es-eql

Elasticsearch Easy Query Builder

Builds simple Elasticsearch queries using standard programming syntax. Not all queries that can be expressed in Elasticsearch are possible, but those that are possible are simple to write. This can be used to expose Elasticsearch queries to a moderately technical user with little extra training.

Installation

es-eql is your typical NPM package.

npm install --save es-eql

Usage

A basic example

import * as elasticsearch from "elasticsearch";
import * as eseql from "es-eql";

const es = new elasticsearch.Client({
    apiVersion: "5.1",
    hosts: "myhostname"
});

es.search({
    index: "myindex",
    type: "mytype",
    body: eseql.buildElasticsearchQuery("environment == 'production' && (tag == 'http' || tag == 'ftp')")
}).then(result => {
    console.log("search result", result.hits.hits.map(d => d._source));
}, error => {
    console.log("search error", error);
});

Writing easy queries

The following operators are supported:

symbol	operation
()	operation grouping
!	logical negation
&&	logical and
||	logical or
==	logical equals
!=	logical not equals
*=	wildcard match
!*=	wildcard not match
~=	fuzzy match
!~=	fuzzy not match
<	less than
<=	less than or equals
>	greater than
>=	greater than or equals

All comparison operators must work against a literal value. For example threat.level > 5 and flavor == 'chocolate' are valid. flavor == color is not valid because Elasticsearch does not allow comparing values within a document.

Existence of a field can be required with the field name and no operator (JavaScript-style truthiness). Non existence of a field can be required by negating the field. eg: environment, !environment.

Field verification

buildElasticsearchQuery accepts an options param that can verify whether a field name is valid.

eg:

const options = {
    fieldVerifier: function (field) {
       switch (field) {
           case "x":
           case "z.a":
           case "z.b":
           case "z.c":
               return true;
       }
       return false;
   }
};

// valid
eseql.buildElasticsearchQuery("x == 1", options);    
eseql.buildElasticsearchQuery("z.a == 1 && z.b != -2", options);

// invalid
eseql.buildElasticsearchQuery("y == 9", options);