Module: EmptyEye::ShardWrangler

Defined in:
lib/empty_eye/shard_wrangler.rb

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.create(master_class, t_name) ⇒ Object

this module method creates a ShardWrangler extended ActiveRecord inherited class the class will wrangle our shards



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# File 'lib/empty_eye/shard_wrangler.rb', line 13

def self.create(master_class, t_name)
  inherit_from = if master_class.base_class == master_class
    ActiveRecord::Base
  else
    master_class.superclass
  end
  
  table_name = if t_name
    t_name
  elsif master_class.descends_from_active_record?
    "#{master_class.name.underscore.pluralize}_core"
  else
    master_class.superclass.table_name
  end
  
  new_class = Class.new(inherit_from)
  new_class.send(:include, ShardWrangler)
  new_class.table_name = table_name
  new_class.master_class = master_class
  EmptyEye.const_set("#{master_class.to_s}Wrangler", new_class)
  new_class
end

.included(base) ⇒ Object

module which extends the class that serves as a pointer to the primary table when there is a superclass the shard will inherit from that, else it will inherit from ActiveRecord the primary shard manages all the MTI associated tables for the master class



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# File 'lib/empty_eye/shard_wrangler.rb', line 7

def self.included(base)
  base.extend ClassMethods
end

Instance Method Details

#cascade_save ⇒ Object

special save so that the wrangler can keep the master’s instance tables consistent



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# File 'lib/empty_eye/shard_wrangler.rb', line 50

def cascade_save
  write_attributes
  #this will autosave shards
  save
  #reset the id and then reload
  master_instance.id = id
  master_instance.reload
end

#master_class ⇒ Object

reflection on master class; this should never change



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# File 'lib/empty_eye/shard_wrangler.rb', line 60

def master_class
  self.class.master_class
end

#master_instance ⇒ Object

the instance that owns this wrangler we usually know the master instance ahead of time so we should take care to set this manually we want to avoid the lookup



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# File 'lib/empty_eye/shard_wrangler.rb', line 40

def master_instance
  @master_instance || master_class.find_by_id(id)
end

#master_instance=(instance) ⇒ Object

setter used to associate the wrangler with the master instance



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# File 'lib/empty_eye/shard_wrangler.rb', line 45

def master_instance=(instance)
  @master_instance = instance
end

#valid?(context = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/empty_eye/shard_wrangler.rb', line 64

def valid?(context = nil)
  context ||= (new_record? ? :create : :update)
  write_attributes
  output = super(context)
  errors.each do |attr, message|
    attr = attr.to_s.partition('.').last if attr.to_s =~ /\./
    master_instance.errors.add(attr, message)
  end
  errors.empty? && output
end