Allow plugin removal with full name, or represent plugin list differently

[jaymode]

Filing on behalf of @markwalkom

Elasticsearch version: 5.0.0-beta1

Plugins installed: x-pack

Description of the problem including expected versus actual behavior:
The output of the plugin list command can be counter-intuitive for users looking to remove a plugin:

Current Output:

root@elastic5:~# /usr/share/elasticsearch/bin/elasticsearch-plugin list
x-pack@5.0.0-beta1
root@elastic5:~# /usr/share/elasticsearch/bin/elasticsearch-plugin remove x-pack@5.0.0-beta1
-> Removing x-pack@5.0.0-beta1...
A tool for managing installed elasticsearch plugins

Commands
--------
list - Lists installed elasticsearch plugins
install - Install a plugin
remove - Removes a plugin from elasticsearch

Non-option arguments:
command

Option         Description
------         -----------
-h, --help     show help
-s, --silent   show minimal output
-v, --verbose  show verbose output
ERROR: plugin x-pack@5.0.0-beta1 not found; run 'elasticsearch-plugin list' to get list of installed plugin

Users should be able to remove plugins using the displayed, long name, ie x-pack@5.0.0-beta1, or we should have a columnar representation of the plugins like:

root@elastic5:~# /usr/share/elasticsearch/bin/elasticsearch-plugin list
Name     Version
x-pack    x-pack@5.0.0-beta1

[dadoonet]

For the record, this has been introduced by #18683

[colings86]

Discussed in FixItFriday and we felt that we should use the columnar output for the list command but not prepend the version with the plugin name, so the output would look like:

root@elastic5:~# /usr/share/elasticsearch/bin/elasticsearch-plugin list
Name     Version
x-pack    5.0.0-beta1

We should make sure this change is also made in kibana and logstash so the output is consistent across all three

[dadoonet]

Sorry was not in FixItFriday today and missed that discussion. I wonder if we should be consistent with the _cat API? I mean having optional headers, and by default don't display the version so we keep the previous rendering which is super easy to consume by a shell script and let the users ask for more details with the verbose option?

[jasontedor]

@colings86 The reason we are here is because of #18683 which wanted a machine-readable format for this output. I'm not sure if the whitespace satisfies that request or not; I'm not sure if we, for example, enforce that the name and version do not contain spaces. We previously discussed #18683 in an earlier Fix-it-Friday; I was against that change because it's conflating a human-readable API with a machine-readable API.

[colings86]

@jasontedor Ok, thanks for giving more background. I have removed adoptme and marks as discuss again as there is obviously more that we need to work out here before we implement/don't implement this change

[rjernst]

I also was against the change in #18683. I think it should be reverted. I dont' think we should complicate the plugin tool anymore. We have a verbose option for the extra information. As I explained in that issue, having the version does not actually help with "automating". When elasticsearch is upgraded, all plugins must be upgraded.