
es1 kopf 0.5.3 s http://localhost:9200/_plugins/kopf kopf - simple web administration tool for ElasticSearch
es2 mapper-attachments 2.0.0.RC1 j Adds the attachment type allowing to parse difference attachment formats
es2 lang-javascript 2.0.0.RC1 j JavaScript plugin allowing to add javascript scripting support
es2 analysis-smartcn 2.0.0.RC1 j Smart Chinese analysis support
```
Closes#4824.
By default active, rejected and queue thread statistics are included for the index, bulk and search thread pool.
Other thread statistics of other thread pools can be included via the `h` query string parameter.
Closes#4907
Andrej Kazakov
Yannick Welsch
Dave Parfitt
Clinton Gormley
Alexander Reelsen
Christoph Büscher
javanna
Lee Hinman
David Pilato
Andrew Raines
Martijn van Groningen
Shay Banon