ElasticSearch

Presented by:
Abuzar Hasan
Arkhitech <http://www.arkhitech.com>

History

Shay Baron


Compass in 2004
ElasticSearch in 2010



Written in Java
Cross-platform
Distributed

Users




StumbleUpon
Mozilla
Github
Foursquare

Features

Distributed and Highly Available Search Engine





Each index is fully sharded with a configurable number of shards
Each shard can have one or more replicas
Read / Search operations performed on either one of the replica
shard
Multi Tenant with Multi Types
Various set of APIs

Features

Document Oriented
No need for upfront schema definition



(Near) Real Time Search
Per-Operation Persistence

Single document level operations are atomic, consistent, isolated
and durable

Features

Built on top of Lucene




Each shard is a fully functional Lucene index
All the power of Lucene easily exposed through simple
configuration / plugins
Independent of file format
Open Source under Apache 2 License

Setting Up Elastic Search

Download ElasticSearch (CentOS)
sudo yum install elasticsearch


Start ElasticSearch Server

elasticsearch -f -D
es.config=/usr/local/Cellar/elasticsearch/0.18.5/config/elasticsear
ch.yml

Setting up ElasticSearch w/
Ruby


The ElasticSearch is not ruby specific so 'tire' gem helps ruby
based projects to communicate with ElasticSearch
'tire' gem
https://github.com/karmi/retire


We then need to require following libraries


require 'rubygems'
require 'tire'

Indexing Records


Indexing includes both “Create” and “Update” in CRUD.
In order to make index request for new JSON object, we pass
the following URL

http://localhost:<port>/<index>/<type>/[<id>].

Indexing


Creating an index
curl -XPUT "http://localhost:9200/movies/movie/1" -d'
{

"title": "The Godfather",
"director": "Francis Ford Coppola",
"year": 1972




}'

Indexing Response

After executing the request, we get the following response
{







}
“ok”:
“_index”:
“_type”:
“_id”:
“_version”:
true,
“movies”,
“movie”,
“1”,
1

Retrieving Index

Retrieving the index

curl -XGET "http://localhost:9200/movies/movie/1" -d''

Retrieve Index Response
{







“_index”:
“_type”:
“_id”:
“_version”:
“exists”:
“_source”:





}
}
“movies”,
“movie”,
“1”,
1,
true,
{
"title": "The Godfather",
"director": "Francis Ford Coppola",
"year": 1972

Delete Index

Deleting the index

curl -XDELETE "http://localhost:9200/movies/movie/1" -d''

Demo Application

Demo Application by karmi

$ rails new searchapp -m
https://raw.github.com/karmi/tire/master/exam les/railsapplication-template.rb

Demo: Search App - Model

Model
include Tire::Model::Search
include Tire::Model::Callbacks




These two 'tire' models allow your rails application to use tire
gem for searching purposes

Demo: Search App
- Controller

Controller


@articles = Article.tire.search params[:query]
This line in your search method helps to search using tire gem

Demo: Search App - View

View




<%= form_tag search_articles_path, method: :get do %>
<%= text_field_tag :q, params[:query] %>
<%= submit_tag :search %>
<% end %>

Demo: Search App - Index

Create an index









Tire.index 'articles' do
delete
create
store :title => 'One', :tags => ['ruby']
store :title => 'Two', :tags => ['ruby', 'python']
store :title => 'Three', :tags => ['java']
store :title => 'Four', :tags => ['ruby', 'php']
refresh
end

Demo: Search App - Index

For custom mapping
Tire.index 'articles' do

delete
create :mappings => {
:article => {
:properties => {
:id
=> { :type => 'string', :index => 'not_analyzed', :include_in_all => false },
:title => { :type => 'string', :boost => 2.0, :analyzer => 'snowball' },
:tags => { :type => 'string', :analyzer => 'keyword' },
:content => { :type => 'string', :analyzer => 'snowball' }
}
}










}


end

Demo: Search App – Bulk
Indexing


For indexing large amount of data
articles = [






{ :id => '1', :type => 'article', :title => 'one', :tags => ['ruby'] },
{ :id => '2', :type => 'article', :title => 'two', :tags => ['ruby', 'python'] },
{ :id => '3', :type => 'article', :title => 'three', :tags => ['java'] },
{ :id => '4', :type => 'article', :title => 'four', :tags => ['ruby', 'php'] }
]
Use Import



Tire.index 'articles' do
import articles
end

Displaying Facets

For displaying facets
s.results.facets['global-tags']['terms'].each do |f|




puts "#{f['term'].ljust(10)} #{f['count']}"
end
Output




ruby
python
php
java
3
1
1
1

References
• https://github.com/karmi/retire
• http://railscasts.com/episodes/306-elasticsearch-part1
QUESTIONS?