Class: Moneta::Adapters::Cassandra

Inherits:
Object
  • Object
show all
Includes:
Defaults
Defined in:
lib/moneta/adapters/cassandra.rb

Overview

Cassandra backend

Instance Method Summary collapse

Methods included from Defaults

#[], #[]=, #close, #decrement, #fetch, #increment

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(options = {}) ⇒ Cassandra

Returns a new instance of Cassandra.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :keyspace (String) — default: 'moneta' —

    Cassandra keyspace

  • :column_family (String) — default: 'moneta' —

    Cassandra column family

  • :host (String) — default: '127.0.0.1' —

    Server host name

  • :port (Integer) — default: 9160 —

    Server port

  • :expires (Integer) —

    Default expiration time



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# File 'lib/moneta/adapters/cassandra.rb', line 19

def initialize(options = {})
  options[:host] ||= '127.0.0.1'
  options[:port] ||=  9160
  @expires = options[:expires]
  keyspace = (options[:keyspace] ||= 'moneta')
  @cf = (options[:column_family] || 'moneta').to_sym
  @client = ::Cassandra.new('system', "#{options[:host]}:#{options[:port]}")
  unless @client.keyspaces.include?(keyspace)
    cf_def = ::Cassandra::ColumnFamily.new(:keyspace => keyspace, :name => @cf.to_s)
    ks_def = ::Cassandra::Keyspace.new(:name => keyspace,
                                       :strategy_class => 'SimpleStrategy',
                                       :strategy_options => { 'replication_factor' => '1' },
                                       :replication_factor => 1,
                                       :cf_defs => [cf_def])
    # Wait for keyspace to be created (issue #24)
    10.times do
      begin
        @client.add_keyspace(ks_def)
      rescue Exception => ex
        puts "Cassandra: #{ex.message}"
      end
      break if @client.keyspaces.include?(keyspace)
      sleep 0.1
    end
  end
  @client.keyspace = keyspace
end

Instance Method Details

#clear(options = {}) ⇒ void

This method returns an undefined value.

Clear all keys in this store

Parameters:

  • options (Hash) (defaults to: {}) 


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# File 'lib/moneta/adapters/cassandra.rb', line 86

def clear(options = {})
  @client.each_key(@cf) do |key|
    delete(key)
  end
  self
end

#delete(key, options = {}) ⇒ Object

Delete the key from the store and return the current value

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Returns:

  • (Object) —

    current value



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# File 'lib/moneta/adapters/cassandra.rb', line 78

def delete(key, options = {})
  if value = load(key, options)
    @client.remove(@cf, key)
    value
  end
end

#key?(key, options = {}) ⇒ Boolean

Exists the value with key

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Returns:

  • (Boolean) 


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# File 'lib/moneta/adapters/cassandra.rb', line 48

def key?(key, options = {})
  if @client.exists?(@cf, key)
    if options.include?(:expires) && (value = load(key))
      store(key, value, options)
    end
    true
  else
    false
  end
end

#load(key, options = {}) ⇒ Object

Fetch value with key. Return nil if the key doesn’t exist

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Returns:

  • (Object) —

    value



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# File 'lib/moneta/adapters/cassandra.rb', line 60

def load(key, options = {})
  value = @client.get(@cf, key)
  if value
    if options.include?(:expires)
      store(key, value['value'], options)
    else
      value['value']
    end
  end
end

#store(key, value, options = {}) ⇒ Object

Store value with key

Parameters:

  • key (Object)
  • value (Object)
  • options (Hash) (defaults to: {})

Returns:

  • value



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# File 'lib/moneta/adapters/cassandra.rb', line 72

def store(key, value, options = {})
  @client.insert(@cf, key, {'value' => value}, :ttl => (options[:expires] || @expires))
  value
end