Add variable width histogram aggregation

search_aggs_bucket_variable_width_histogram.go

@@ -0,0 +1,111 @@
+// Copyright 2012-present Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+// VariableWidthHistogramAggregation is a multi-bucket values source based aggregation
+// that can be applied on numeric values extracted from the documents.
+// It dynamically builds buckets over the values given a target number of buckets.
+// See: https://www.elastic.co/guide/en/elasticsearch/reference/7.17/search-aggregations-bucket-variablewidthhistogram-aggregation.html
+type VariableWidthHistogramAggregation struct {
+	field           string
+	subAggregations map[string]Aggregation
+	meta            map[string]interface{}
+
+	buckets       *int64
+	initialBuffer *int64
+	shardSize     *int64
+}
+
+func NewVariableWidthHistogramAggregation() *VariableWidthHistogramAggregation {
+	return &VariableWidthHistogramAggregation{
+		subAggregations: make(map[string]Aggregation),
+	}
+}
+
+func (a *VariableWidthHistogramAggregation) Field(field string) *VariableWidthHistogramAggregation {
+	a.field = field
+	return a
+}
+
+func (a *VariableWidthHistogramAggregation) Buckets(buckets int64) *VariableWidthHistogramAggregation {
+	a.buckets = &buckets
+	return a
+}
+
+func (a *VariableWidthHistogramAggregation) InitialBuffer(initialBuffer int64) *VariableWidthHistogramAggregation {
+	a.initialBuffer = &initialBuffer
+	return a
+}
+
+func (a *VariableWidthHistogramAggregation) ShardSize(shardSize int64) *VariableWidthHistogramAggregation {
+	a.shardSize = &shardSize
+	return a
+}
+
+func (a *VariableWidthHistogramAggregation) SubAggregation(name string, subAggregation Aggregation) *VariableWidthHistogramAggregation {
+	a.subAggregations[name] = subAggregation
+	return a
+}
+
+// Meta sets the meta data to be included in the aggregation response.
+func (a *VariableWidthHistogramAggregation) Meta(metaData map[string]interface{}) *VariableWidthHistogramAggregation {
+	a.meta = metaData
+	return a
+}
+
+func (a *VariableWidthHistogramAggregation) Source() (interface{}, error) {
+	// Example:
+	// {
+	//     "aggs" : {
+	//         "prices" : {
+	//             "variable_width_histogram" : {
+	//                 "field" : "price",
+	//                 "buckets" : 2
+	//             }
+	//         }
+	//     }
+	// }
+	//
+	// This method returns only the { "variable_width_histogram" : { ... } } part.
+
+	source := make(map[string]interface{})
+	opts := make(map[string]interface{})
+	source["variable_width_histogram"] = opts
+
+	// ValuesSourceAggregationBuilder
+	if a.field != "" {
+		opts["field"] = a.field
+	}
+
+	if a.buckets != nil {
+		opts["buckets"] = *a.buckets
+	}
+	if a.initialBuffer != nil {
+		opts["initial_buffer"] = *a.initialBuffer
+	}
+	if a.shardSize != nil {
+		opts["shard_size"] = *a.shardSize
+	}
+
+	// AggregationBuilder (SubAggregations)
+	if len(a.subAggregations) > 0 {
+		aggsMap := make(map[string]interface{})
+		source["aggregations"] = aggsMap
+		for name, aggregate := range a.subAggregations {
+			src, err := aggregate.Source()
+			if err != nil {
+				return nil, err
+			}
+			aggsMap[name] = src
+		}
+	}
+
+	// Add Meta data if available
+	if len(a.meta) > 0 {
+		source["meta"] = a.meta
+	}
+
+	return source, nil
+}

search_aggs_bucket_variable_width_histogram_test.go

@@ -0,0 +1,44 @@
+// Copyright 2012-present Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestVariableWidthHistogramAggregation(t *testing.T) {
+	agg := NewVariableWidthHistogramAggregation().Field("price").Buckets(50)
+	src, err := agg.Source()
+	if err != nil {
+		t.Fatal(err)
+	}
+	data, err := json.Marshal(src)
+	if err != nil {
+		t.Fatalf("marshaling to JSON failed: %v", err)
+	}
+	got := string(data)
+	expected := `{"variable_width_histogram":{"buckets":50,"field":"price"}}`
+	if got != expected {
+		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
+	}
+}
+
+func TestVariableWidthHistogramAggregationWithMetaData(t *testing.T) {
+	agg := NewVariableWidthHistogramAggregation().Field("price").InitialBuffer(100).ShardSize(500).Meta(map[string]interface{}{"name": "Oliver"})
+	src, err := agg.Source()
+	if err != nil {
+		t.Fatal(err)
+	}
+	data, err := json.Marshal(src)
+	if err != nil {
+		t.Fatalf("marshaling to JSON failed: %v", err)
+	}
+	got := string(data)
+	expected := `{"meta":{"name":"Oliver"},"variable_width_histogram":{"field":"price","initial_buffer":100,"shard_size":500}}`
+	if got != expected {
+		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
+	}
+}