text: # Copyright (c) 2015,2019 Uber Technologies, Inc.
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  # THE SOFTWARE.
  
  from __future__ import absolute_import
  
  import logging
  
  from opentracing import tags
  
  
  from .. import utils
  from ._current_span import current_span_func
  from ._patcher import Patcher
  
  log = logging.getLogger(__name__)
  
  try:
      from sqlalchemy.engine import Engine
      from sqlalchemy import event
  except ImportError:
      pass
  
  
  class SQLAlchemyPatcher(Patcher):
      applicable = 'event' in globals()
  
      def _install_patches(self):
          log.info('Instrumenting SQLAlchemy for tracing')
          event.listen(Engine, 'before_cursor_execute',
                       self.before_cursor_execute)
          event.listen(Engine, 'after_cursor_execute',
                       self.after_cursor_execute)
  
      def _reset_patches(self):
          event.remove(Engine, 'before_cursor_execute',
                       self.before_cursor_execute)
          event.remove(Engine, 'after_cursor_execute',
                       self.after_cursor_execute)
  
      @staticmethod
      def before_cursor_execute(conn, cursor, statement, parameters, context,
                                executemany):
          operation = 'SQL'
          statement = statement.strip()
          if statement:
              operation = '%s %s' % (operation,
                                     statement.split(' ', 1)[0].upper())
          span = utils.start_child_span(
              operation_name=operation, parent=current_span_func())
          span.set_tag(tags.SPAN_KIND, tags.SPAN_KIND_RPC_CLIENT)
          span.set_tag(tags.COMPONENT, 'sqlalchemy')
          if conn.engine:
              span.set_tag(tags.DATABASE_TYPE, conn.engine.name)
              span.set_tag(tags.DATABASE_INSTANCE, repr(conn.engine.url))
          if statement:
              span.set_tag(tags.DATABASE_STATEMENT, statement)
          context.opentracing_span = span
  
      @staticmethod
      def after_cursor_execute(conn, cursor, statement, parameters, context,
                               executemany):
          if hasattr(context, 'opentracing_span') and context.opentracing_span:
              context.opentracing_span.finish()
              context.opentracing_span = None
  
  
  SQLAlchemyPatcher.configure_hook_module(globals())
  