Class: MultipleConnectionHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/multiple_connection_handler.rb

Overview

grants access to db connections for several environments at once. implemented as a singleton accessed through class methods.

Defined Under Namespace

Classes: DbKey, DoubleInitializationError, UnrecognizedDatabaseError

Constant Summary collapse

@@static_initialized = 
false

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#configurations ⇒ Object

Returns the value of attribute configurations.



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# File 'lib/multiple_connection_handler.rb', line 79

def configurations
  @configurations
end

#db_config_file ⇒ Object

Returns the value of attribute db_config_file.



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# File 'lib/multiple_connection_handler.rb', line 79

def db_config_file
  @db_config_file
end

#established_connections ⇒ Object

Returns the value of attribute established_connections.



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# File 'lib/multiple_connection_handler.rb', line 80

def established_connections
  @established_connections
end

#handler ⇒ Object

Returns the value of attribute handler.



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# File 'lib/multiple_connection_handler.rb', line 79

def handler
  @handler
end

Class Method Details

.connection(spec_name) ⇒ Object

return a db connection for the specified name, establishing new pools with the AR connection handler if necessary



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# File 'lib/multiple_connection_handler.rb', line 44

def self.connection(spec_name)
  instance.connection(spec_name)
end

.db_name(spec_name) ⇒ Object

returns the db name for the given spec name



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# File 'lib/multiple_connection_handler.rb', line 50

def self.db_name(spec_name)
  instance.configurations[spec_name.to_s]['database']
end

.init(options = {}) ⇒ Object

initialize the connections handler. only necessary to be called if overriding any default configuration. recommend against using this method explicitly and just allowing default.

options:

- :config_file => the database config file to use. default is the
                  rails default of ..../config/database.yml



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# File 'lib/multiple_connection_handler.rb', line 63

def self.init(options = {})
  # don't allow re-initializing. just ignore if we're already initialized
  # unless we're asked to use a different config file
  if @@static_initialized
    if @@instantiated && options[:config_file] &&
        options[:config_file] != instance.db_config_file

      raise DoubleInitializationError
    end
  else
    @@db_config_file = options[:config_file] || "#{RAILS_ROOT}/config/database.yml"
    @@static_initialized = true
  end

end

Instance Method Details

#connection(spec_name) ⇒ Object

the meat of the work is done here. retrieve a connection using cached connections or get a new one.



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# File 'lib/multiple_connection_handler.rb', line 88

def connection(spec_name)
  db_key = DbKey.new(spec_name.to_s)

  unless established_connections.member? db_key
    unless configurations.include? db_key.name
      raise UnrecognizedDatabaseError.new(db_key.name, db_config_file)
    end

    spec = configurations[db_key.name]

    handler.establish_connection(db_key.name,
      ActiveRecord::Base::ConnectionSpecification.new(spec,
        "#{spec['adapter']}_connection"))

    established_connections.add db_key.name
  end # end connection not established yet

  handler.retrieve_connection db_key
end