Tanker - IndexTank integration to your favorite orm¶ ↑

IndexTank is a great search indexing service, this gem tries to make that any orm stays in sync with IndexTank easily. It has a simple yet powerful approach to integrate IndexTank with any ORM and also supports pagination using WillPaginate (default) or Kaminari.

Very little is needed to make it work, basically, all you need is that the orm instance respond to id, all, find and any attributes you wish to index.

Installation¶ ↑

gem install tanker

If you are using Rails 3 its better to add Tanker to your GEMFILE

gem 'tanker'

And run

bundle install

Initialization¶ ↑

If you’re using Rails, config/initializers/tanker.rb is a good place for this:

YourAppName::Application.config.index_tank_url = 'http://:xxxxxxxxx@xxxxx.api.indextank.com'

If you are not using rails you can put this somewhere before you load your models

Tanker.configuration = {:url => 'http://:xxxxxxxxx@xxxxx.api.indextank.com' }

You would probably want to have fancier configuration depending on your environment. Be sure to copy and paste the correct url provided by the IndexTank Dashboard

Pagination¶ ↑

WillPaginate is used by default and you don’t have to add any extra settings to use that. If you want to use Kaminari you have to add the following:

YourAppName::Application.config.index_tank_url = 'http://...'
YourAppName::Application.config.tanker_pagination_backend = :kaminari

Tanker.configuration = {:url => 'http://...', :pagination_backend => :kaminari }

Example¶ ↑

class Topic < ActiveRecord::Base
  acts_as_taggable
  has_many :authors

  # just include the Tanker module
  include Tanker

  # define a scope
  scope :awesome, :conditions => {:title => 'Awesome'}

  # define the index by supplying the index name and the fields to index
  # this is the index name you create in the Index Tank dashboard
  # you can use the same index for various models Tanker can handle
  # indexing searching on different models with a single Index Tank index
  tankit 'my_index' do

    conditions do
      indexable?
    end

    indexes :title
    indexes :content
    indexes :id
    indexes :tag_list #NOTICE this is an array of Tags! Awesome!
    indexes :category, :category => true # make attributes also be categories (facets)

    # you may also dynamically retrieve field data
    indexes :author_names do
      authors.map {|author| author.name }
    end

    # you cal also dynamically set categories
    category :content_length do
      content.length
    end

    # to pass in a list of variables with your document,
    # supply a hash with the variable integers as keys:
    variables do
      {
        0 => authors.first.id, # these will be available in your queries
        1 => id                # as doc.var[0] and doc.var[1]
      }
    end

    # You may defined some server-side functions that can be
    # referenced in your queries. They're always referenced by
    # their integer key:
    functions do
      {
        1 => '-age',
        2 => 'doc.var[0] - doc.var[1]'
      }
    end
  end

  # define the callbacks to update or delete the index
  # these methods can be called whenever or wherever
  # this varies between ORMs
  after_save :update_tank_indexes
  after_destroy :delete_tank_indexes

  # Note! Will Paginate pagination, thanks mislav!
  def self.per_page
    5
  end

  # will only index entries whose title is present
  def indexable?
    self.title.present?
  end

end

Create Topics

Topic.create(:title => 'Awesome Topic', :content => 'blah, blah', :tag_list => 'tag1, tag2')
Topic.create(:title => 'Bad Topic', :content => 'blah, blah', :tag_list => 'tag1')
Topic.create(:title => 'Cool Topic', :content => 'blah, blah', :tag_list => 'tag3, tag2')

Search Topics

@topics = Topic.search_tank('Topic', :page => 1, :per_page => 10) # Gets 3 results!
@topics = Topic.search_tank('blah',  :conditions => {:tag_list => 'tag1'}) # Gets 2 results!
@topics = Topic.search_tank('blah',  :conditions => {:title => 'Awesome', :tag_list => 'tag1'}) # Gets 1 result!

Search with scope (Only tested on ActiveRecord)

@topics = Topic.awesome.search_tank('blah') # Gets 1 result!

Search with wildcards!

@topics = Topic.search_tank('Awe*', :page => 1, :per_page => 10) # Gets 1 result!

Search multiple models

@results = Tanker.search([Topic, Post], 'blah') # Gets any Topic OR Post results that match!

Search with negative conditions

@topics = Topic.search_tank('keyword',  :conditions => {'tag_list' => 'tag1'}) # Gets 1 result!
@topics = Topic.search_tank('keyword',  :conditions => {'-id' => [5,9]}) # Ignores documents with ids of '5' or '9'

Search with query variables

@topics = Topic.search_tank('keyword',  :variables => {0 => 5.6}) # Makes 5.6 available server-side as q[0]

Paginate Results

<%= will_paginate @topics %> for WillPaginate
<%= paginate @topics %> for Kaminari

Fetching attributes and snippets¶ ↑

As of version 1.1 Tanker supports fetching attributes and snippets directly from the Index. If you use either of these search options your Model instances will be instanced from the attributes coming from the index not by making another trip to the database.

This can represent a major speed increase for your queries but it also means that you will only have available the attributes you indexed in your model. There are edge cases that are not tested so please help us have this feature be super stable and have everyone benefit from the speed this entails.

Example:

@very_long_sting = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.'
Product.create(:name => @very_long_sting, :href => 'http://google.com' )

@products = Product.search_tank('quis exercitation', :snippets => [:name], :fetch => [:href])
@products[0].name_snippet
# => 'Ut enim ad minim veniam, <b>quis</b> nostrud <b>exercitation</b> ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla'
@products[0].href
# => 'http://google.com'
@products[0].any_other_attribute
# => nil

Notice that to get the snippeted value that Index Tank sends you get it via the ‘_snippet’ method generated on the fly.

