Class: LanGrove::Plugin::Persistor

Inherits:
DataSource show all
Defined in:
lib/langrove/plugin/persistor.rb

Direct Known Subclasses

BufferedPersistor, YamlFile

Instance Attribute Summary

Attributes inherited from Base

#logger

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#config_exception, #type

Constructor Details

#initialize(root, config, name = nil) ⇒ Persistor

Returns a new instance of Persistor.



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# File 'lib/langrove/plugin/persistor.rb', line 101

def initialize( root, config, name = nil ) 
   
  super( root, config, name )
  
  @allow_learn = @config[:allow_learn]
  #
  # If enabled, this config key enables allowing
  # a fetch() that failed to return anything to
  # process as if there was nothing to fetch,
  # 
  # ie. 
  #    It is new, not yet persisted.
  #
  # 
  
  validate_config
  
  @provides = {
    
    :persistor => {
      
      :version => PERSISTOR_VERSION
      
    }
    
  }

end

Class Method Details

.type ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 20

def self.type
  
  :persistor
  
end

Instance Method Details

#all_capsules(&block) ⇒ Object

Raises:



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# File 'lib/langrove/plugin/persistor.rb', line 26

def all_capsules( &block )
  
  #
  # OVERRIDE
  # 
  # Should collect from storage
  # ALL the persisted casules,
  # 
  # each a Hash
  #
  # and yield the key and the capsule
  # 
  # OR raise exception
  #
   
  raise LanGrove::PluginException.new(

    "#{self.class}.all_capsules() not implemented."
    
  )
  
end

#fetch(handler) ⇒ Object

Raises:



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# File 'lib/langrove/plugin/persistor.rb', line 70

def fetch( handler )

  #
  # OVERRIDE
  # 
  # To populate the capsule from Persistance
  # 
  # Return true or THROW EXCEPTION.
  # 
  
  raise LanGrove::PluginException.new(

    "#{self.class}.fetch() not implemented."
  
  )
  
end

#fetch_all(multiplexer = nil, &block) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 243

def fetch_all( multiplexer = nil, &block )
  
  config_exception(

    "#{self.class}.fetch_all() only acts on multiplexer"

  ) if ( 
  
    block.nil? and 
    not multiplexer.respond_to?( :create_handler )
  
  )

  count = 0

  all_capsules do |key, capsule|
    
    count += 1
  
    handler = multiplexer.create_handler( 
  
      key, capsule, capsule
  
    ) unless multiplexer.nil?
    
    yield capsule if block
  
  end
  
  @logger.warn "#{self.class} preloaded #{count} handlers" 

end

#fetch_all_handler(multiplexer) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 277

def fetch_all_handler( multiplexer )
  
  fetch_all( multiplexer )
  
end

#fetch_handler(handler) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 152

def fetch_handler( handler )
  
  @root.trigger( handler, :handler, :fetch )
  
  #
  # Plugin implementable fetch
  #
  if fetch( handler )
  
    @root.trigger( handler, :handler, :after_fetch )
    
  end
 
end

#gen_key(handler) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 168

def gen_key( handler )
  
  #
  # Use the pending capsule to assemble the
  # persistance key.
  #
  data_hash = handler.pending_capsule if handler.respond_to?( :pending_capsule )
  
  #
  # Fall back to using the actual capsule
  #
  if data_hash.nil?
    
    data_hash = handler.capsule
    
  end

  data_hash = transform( data_hash, :store )

  storage_address = {
    
    'table' => @table,
    'key' => {}
  
  }

  @key.each do |key_name, key_map|
    
    storage_address['key'][key_name] = data_hash[key_map]

    unless handler.capsule.nil?
      
      #
      # For mongo, put _id into capsule
      # 
      handler.capsule[key_name] = data_hash[key_map]
    
    end
    
    if storage_address['key'][key_name].nil?
      
      @logger.error "Missing key data in #{data_hash.inspect}"
      
      #
      # This exception brings the whole server down
      # 
      # Which is good
      # 
      # But when it fires inside a deferred proc it
      # only takes out the proc...
      # 
      # Then when a callback fires the proc is gone
      # and EventMachine::ConnectionNotBound 
      # exception is raised
      # 
      # It still takes down the Daemon, but the original 
      # exception is lost.
      # 
      
      behaviour_exception( 
      
        'Missing key data.'
      
      )
      
    end
    
  end
  
  handler.key = storage_address
  
  return true
  
end

#next_seq ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 339

def next_seq
  
  #
  # Unlikely to reach MAX_INT before a daemon 
  # is restarted for what ever reason,
  # 
  # But just incase
  # 
  
  @seq = 0 if @seq.nil?
  
  @seq = 0 if @seq == MAX_INT
  
  @seq += 1
  
end

#store(handler) ⇒ Object

Raises:



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# File 'lib/langrove/plugin/persistor.rb', line 49

def store( handler )
  
  #
  # OVERRIDE
  # 
  # To 'save' the capsule.
  # 
  # Persist the handler.capsule
  # 
  # Return true or false.
  # 

  raise LanGrove::PluginException.new(

    "#{self.class}.store() not implemented."
    
  )

end

#store_handler(handler) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 131

def store_handler( handler )
  
  @root.trigger( handler, :handler, :store )
  
  #
  # Insert sequence number into capsule
  #
  handler.capsule['persisted_seq'] = next_seq
  
  #
  # Plugin implementable store
  #
  if store( handler )
  
    @root.trigger( handler, :handler, :after_store )
  
  end
  
end

#transform(capsule, action = nil) ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 88

def transform( capsule, action = nil )

  #
  # OVERRIDE 
  # 
  # To perform any necessary transforms
  # on the capsule just ahead of storage
  #

  return capsule

end

#validate_config ⇒ Object 



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# File 'lib/langrove/plugin/persistor.rb', line 284

def validate_config
  
  #
  # Defaults:
  #
  # DatabaseName as configured :system: name
  # TableName as configured :applicaiton: name
  #
  @database = @root.config.system
  @table = @root.config.application
  
  @logger.warn( 
  
    "#{self.class} defaulting :database: to '#{@database}'"
    
  ) if ( 
  
    @config[ :database ].nil? or
    not @database = @config[ :database ]
    
  )
  
  @logger.warn( 
  
    "#{self.class} defaulting :table: to '#{@table}'"
    
  ) if ( 
  
    @config[ :table ].nil? or
    not @table = @config[ :table ]
    
  )
  
  config_exception(
  
    "#{self.class} requires :key:"
  
  ) unless @key = @config[:key]
  
  config_exception(
  
    "#{self.class} requires at least one :key_name: defined in :key:"
  
  ) unless @key.size > 0
  
  config_exception(
  
    "#{self.class} requires a value for :key:#{@key.first[0]}:"
  
  ) if @key.first[1] == nil or @key.first[1] == ''

  @key = transform( @key, :key )
  
end