lib/mongo/session/server_session.rb
# frozen_string_literal: true
# rubocop:todo all
# Copyright (C) 2017-2020 MongoDB Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
require 'mongo/session/server_session/dirtyable'
module Mongo
class Session
# An object representing the server-side session.
#
# @api private
#
# @since 2.5.0
class ServerSession
include Dirtyable
# Regex for removing dashes from the UUID string.
#
# @since 2.5.0
DASH_REGEX = /\-/.freeze
# Pack directive for the UUID.
#
# @since 2.5.0
UUID_PACK = 'H*'.freeze
# The last time the server session was used.
#
# @since 2.5.0
attr_reader :last_use
# The current transaction number.
#
# When a transaction is active, all operations in that transaction
# use the same transaction number. If the entire transaction is restarted
# (for example, by Session#with_transaction, in which case it would
# also invoke the block provided to it again), each transaction attempt
# has its own transaction number.
#
# Transaction number is also used outside of transactions for
# retryable writes. In this case, each write operation has its own
# transaction number, but retries of a write operation use the same
# transaction number as the first write (which is how the server
# knows that subsequent writes are retries and should be ignored if
# the first write succeeded on the server but was not read by the
# client, for example).
#
# @since 2.5.0
attr_reader :txn_num
# Initialize a ServerSession.
#
# @example
# ServerSession.new
#
# @since 2.5.0
def initialize
set_last_use!
session_id
@txn_num = 0
end
# Update the last_use attribute of the server session to now.
#
# @example Set the last use field to now.
# server_session.set_last_use!
#
# @return [ Time ] The last time the session was used.
#
# @since 2.5.0
def set_last_use!
@last_use = Time.now
end
# The session id of this server session.
#
# @example Get the session id.
# server_session.session_id
#
# @return [ BSON::Document ] The session id.
#
# @since 2.5.0
def session_id
@session_id ||= (bytes = [SecureRandom.uuid.gsub(DASH_REGEX, '')].pack(UUID_PACK)
BSON::Document.new(id: BSON::Binary.new(bytes, :uuid)))
end
# Increment the current transaction number and return the new value.
#
# @return [ Integer ] The updated transaction number.
#
# @since 2.5.0
def next_txn_num
@txn_num += 1
end
# Get a formatted string for use in inspection.
#
# @example Inspect the session object.
# session.inspect
#
# @return [ String ] The session inspection.
#
# @since 2.5.0
def inspect
"#<Mongo::Session::ServerSession:0x#{object_id} session_id=#{session_id} last_use=#{@last_use}>"
end
end
end
end