Simplify nodes stats API

[spinscale]

First, this breaks backwards compatibility!

• Removed /_cluster/nodes/stats endpoint
• Excpect the stats types not as parameters, but as part of the URL
• Returning all indices stats by default, returning all nodes stats by default
• Supporting groups & types in nodes stats now as well
• Updated documentation & tests accordingly

Closes #4057

[kimchy]

LGTM, I would love @clintongormley to try it out as well...

[clintongormley]

Heya

This doesn't seem to support the indices-metrics, eg:

/_nodes/stats/indices/indexing

Also doesn't support the level parameter

[spinscale]

Fixed the indices metrics.

Regarding supporting the level parameter: The aggregation of information happens to early right now, preventing the stats from being returned per shard at all (for the curious: InternalIndicesService.stats() loops through the index shards and aggregates there already.

Requires some refactoring around the NodeIndicesStats class to support shard level stats and aggregate them later.

[spinscale]

@clintongormley added the level parameter for "indices" and "shards", however "cluster" does not make a lot of sense in a response, which is per node...

will squash it into one commit after review

[clintongormley]

True... perhaps should be node, indices, shards ?

[spinscale]

I like it, wait with reviewing, will put that in first

[bleskes]

Hi,

I've had a quick look to see how things will impact the cluster stats end point I work on now. Things look good from that perspective (it will even allow for removing some code in the cluster stats end point).

Two comments:

• the indices stats API return the index level stats both if level=indices (default) & level=shards , which is different than here.
• Wording wise - level=indices implies to me a per-index stats (which we don't expose now at all). I like Clint's suggestion of having node (what we do now in 0.90), indices (per index) and shards (per shard).

Perhaps we want to make level multi-valued. If we do so, we allow people to get both aggregates and detailed level if need be.

[spinscale]

@bleskes I will also create the additive behaviour here when the level parameter is specified. Wording wise I will go with node (default as it is right now), indices (per index) and shards

thx for the input

[spinscale]

Pushed to support node, indices and shards as level parameter (documentation still pending) - would be happy about another enduser test