Get rollup index capabilities API

GET <target>/_rollup/data

A single rollup index may store the data for multiple rollup jobs, and may have a variety of capabilities depending on those jobs.

This API will allow you to determine:

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 stores its data in sensor_rollup:

PUT _rollup/job/sensor
{
  "index_pattern": "sensor-*",
  "rollup_index": "sensor_rollup",
  "cron": "*/30 * * * * ?",
  "page_size": 1000,
  "groups": {
    "date_histogram": {
      "field": "timestamp",
      "fixed_interval": "1h",
      "delay": "7d"
    },
    "terms": {
      "fields": [ "node" ]
    }
  },
  "metrics": [
    {
      "field": "temperature",
      "metrics": [ "min", "max", "sum" ]
    },
    {
      "field": "voltage",
      "metrics": [ "avg" ]
    }
  ]
}

If at a later date, we’d like to determine what jobs and capabilities were stored in the sensor_rollup index, we can use the get rollup index API:

response = client.rollup.get_rollup_index_caps(
  index: 'sensor_rollup'
)
puts response

GET /sensor_rollup/_rollup/data

Note how we are requesting the concrete rollup index name (sensor_rollup) as the first part of the URL. This will yield the following response:

{
  "sensor_rollup" : {
    "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",
              "fixed_interval" : "1h",
              "delay": "7d"
            }
          ],
          "voltage" : [
            {
              "agg" : "avg"
            }
          ]
        }
      }
    ]
  }
}

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 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.

Like other APIs that interact with indices, you can specify index patterns instead of explicit indices:

response = client.rollup.get_rollup_index_caps(
  index: '*_rollup'
)
puts response

GET /*_rollup/_rollup/data