este

esta

The Simplest ElasticSearch Node.js Module

Guide to esta Documentation

Usage:

• Installation
• CONNECT to ElasticSearch Cluster
• CRUD
  • CREATE (Save) a (new) record
  • READ a record
  • UPDATE an (existing) record
  • DELETE a record
• SEARCH for Record(s)
• STATS
• Error handling
• Local/Dev Machine
• (Travis) CI
• (Optional) Use Vagrant to Run ElasticSearch

Philosophy / Background / Detail:

• Only Core Modules
  • Dev Dependencies
• Code Quality
• Contributing
• Module Name
• License

## Usage

Installation

### Install from [NPM](https://www.npmjs.com/package/esta)

npm install esta --save

#### CONNECT to ElasticSearch Cluster > ES.CONNECT(calback(response))

If you need to check the connection status to the ElasticSearch Instance/Cluster we expose the handy ES.CONNECT method:

var ES = require('esta');
 
ES.CONNECT(function (response) {
  console.log(response);
  // for more detailed stats see: STATS method below
});

example ES.CONNECT response:

{ status: 200,
  name: 'Ultragirl',
  cluster_name: 'elasticsearch',
  version:
   { number: '1.4.2',
     build_hash: '927caff6f05403e936c20bf4529f144f0c89fd8c',
     build_timestamp: '2014-12-16T14:11:12Z',
     build_snapshot: false,
     lucene_version: '4.10.2' },
  tagline: 'You Know, for Search' }

Note: Esta expects you to have environment variables set up for ES_HOST and ES_PORT (see below)

###[CRUD](http://en.wikipedia.org/wiki/Create,_read,_update_and_delete) Methods #### CREATE (Save) a (new) record > ES.CREATE(record, callback(response))

Creating a new record is easy:

// define the record you want to store:
var record = {
  index: 'twitter',
  type: 'tweet',
  id: Math.floor(Math.random() * (100000)), // or what ever GUID you want
  message: 'Your amazing message goes here'
};
ES.CREATE(record, function(response) {
 // do what ever you like with the response
});

A typical successful ES.CREATE response:

{ _index: 'twitter',
  _type: 'tweet',
  _id: '112669114721',
  _version: 1,
  created: true }

Required Fields for a New Record:

• index can be compared to a Database in SQL see: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/glossary.html#glossary-index
• type is like the table in SQL-world or a collection in other NoSQL systems. see: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/glossary.html#glossary-type
• id is the unique key for your record. equivalent to the primary-key in a SQL-world

#### READ a record > ES.READ(record, callback(response))

READing your record:

// define the record you want to retrieve:
var record = {
  index: 'twitter',
  type: 'tweet',
  id: 1234, // or what ever GUID you want to lookup
};
ES.READ(record, function(response) {
 // do what ever you like with the response
});

A typical successful ES.READ response:

{ _index: 'twitter',
  _type: 'tweet',
  _id: '735981868114',
  _version: 1,
  found: true,
  _source: { message: 'My Awesome Message' }
}

Here _source is the original data you inserted as the record.

Record NOT Found

When a record does not exist response.found is false. e.g:

{ _index: 'twitter',
  _type: 'tweet',
  _id: '804164689732',
  found: false }

Required Fields for a READing a Record

• index we need to know which "database" our record is in
• type "table"
• id the unique key for the record you are looking up.

#### UPDATE an (existing) record > ES.UPDATE(record, callback(response))

UPDATE an existing record:

// define the record you want to store:
var record = {
  index: 'twitter',
  type: 'tweet',
  id: 1234, // or what ever GUID you want
  message: 'Revised message'
};
ES.UPDATE(record, function(response) {
 // do what ever you like with the response
});

A typical successful ES.UPDATE response:

{ _index: 'twitter',
  _type: 'tweet',
  _id: '639403095701',
  _version: 2,
  created: false }

Notice how the _version gets incremented to 2

Required Fields for a Updating an Existing Record:

• index we need to know which "database" our record is in
• type "table"
• id the unique key for the record you are updating.

Note: UPDATE actually performs an UPSERT
UPdate record if already exists or inSERT (create) if its new.

#### DELETE a record > ES.DELETE(record, callback(response))

// define the record you want to store:
var record = {
  type: 'tweet',
  index: 'twitter',
  id: 1234, // or what ever GUID you want
  message: 'Revised message'
};
ES.DELETE(record, function(response) {
 // do what ever you like with the response
});

A typical successful ES.DELETE response:

{ found: true,
  _index: 'twitter',
  _type: 'tweet',
  _id: '137167415115',
  _version: 2,
  deleted: true }

Notice how the deleted is true

Required Fields for a Deleting an Existing Record:

• index we need to know which "database" our record is in
• type "table"
• id the unique key for the record you are updating.

Obviously if the record is NOT Found, there is nothing to delete. In that case, the response look like this: (found is false)

{ found: false,
  _index: 'twitter',
  _type: 'tweet',
  _id: '951078315032',
  _version: 1 }

### SEARCH for Record(s) > ES.SEARCH(query, callback(response))

Searching is super easy:

// setup query:
var query = {
  index: 'twitter',
  type:  'tweet',
  field: 'text',     // the field we want to search in
  text:  'amazing'   // string we are searching for
};
 
SEARCH(query, function(response) {
  // console.log(res);
  t.equal(res.hits.total > 0, true,
    chalk.green("✓ Search results found: "+ res.hits.total));
  t.end();
});

A typical successful ES.SEARCH response:

{ took: 8,
  timed_out: false,
  _shards: { total: 5, successful: 5, failed: 0 },
  hits:
   { total: 924,
     max_score: 0.6355637,
     hits:
      [ [Object],
        [Object],
        etc...
  }
}

The response.hits.total is 924 (the number of records that matched our SEARCH query)

Required Fields for a SEARCHing:

• index we need to know which "database" our record is in
• type "table"
• field the field in the record you want to search in.
• text the text you are searching for.

