Class: TungstenScriptMySQLDatasource

Inherits:
TungstenScriptDatasource show all
Defined in:
lib/tungsten/datasources/mysql.rb

Instance Method Summary collapse

Methods inherited from TungstenScriptDatasource

#can_sql?, #initialize, #sql_result, #sql_results, #start, #stop

Constructor Details

This class inherits a constructor from TungstenScriptDatasource

Instance Method Details

#_start_server ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 53

def _start_server
  begin
    start_command = @ti.setting(TI.setting_key(REPL_SERVICES, @service, "repl_datasource_service_start"))
    TU.cmd_result("#{@ti.sudo_prefix()}#{start_command}")
  rescue CommandError
  end
  
  # Wait 30 seconds for the MySQL service to be responsive
  begin
    Timeout.timeout(30) {
      while true
        if is_running?()
          break
        else
          # Pause for a second before running again
          sleep 1
        end
      end
    }
  rescue Timeout::Error
    raise "The MySQL server has taken too long to start"
  end
end

#_stop_server ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 11

def _stop_server
  begin
    pid_file = get_variable("pid_file")
    pid = TU.cmd_result("#{@ti.sudo_prefix()}cat #{pid_file}")
  rescue CommandError
    pid = ""
  end
  
  begin
    stop_command = @ti.setting(TI.setting_key(REPL_SERVICES, @service, "repl_datasource_service_stop"))
    TU.cmd_result("#{@ti.sudo_prefix()}#{stop_command}")
  rescue CommandError
  end
  
  # Raise an error if we got a response to the previous command
  if is_running?() == true
    raise "Unable to properly shutdown the MySQL service"
  end
  
  # We saw issues where MySQL would not close completely. This will
  # watch the PID and make sure it does not appear
  unless pid.to_s() == ""
    begin
      TU.debug("Verify that the MySQL pid has gone away")
      Timeout.timeout(30) {
        pid_missing = false
        
        while pid_missing == false do
          begin
            TU.cmd_result("#{@ti.sudo_prefix()}ps -p #{pid}")
            sleep 5
          rescue CommandError
            pid_missing = true
          end
        end
      }
    rescue Timeout::Error
      raise "Unable to verify that MySQL has fully shutdown"
    end
  end
end

#can_lock_tables? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tungsten/datasources/mysql.rb', line 110

def can_lock_tables?
  true
end

#can_manage_service? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tungsten/datasources/mysql.rb', line 173

def can_manage_service?
  true
end

#get_mysql_command ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 177

def get_mysql_command
  host = @ti.setting(@ti.setting_key(REPL_SERVICES, @service, "repl_datasource_host"))
  port = @ti.setting(@ti.setting_key(REPL_SERVICES, @service, "repl_datasource_port"))
  my_cnf = @ti.setting(@ti.setting_key(REPL_SERVICES, @service, "repl_datasource_mysql_service_conf"))
  
  "mysql --defaults-file=#{my_cnf} -h#{host} --port=#{port}"
end

#get_option(opt) ⇒ Object

Read the configured value for a mysql variable



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# File 'lib/tungsten/datasources/mysql.rb', line 78

def get_option(opt)
  begin
    cnf = @ti.setting(@ti.setting_key(REPL_SERVICES, @service, "repl_datasource_mysql_service_conf"))
    val = TU.cmd_result("my_print_defaults --config-file=#{cnf} mysqld | grep -e'^--#{opt.gsub(/[\-\_]/, "[-_]")}='")
  rescue CommandError => ce
    return nil
  end

  return val.split("\n")[0].split("=")[1]
end

#get_system_user ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 99

def get_system_user
  if @mysql_user == nil
    @mysql_user = get_option("user")
    if @mysql_user.to_s() == ""
      @mysql_user = "mysql"
    end
  end
  
  @mysql_user
end

#get_variable(var) ⇒ Object

Read the current value for a mysql variable



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# File 'lib/tungsten/datasources/mysql.rb', line 90

def get_variable(var)
  begin
    sql_result("SHOW VARIABLES LIKE '#{var}'")[0]["Value"]
  rescue => e
    TU.debug(e)
    return nil
  end
end

#is_running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tungsten/datasources/mysql.rb', line 2

def is_running?
  begin
    sql_result("SELECT 1")
    return true
  rescue
    return false
  end
end

#lock_tables ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 114

def lock_tables
  if @lock_thread != nil
    TU.debug("Unable to lock tables because they are already locked")
    return
  end
  
  TU.debug("Run FLUSH TABLES WITH READ LOCK")
  @lock_thread = Thread.new(get_mysql_command()) {
    |mysql_command|
    status = Open4::popen4("export LANG=en_US; #{mysql_command}") do |pid, stdin, stdout, stderr|
      stdin.puts("SET wait_timeout=30;\n")
      stdin.puts("SET lock_wait_timeout=30;\n")
      stdin.puts("FLUSH TABLES WITH READ LOCK;\n")
      
      # Infinite loop to keep this thread alive until it is killed by the 
      # unlock_tables method
      while true
        sleep 60
      end
    end
  }
end

#snapshot_paths ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 148

def snapshot_paths
  paths = []
  
  # The datadir may not exist in my.cnf but we need the value
  # If we don't see it in my.cnf get the value from the dbms
  val = get_option("datadir")
  if val == nil
    val = get_variable("datadir")
  end
  paths << val
  
  # These values must appear in my.cnf if they are to be used
  val = get_option("innodb_data_home_dir")
  if val != nil
    paths << val
  end
  val = get_option("innodb_log_group_home_dir")
  if val != nil
    paths << val
  end
  
  # Only return a unique set of paths
  paths.uniq()
end

#unlock_tables ⇒ Object 



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# File 'lib/tungsten/datasources/mysql.rb', line 137

def unlock_tables
  if @lock_thread != nil
    begin
      Thread.kill(@lock_thread)
    rescue TypeError
    end

    @lock_thread = nil
  end
end