onddo/mysql_tuning-cookbook

# encoding: UTF-8
#
# Cookbook Name:: mysql_tuning
# Library:: mysql_helpers_cnf
# Author:: Xabier de Zuazo (<xabier@zuazo.org>)
# Copyright:: Copyright (c) 2014 Onddo Labs, SL.
# License:: Apache License, Version 2.0
#
# 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.
#

class MysqlTuningCookbook
  class MysqlHelpers
    # Some generic helpers related with configuration files
    class Cnf
      def self.version_satisfies?(version, requirement)
        return false if version.nil?
        gem_ver = Gem::Version.new(version)
        Gem::Requirement.new(requirement).satisfied_by?(gem_ver)
      end

      def self.fix_variable(name, old_names, version)
        return name unless old_names.key?(name)
        result = name
        old_names[name].each do |requirement, old_name|
          next unless version_satisfies?(version, requirement)
          Chef::Log.info("Fixing MySQL variable #{name} by #{old_name}")
          result = old_name
        end
        result
      end

      def self.round_variable(name, value, variables_block_size)
        if variables_block_size.key?(name)
          base = variables_block_size[name]
          (MysqlHelpers.mysql2num(value) / base).round * base
        else
          value
        end
      end

      def self.fix(cnf, block_sizes, old_names, version)
        cnf.each_with_object({}) do |(group, values), r|
          r[group] = {}
          values.each do |key, value|
            fixed_key = fix_variable(key, old_names, version)
            unless fixed_key.nil?
              fixed_value = round_variable(key, value, block_sizes)
              r[group][fixed_key] = fixed_value
            end
          end
        end
      end
    end
  end
end