Hierarchical facets with Elasticsearch

documents.yaml

_type: product
category_level0: Books
category_level1: Computers & Technology
category_level2: Network Programming
name: Pro AngularJS

---

_type: product
category_level0: Books
category_level1: Computers & Technology
category_level2: Online Searching
name: ElasticSearch Server Second Edition

---

_type: product
category_level0: Books
category_level1: Arts & Photography
category_level2: Photography & Video
name: Humans of New York

mappings.yaml

product: 
    properties: 
        category_level0:
            type: string
            index: not_analyzed
        category_level1:
            type: string
            index: not_analyzed
        category_level2:
            type: string
            index: not_analyzed
        name:
            type: string

play.sh

#!/bin/bash

export ELASTICSEARCH_ENDPOINT="http://localhost:9200"

# Create indexes

curl -XPUT "$ELASTICSEARCH_ENDPOINT/play" -d '{
    "mappings": {
        "product": {
            "properties": {
                "category_level0": {
                    "type": "string",
                    "index": "not_analyzed"
                },
                "category_level1": {
                    "type": "string",
                    "index": "not_analyzed"
                },
                "category_level2": {
                    "type": "string",
                    "index": "not_analyzed"
                },
                "name": {
                    "type": "string"
                }
            }
        }
    }
}'

# Index documents
curl -XPOST "$ELASTICSEARCH_ENDPOINT/_bulk?refresh=true" -d '
{"index":{"_index":"play","_type":"product"}}
{"category_level0":"Books","category_level1":"Computers & Technology","category_level2":"Network Programming","name":"Pro AngularJS"}
{"index":{"_index":"play","_type":"product"}}
{"category_level0":"Books","category_level1":"Computers & Technology","category_level2":"Online Searching","name":"ElasticSearch Server Second Edition"}
{"index":{"_index":"play","_type":"product"}}
{"category_level0":"Books","category_level1":"Arts & Photography","category_level2":"Photography & Video","name":"Humans of New York"}
'

# Do searches

curl -XPOST "$ELASTICSEARCH_ENDPOINT/_search?pretty" -d '
{
    "size": 0,
    "aggregations": {
        "category": {
            "terms": {
                "field": "category_level0"
            },
            "aggs": {
                "level1": {
                    "terms": {
                        "field": "category_level1"
                    },
                    "aggs": {
                        "level2": {
                            "terms": {
                                "field": "category_level2"
                            }
                        }
                    }
                }
            }
        }
    }
}
'

play.yaml

# Auto generated by Found's Play-tool at 2014-11-13T09:48:45+01:00
version: 0
title: Hierarchical facets with Elasticsearch
description: ""

results.yaml

aggregations: 
  category: 
    buckets: 
      - 
        key: "Books"
        doc_count: 3
        level1: 
          buckets: 
            - 
              key: "Computers & Technology"
              doc_count: 2
              level2: 
                buckets: 
                  - 
                    key: "Network Programming"
                    doc_count: 1
                  - 
                    key: "Online Searching"
                    doc_count: 1
            - 
              key: "Arts & Photography"
              doc_count: 1
              level2: 
                buckets: 
                  - 
                    key: "Photography & Video"
                    doc_count: 1

searches.yaml

size: 0

aggregations: 
    category:
        terms: 
            field: category_level0
        aggs: 
            level1:
                terms: 
                    field: category_level1
                aggs: 
                    level2:
                        terms: 
                            field: category_level2