When NO RECORDS are FOUND the response will look this:

{ took: 2,
  timed_out: false,
  _shards: { total: 5, successful: 5, failed: 0 },
  hits: { total: 0, max_score: null, hits: [] } }

We check for if(response.hits.total > 0) { /* use/display results */ } else { /* show sad face */}
Here's the image we use:

### STATS > ES.STATS(callback(response))

The ES.STATS method exposes the ElasticSearch Instance/Cluster _stats see: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/indices-stats.html

STATS(function (response) {
  // do something awesome response
});

ElasticSearch returns rich information on cluster health, document count etc. see: #31 for complete STATS output

### Error Handling

Warning: Contains Opinion (based on experience)

Most of the Node.js developers I've worked with, don't handle errors well.
A typical (bad) example:

if(error) {
  console.log(error); // this is worse than useless!
}

So instead of having of having code full of if(err) ... we have deliberately cut out errors from callback functions completely.

Thus, all the methods in this module have the simplified signature:

ES.METHOD(record, function(response){
  // do something with response
});

Instead, we propose using a central error catcher. e.g:

process.on('uncaughtException', function(err) {
  console.log('ERROR: ' + err); // preferably handle errors appropriately
});

or, if you are using Hapi.js use https://github.com/hapijs/poop

For more on Errors, please read: https://www.joyent.com/developers/node/design/errors

Required: Use Environment Variables for HOST & PORT

We need to move away from using config files.
Read: http://12factor.net/config (Store config in the environment - no more config.json!)

### Local/Dev Machine

To use environment variables for HOST & PORT on your local machine: you will need to run the following Shell Commands:

export ES_HOST="127.0.0.1"
export ES_PORT=9200

### (Travis) CI

Sample .travis.yml file:

language: node_js
node_js:
  - 0.10
services:
  - elasticsearch
env:
  - ES_HOST="127.0.0.1" ES_PORT=9200

if you are new to Travis-CI see: https://github.com/docdis/learn-travis

## (*Optional*) Use *Vagrant* to Run ElasticSearch [](https://github.com/nelsonic/learn-vagrant)

If, like me you prefer not to have Java running on your dev machine (because its chronically insecure) I highly recommend using Vagrant to run a light-weight virtual machine to isolate ElasticSearch and only install Java in the VM.

The other obvious benefit of using Vagrant is that all your fellow developers will have exactly the same (latest) build so there's no risk of version incompatibility. Learn more at: https://github.com/nelsonic/learn-vagrant

I've included a Vagrantfile in this repo which will get you up-and-running with Ubuntu, Node.js & ElasticSearch with a single command: vagrant up

If you have any questions, just ask!

Philosophy / Background / Detail

Why Create a New Library?

We wanted something simpler.
Easier to understand (under 300 lines of code!) and thus much easier to extend if you need to!

Practical Feature: Recover Accidentally Deleted Data

We wanted a way of "soft-deleting" records (i.e. avoiding data loss.) If you like the idea of being able to * recover accidentally deleted data*, you will love our DELETE method see: lib/delete.js

## *Only* Core Modules [](https://david-dm.org/nelsonic/esta)

Zero external dependencies (3rd party modules).

There are quite a few modules in the node ecosystem for use with ElasticSearch. However, when I saw how many dependencies the "Official" ElasticSearch Node.js Module https://github.com/elasticsearch/elasticsearch-js had and especially the number of DevDependencies, it made it hard to contribute to the project...

Our aim is to build something that only uses core modules with Stable APIs, so we never have to think about upgrading - it also makes it a lot easier for others to learn how the module works, which invites contribution from the community.
Given that ElasticSearch has a REST API we are only using Node's http (core) module. and this is kept DRY (only in one file) see: lib/http_request.js

### Dev Dependencies [](https://david-dm.org/nelsonic/esta#info=devDependencies)

We carefully select and only use well-maintained "pure" JavaScript modules in our development toolchain:

• Tape for testing: https://github.com/substack/tape
• Istanbul for Code Coverage: https://github.com/nelsonic/learn-istanbul
• Chalk for colors in test output (readability)
• Pre-commit for ensuring all commits pass strict quality checks before being pushed to GitHub. see: https://github.com/nelsonic/learn-pre-commit
• jshint checks code style is consistent: https://github.com/nelsonic/learn-jshint
• CodeClimate for tracking code quality and test coverage: https://github.com/nelsonic/learn-codeclimate

## Code Quality [](https://travis-ci.org/nelsonic/esta) [](https://codeclimate.com/github/nelsonic/esta) [](https://codeclimate.com/github/nelsonic/esta)

If you are looking for a module you can trust, these are the "badges" you are looking for.

## Contributing [](https://github.com/nelsonic/esta/fork)

All contributions are welcome.
If anything is unclear please create an issue: https://github.com/nelsonic/esta/issues

ALLCAPS MEHTOD NAMES?

We prefer to have the METHOD names UPPERCASE because it makes them easy to spot and differentiate from your code. If you feel they are a bit "shouty" all methods are available in lowercase too; take your pick! see: http://git.io/pZ6t

## Module Name

The choice of module name was the answer to the question:

Q: Which ElasticSearch Node Module should I use...?
A: https://translate.google.com/#auto/en/esta

## License

MIT