Module: Wukong::Store::CassandraModel

Defined in:
lib/wukong/store/cassandra_model.rb,
lib/wukong/store/cassandra/streaming.rb

Overview

Barebones interface between a wukong class and a cassandra database

Class must somehow provide a class-level cassandra_db accessor that sets the @cassandra_db instance variable.

Defined Under Namespace

Modules: ClassMethods Classes: AvroWriter

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

The standard ‘inject class methods when module is included’ trick



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# File 'lib/wukong/store/cassandra_model.rb', line 67

def self.included base
  base.class_eval{ extend ClassMethods}
end

Instance Method Details

#save ⇒ Object

Store model to the DB



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# File 'lib/wukong/store/cassandra_model.rb', line 13

def save
  self.class.insert key, self.to_db_hash
end

#streaming_save ⇒ Object

Store model using avro writer



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# File 'lib/wukong/store/cassandra/streaming.rb', line 9

def streaming_save
  self.class.streaming_insert id, self
end

#to_db_hash ⇒ Object

Flatten attributes for storage in the DB.

  • omits elements whose value is nil

  • calls to_s on everything else

  • This means that blank strings are preserved;

  • and that false is saved as ‘false’

Override if you think something fancier than that should happen.



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# File 'lib/wukong/store/cassandra_model.rb', line 27

def to_db_hash
  db_hsh = {}
  each_pair{|k,v| db_hsh[k.to_s] = v.to_s unless v.nil? }
  db_hsh
end