text: #
  # 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.
  """HBase storage backend migrations
  """
  
  import re
  
  from ceilometer.storage.hbase import utils as hbase_utils
  
  
  def migrate_resource_table(conn, table):
      """Migrate table 'resource' in HBase.
  
      Change qualifiers format from "%s+%s+%s!%s!%s" %
      (rts, source, counter_name, counter_type,counter_unit)
      in columns with meters f:m_*
      to new separator format "%s:%s:%s:%s:%s" %
      (rts, source, counter_name, counter_type,counter_unit)
      """
      resource_table = conn.table(table)
      resource_filter = ("QualifierFilter(=, "
                         "'regexstring:m_\\d{19}\\+"
                         "[\\w-\\._]*\\+[\\w-\\._!]')")
      gen = resource_table.scan(filter=resource_filter)
      for row, data in gen:
          columns = []
          updated_columns = dict()
          column_prefix = "f:"
          for column, value in data.items():
              if column.startswith('f:m_'):
                  columns.append(column)
                  parts = column[2:].split("+", 2)
                  parts.extend(parts.pop(2).split("!"))
                  column = hbase_utils.prepare_key(*parts)
                  updated_columns[column_prefix + column] = value
          resource_table.put(row, updated_columns)
          resource_table.delete(row, columns)
  
  
  def migrate_meter_table(conn, table):
      """Migrate table 'meter' in HBase.
  
      Change row format from "%s_%d_%s" % (counter_name, rts, message_signature)
      to new separator format "%s:%s:%s" % (counter_name, rts, message_signature)
      """
      meter_table = conn.table(table)
      meter_filter = ("RowFilter(=, "
                      "'regexstring:[\\w\\._-]*_\\d{19}_\\w*')")
      gen = meter_table.scan(filter=meter_filter)
      for row, data in gen:
          parts = row.rsplit('_', 2)
          new_row = hbase_utils.prepare_key(*parts)
          meter_table.put(new_row, data)
          meter_table.delete(row)
  
  
  def migrate_event_table(conn, table):
      """Migrate table 'event' in HBase.
  
      Change row format from ""%d_%s" % timestamp, event_id,
      to new separator format "%s:%s" % timestamp, event_id
      Also change trait columns from %s+%s % trait.name, trait.dtype
      to %s:%s % trait.name, trait.dtype
      """
      event_table = conn.table(table)
      event_filter = "RowFilter(=, 'regexstring:\\d*_\\w*')"
      gen = event_table.scan(filter=event_filter)
      trait_pattern = re.compile("f:[\w\-_]*\+\w")
      column_prefix = "f:"
      for row, data in gen:
          row_parts = row.split("_", 1)
          update_data = {}
          for column, value in data.items():
              if trait_pattern.match(column):
                  trait_parts = column[2:].rsplit('+', 1)
                  column = hbase_utils.prepare_key(*trait_parts)
              update_data[column_prefix + column] = value
          new_row = hbase_utils.prepare_key(*row_parts)
          event_table.put(new_row, update_data)
          event_table.delete(row)
  
  
  def migrate_alarm_history_table(conn, table):
      """Migrate table 'alarm_h' in HBase.
  
      Change row format from ""%s_%s" % alarm_id, rts,
      to new separator format "%s:%s" % alarm_id, rts
      """
      alarm_h_table = conn.table(table)
      alarm_h_filter = "RowFilter(=, 'regexstring:\\w*_\\d{19}')"
      gen = alarm_h_table.scan(filter=alarm_h_filter)
      for row, data in gen:
          row_parts = row.rsplit('_', 1)
          alarm_h_table.put(hbase_utils.prepare_key(*row_parts), data)
          alarm_h_table.delete(row)
  
  
  TABLE_MIGRATION_FUNCS = {'resource': migrate_resource_table,
                           'alarm_h': migrate_alarm_history_table,
                           'meter': migrate_meter_table,
                           'event': migrate_event_table}
  
  
  def migrate_tables(conn, tables):
      if type(tables) is not list:
          tables = [tables]
      for table in tables:
          if table in TABLE_MIGRATION_FUNCS:
              TABLE_MIGRATION_FUNCS.get(table)(conn, table)
  