file.rb

class StreamMysql

 def initialize
     read_config_file
 end

def mysql_connection
        puts "mysql_connection"
        @connexion = Mysql2::Client.new(:host => @conf['host'], :username => @conf['user'], :password => @conf['password'], :database=> @conf['base'], :port => @conf['port'])
#         @connexion.query if @connexion
#        if @connexion
#    
#        end 
 end 

 def mysql_select(value = "*")
        puts "select"
         if mysql_connection then
            mysql_connection.query("select #{value} from User") 
          else
        end 
 end 

 def read_config_file
        config = YAML::load_file(File.join(__dir__, 'config.yml'))
        @conf   = config['database']
 end 
end

StreamMysql.new