The attributes that are requested to be fetched are set as attributes as new instances of your model objects and no Database Query is executed. NEAT!

Geospatial Search Example¶ ↑

IndexTank and the Tanker gem support native geographic calculations. All you need is to define two document variables with your latitude and your longitude

class Restaurant < ActiveRecord::Base
  include Tanker

  tankit 'my_index' do
    indexes :name

    # You may define lat/lng at any variable number you like, as long
    # as you refer to them consistently with the same integers
    variables do
      {
        0 => lat
        1 => lng
      }
    end

    functions do
      {
        # This function is good for sorting your results. It will
        # rank relevant, close results higher and irrelevant, distant results lower
        1 => "relevance / miles(d[0], d[1], q[0], q[1])",

        # This function is useful for limiting the results that your query returns.
        # It just calculates the distance of each document in miles, which you can use
        # in your query. Notice that we're using 0 and 1 consistently as 'lat' and 'lng'
        2 => "miles(d[0], d[1], q[0], q[1])"
      }
    end
  end
end

# When searching, you need to provide a latitude and longitude in the query so that
# these variables are accessible on the server.
Restaurant.search("tasty",
                  :var0 => 47.689948,
                  :var1 => -122.363684,
                  # And we'll return all results sorted by distance
                  :function => 1)

# Or we can use just function 2 to return results in the default order, while
# limiting the total results to just those within 50 miles from our lat/lng:
Restaurant.search("tasty",
                  :var0 => 47.689948,
                  :var1 => -122.363684,
                  # the following is a fancy way of saying "return all results where
                  the result of function 2 is at least anything and less than 50"
                  :filter_functions => {2 => [['*', 50]]})
# And we can combine these two function calls to return only results within 50 miles
# and sort them by relevance / distance:
Restaurant.search("tasty",
                  :var0 => 47.689948,
                  :var1 => -122.363684,
                  :function => 1,
                  :filter_functions => {2 => [['*', 50]]})

Extend your index definitions¶ ↑

If you have a bunch of models with a lot of overlapping indexed fields, variables, or categories, you might want to abstract those out into a module that you can include and then extend in the including classes. Something like:

module TankerDefaults
  def self.included(base)
    base.send(:include, ::Tanker) # include the actual Tanker module

    # provide a default index name
    base.tankit 'my_index' do
      # index some common fields
      indexes :tag_list

      # set some common variables
      variables do
        {
          0 => view_count
          1 => foo
        }
      end
    end
  end
end

class SuperModel
  include TankerDefaults

  # no need to respecify the index if it's the same
  # (but you can override it)
  tankit do
    # `indexes :tag_list` is inherited
    indexes :name
    indexes :boyfriend_names do
      boyfriends.map(&:name)
    end

    # set some more specific variables
    variables do
      {
        # `0 => view_count` is inherited
        1 => iq,                 # overwrites "foo"
        2 => endorsements.count  # adds new variables
      }
    end
  end
end

You currently can’t remove previously defined stuff, though.

Single table inheritance¶ ↑

If you are using tanker with STI models and want the different models to be indexed as the same type, you can provide the base model name with an :as option to tankit.

module TankerPetDefaults
  def self.included(base)
    base.send(:include, ::Tanker)

    base.tankit 'my_index', :as => 'Pet' do
      indexes :skills
    end
  end
end

class Pet < ActiveRecord::Base
end

class Cat < Pet
  include TankerPetDefaults
end

class Monkey < Pet
  include TankerPetDefaults
end

# Search using the base model
Pet.search('stealth')

Reindex your data¶ ↑

If you are using rails 3 there are of couple of rake tasks included in your project

rake tanker:clear_indexes

This task deletes all your indexes and recreates empty indexes, if you have not created the indexes in the Index Tank interface this task creates them for you provided you have enough available indexes in your account.

rake tanker:reindex

This task pushes any functions you’ve defined in your tankit() blocks to indextank.com

rake tanker:functions

This task re-indexes all the your models that have the Tanker module included. Usually you will only need a single Index Tank index but if you want to separate your indexes please use different index names in the tankit method call in your models

To reindex just one class rather than all the classes in your application just call:

Model.tanker_reindex

And if you’d like to specify a custom number of records to PUT with each call to indextank.com you may specify it as the first argument:

Model.tanker_reindex(:batch_size => 1000) # defaults to batch size of 200

Or you can restrict indexing to a subset of records. This is particularly helpful for massive datasets where only a small portion of the records is useful.

Model.tanker_reindex(:batch_size => 1000, :scope => :not_deleted) # will call Model.not_deleted.all internally

Note on Patches/Pull Requests¶ ↑

Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don’t break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.

Note on testing¶ ↑

Tanker is has a full suite of unit tests that cover configuration and the api of the library but it also inludes a battery of Integration tests! These tests spec the behabiero between Index Tank and an ActiveRecord model with a Sqlite3 Backend.

If you want to run the specs you will need to provide an Index Tank Api key and user in the spec/integration_spec_conf.rb file. This file is ignored from the repo but you’ll find an example file in the same path.

Acknowledgements¶ ↑

The gem is based on a couple of projects:

Kudos to this awesome projects and developers

There is a growing list of colabrators to this Gem so I would briefly mention them so if you know them and use this gem buy them a beer!

samuelhwong/tanker