github.com/khulnasoft/elasticsearch

elasticsearch

A non-obtrusive, idiomatic and easy-to-use query and aggregation builder for the official Go client for ElasticSearch.

Table of Contents

• Description
• Status
• Installation
• Usage
• Notes
• Features
  • Supported Queries
  • Supported Aggregations
  • Custom Queries and Aggregations
• License

Description

elasticsearch alleviates the need to use extremely nested maps (map[string]interface{}) and serializing queries to JSON manually. It also helps eliminating common mistakes such as misspelling query types, as everything is statically typed.

Using elasticsearch can make your code much easier to write, read and maintain, and significantly reduce the amount of code you write. Wanna know how much code you'll save? just check this project's tests.

Status

This is an early release, API may still change.

Installation

elasticsearch is a Go module. To install, simply run this in your project's root directory:

go get github.com/khulnasoft/elasticsearch

Usage

elasticsearch provides a method chaining-style API for building and executing queries and aggregations. It does not wrap the official Go client nor does it require you to change your existing code in order to integrate the library. Queries can be directly built with elasticsearch, and executed by passing an *elasticsearch.Client instance (with optional search parameters). Results are returned as-is from the official client (e.g. *esapi.Response objects).

Getting started is extremely simple:

package main

import (
	"context"
	"log"

	"github.com/khulnasoft/elasticsearch"
	"github.com/elastic/go-elasticsearch/v7"
)

func main() {
    // connect to an ElasticSearch instance
    es, err := elasticsearch.NewDefaultClient()
    if err != nil {
        log.Fatalf("Failed creating client: %s", err)
    }

    // run a boolean search query
    res, err := elasticsearch.Search().
        Query(
            elasticsearch.
                Bool().
                Must(elasticsearch.Term("title", "Go and Stuff")).
                Filter(elasticsearch.Term("tag", "tech")),
        ).
        Aggs(
            elasticsearch.Avg("average_score", "score"),
            elasticsearch.Max("max_score", "score"),
        ).
        Size(20).
        Run(
            es,
            es.Search.WithContext(context.TODO()),
            es.Search.WithIndex("test"),
        )
        if err != nil {
            log.Fatalf("Failed searching for stuff: %s", err)
        }

    defer res.Body.Close()

    // ...
}

Notes

• elasticsearch currently supports version 7 of the ElasticSearch Go client.
• The library cannot currently generate "short queries". For example, whereas ElasticSearch can accept this:

{ "query": { "term": { "user": "Kimchy" } } }

The library will always generate this:

{ "query": { "term": { "user": { "value": "Kimchy" } } } }

This is also true for queries such as "bool", where fields like "must" can either receive one query object, or an array of query objects. elasticsearch will generate an array even if there's only one query object.

Features

Supported Queries

The following queries are currently supported:

ElasticSearch DSL	elasticsearch Function
"match"	Match()
"match_bool_prefix"	MatchBoolPrefix()
"match_phrase"	MatchPhrase()
"match_phrase_prefix"	MatchPhrasePrefix()
"match_all"	MatchAll()
"match_none"	MatchNone()
"multi_match"	MultiMatch()
"exists"	Exists()
"fuzzy"	Fuzzy()
"ids"	IDs()
"prefix"	Prefix()
"range"	Range()
"regexp"	Regexp()
"term"	Term()
"terms"	Terms()
"terms_set"	TermsSet()
"wildcard"	Wildcard()
"bool"	Bool()
"boosting"	Boosting()
"constant_score"	ConstantScore()
"dis_max"	DisMax()

Supported Aggregations

The following aggregations are currently supported:

ElasticSearch DSL	elasticsearch Function
"avg"	Avg()
"weighted_avg"	WeightedAvg()
"cardinality"	Cardinality()
"max"	Max()
"min"	Min()
"sum"	Sum()
"value_count"	ValueCount()
"percentiles"	Percentiles()
"stats"	Stats()
"string_stats"	StringStats()
"top_hits"	TopHits()
"terms"	TermsAgg()

Supported Top Level Options

The following top level options are currently supported:

ElasticSearch DSL	elasticsearch.Search Function
"highlight"	Highlight()
"explain"	Explain()
"from"	From()
"postFilter"	PostFilter()
"query"	Query()
"aggs"	Aggs()
"size"	Size()
"sort"	Sort()
"source"	SourceIncludes(), SourceExcludes()
"timeout"	Timeout()

Custom Queries and Aggregations

To execute an arbitrary query or aggregation (including those not yet supported by the library), use the CustomQuery() or CustomAgg() functions, respectively. Both accept any map[string]interface{} value.

License

This library is distributed under the terms of the Apache License 2.0.