Class: Que::Connection

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/que/connection.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(connection) ⇒ Connection

Returns a new instance of Connection.



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# File 'lib/que/connection.rb', line 44

def initialize(connection)
  @wrapped_connection = connection
  @prepared_statements = Set.new
end

Instance Attribute Details

#wrapped_connection ⇒ Object (readonly)

Returns the value of attribute wrapped_connection.



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# File 'lib/que/connection.rb', line 23

def wrapped_connection
  @wrapped_connection
end

Class Method Details

.wrap(conn) ⇒ Object 



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# File 'lib/que/connection.rb', line 28

def wrap(conn)
  case conn
  when self
    conn
  when PG::Connection
    if conn.instance_variable_defined?(:@que_wrapper)
      conn.instance_variable_get(:@que_wrapper)
    else
      conn.instance_variable_set(:@que_wrapper, new(conn))
    end
  else
    raise Error, "Unsupported input for Connection.wrap: #{conn.class}"
  end
end

Instance Method Details

#drain_notifications ⇒ Object 



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# File 'lib/que/connection.rb', line 118

def drain_notifications
  loop { break if next_notification.nil? }
end

#execute(command, params = []) ⇒ Object 



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# File 'lib/que/connection.rb', line 49

def execute(command, params = [])
  sql =
    case command
    when Symbol then SQL[command]
    when String then command
    else raise Error, "Bad command! #{command.inspect}"
    end

  params = convert_params(params)

  result =
    Que.run_sql_middleware(sql, params) do
      # Some versions of the PG gem dislike an empty/nil params argument.
      if params.empty?
        wrapped_connection.async_exec(sql)
      else
        wrapped_connection.async_exec_params(sql, params)
      end
    end

  Que.internal_log :connection_execute, self do
    {
      backend_pid: backend_pid,
      command:     command,
      params:      params,
      ntuples:     result.ntuples,
    }
  end

  convert_result(result)
end

#execute_prepared(command, params = nil) ⇒ Object 



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# File 'lib/que/connection.rb', line 81

def execute_prepared(command, params = nil)
  Que.assert(Symbol, command)

  if !Que.use_prepared_statements || in_transaction?
    return execute(command, params)
  end

  name = "que_#{command}"

  begin
    unless @prepared_statements.include?(command)
      wrapped_connection.prepare(name, SQL[command])
      @prepared_statements.add(command)
      prepared_just_now = true
    end

    convert_result(
      wrapped_connection.exec_prepared(name, params)
    )
  rescue ::PG::InvalidSqlStatementName => error
    # Reconnections on ActiveRecord can cause the same connection
    # objects to refer to new backends, so recover as well as we can.

    unless prepared_just_now
      Que.log level: :warn, event: :reprepare_statement, command: command
      @prepared_statements.delete(command)
      retry
    end

    raise error
  end
end

#in_transaction? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/que/connection.rb', line 126

def in_transaction?
  wrapped_connection.transaction_status != ::PG::PQTRANS_IDLE
end

#next_notification ⇒ Object 



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# File 'lib/que/connection.rb', line 114

def next_notification
  wrapped_connection.notifies
end

#server_version ⇒ Object 



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# File 'lib/que/connection.rb', line 122

def server_version
  wrapped_connection.server_version
end