[role="xpack"]
[testenv="basic"]
[[rollup-get-rollup-caps]]
=== Get Rollup Job Capabilities
++++
<titleabbrev>Get Rollup Caps</titleabbrev>
++++

experimental[]

This API returns the rollup capabilities that have been configured for an index or index pattern.  This API is useful
because a rollup job is often configured to rollup only a subset of fields from the source index.  Furthermore, only
certain aggregations can be configured for various fields, leading to a limited subset of functionality depending on
that configuration.

This API will allow you to inspect an index and determine:

1. Does this index have associated rollup data somewhere in the cluster?
2. If yes to the first question, what fields were rolled up, what aggregations can be performed, and where does the data
live?

==== Request

`GET _xpack/rollup/data/{index}`

//===== Description

==== Path Parameters

`index`::
  (string) Index, indices or index-pattern to return rollup capabilities for.  `_all` may be used to fetch
  rollup capabilities from all jobs


==== Request Body

There is no request body for the Get Rollup Caps API.

==== Authorization

You must have `monitor`, `monitor_rollup`, `manage` or `manage_rollup` cluster privileges to use this API.
For more information, see
{xpack-ref}/security-privileges.html[Security Privileges].

==== Examples

Imagine we have an index named `sensor-1` full of raw data.  We know that the data will grow over time, so there
will be a `sensor-2`, `sensor-3`, etc.  Let's create a Rollup job that targets the index pattern `sensor-*` to accommodate
this future scaling:

[source,js]
--------------------------------------------------
PUT _xpack/rollup/job/sensor
{
    "index_pattern": "sensor-*",
    "rollup_index": "sensor_rollup",
    "cron": "*/30 * * * * ?",
    "page_size" :1000,
    "groups" : {
      "date_histogram": {
        "field": "timestamp",
        "interval": "1h",
        "delay": "7d"
      },
      "terms": {
        "fields": ["node"]
      }
    },
    "metrics": [
        {
            "field": "temperature",
            "metrics": ["min", "max", "sum"]
        },
        {
            "field": "voltage",
            "metrics": ["avg"]
        }
    ]
}
--------------------------------------------------
// CONSOLE
// TEST[setup:sensor_index]

We can then retrieve the rollup capabilities of that index pattern (`sensor-*`) via the following command:

[source,js]
--------------------------------------------------
GET _xpack/rollup/data/sensor-*
--------------------------------------------------
// CONSOLE
// TEST[continued]

Which will yield the following response:

[source,js]
----
{
  "sensor-*" : {
    "rollup_jobs" : [
      {
        "job_id" : "sensor",
        "rollup_index" : "sensor_rollup",
        "index_pattern" : "sensor-*",
        "fields" : {
          "node" : [
            {
              "agg" : "terms"
            }
          ],
          "temperature" : [
            {
              "agg" : "min"
            },
            {
              "agg" : "max"
            },
            {
              "agg" : "sum"
            }
          ],
          "timestamp" : [
            {
              "agg" : "date_histogram",
              "time_zone" : "UTC",
              "interval" : "1h",
              "delay": "7d"
            }
          ],
          "voltage" : [
            {
              "agg" : "avg"
            }
          ]
        }
      }
    ]
  }
}
----
// TESTRESPONSE

The response that is returned contains information that is similar to the original Rollup configuration, but formatted
differently.  First, there are some house-keeping details: the Rollup job's ID, the index that holds the rolled data,
the index pattern that the job was targeting.

Next it shows a list of fields that contain data eligible for rollup searches.  Here we see four fields: `node`, `temperature`,
`timestamp` and `voltage`.  Each of these fields list the aggregations that are possible.  For example, you can use a min, max
or sum aggregation on the `temperature` field, but only a `date_histogram` on `timestamp`.

Note that the `rollup_jobs` element is an array; there can be multiple, independent jobs configured for a single index
or index pattern.  Each of these jobs may have different configurations, so the API returns a list of all the various
configurations available.

We could also retrieve the same information with a request to `_all`:

[source,js]
--------------------------------------------------
GET _xpack/rollup/data/_all
--------------------------------------------------
// CONSOLE
// TEST[continued]

But note that if we use the concrete index name (`sensor-1`), we'll retrieve no rollup capabilities:

[source,js]
--------------------------------------------------
GET _xpack/rollup/data/sensor-1
--------------------------------------------------
// CONSOLE
// TEST[continued]

[source,js]
----
{

}
----
// TESTRESPONSE

Why is this?  The original rollup job was configured against a specific index pattern (`sensor-*`) not a concrete index
(`sensor-1`).  So while the index belongs to the pattern, the rollup job is only valid across the entirety of the pattern
not just one of it's containing indices.  So for that reason, the Rollup Capabilities API only returns information based
on the originally configured index name or pattern.
