Class: Moneta::Adapters::Cassandra

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

Overview

Cassandra backend

Instance Attribute Summary collapse

Attributes included from ExpiresSupport

#default_expires

Instance Method Summary collapse

Methods included from Defaults

#[], #[]=, #close, #create, #decrement, #features, #fetch, included, #increment, #supports?

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

  • :backend (::Cassandra) —

    Use existing backend instance



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# File 'lib/moneta/adapters/cassandra.rb', line 23

def initialize(options = {})
  self.default_expires = options[:expires]
  @cf = (options[:column_family] || 'moneta').to_sym
  if options[:backend]
    @backend = options[:backend]
  else
    keyspace = options[:keyspace] || 'moneta'
    @backend = ::Cassandra.new('system', "#{options[:host] || '127.0.0.1'}:#{options[:port] || 9160}")
    unless @backend.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
          @backend.add_keyspace(ks_def)
        rescue Exception => ex
          warn "Moneta::Adapters::Cassandra - #{ex.message}"
        end
        break if @backend.keyspaces.include?(keyspace)
        sleep 0.1
      end
    end
    @backend.keyspace = keyspace
  end
end

Instance Attribute Details

#backend ⇒ Object (readonly) 



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# File 'lib/moneta/adapters/cassandra.rb', line 14

def backend
  @backend
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 91

def clear(options = {})
  @backend.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: {})

Options Hash (options):

  • :raw (Boolean) —

    Raw access without value transformation (See Transformer)

  • :prefix (String) —

    Prefix key (See Transformer)

  • Other (Object) —

    options as defined by the adapters or middleware

Returns:

  • (Object) —

    current value



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# File 'lib/moneta/adapters/cassandra.rb', line 83

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

#key?(key, options = {}) ⇒ Boolean

Exists the value with key

Parameters:

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

Options Hash (options):

  • :expires (Integer) —

    Update expiration time (See Expires)

  • :prefix (String) —

    Prefix key (See Transformer)

  • Other (Object) —

    options as defined by the adapters or middleware

Returns:

  • (Boolean) 


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# File 'lib/moneta/adapters/cassandra.rb', line 54

def key?(key, options = {})
  if @backend.exists?(@cf, key)
    load(key, options) if options.include?(:expires)
    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: {})

Options Hash (options):

  • :expires (Integer) —

    Update expiration time (See Expires)

  • :raw (Boolean) —

    Raw access without value transformation (See Transformer)

  • :prefix (String) —

    Prefix key (See Transformer)

  • Other (Object) —

    options as defined by the adapters or middleware

Returns:

  • (Object) —

    value



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# File 'lib/moneta/adapters/cassandra.rb', line 64

def load(key, options = {})
  if value = @backend.get(@cf, key)
    expires = expires_value(options, nil)
    @backend.insert(@cf, key, {'value' => value['value'] }, :ttl => expires || nil) if expires != nil
    value['value']
  end
end

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

Store value with key

Parameters:

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

Options Hash (options):

  • :expires (Integer) —

    Set expiration time (See Expires)

  • :raw (Boolean) —

    Raw access without value transformation (See Transformer)

  • :prefix (String) —

    Prefix key (See Transformer)

  • Other (Object) —

    options as defined by the adapters or middleware

Returns:

  • value



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# File 'lib/moneta/adapters/cassandra.rb', line 73

def store(key, value, options = {})
  @backend.insert(@cf, key, {'value' => value}, :ttl => expires_value(options) || nil)
  value
rescue
  # FIXME: We get spurious cassandra transport exceptions
  tries ||= 0
  (tries += 1) < 10 ? retry : raise
end