o2app/bootstrap.py

   1 # Copyright (C) 2021 Wind River Systems, Inc.
   2 #
   3 #  Licensed under the Apache License, Version 2.0 (the "License");
   4 #  you may not use this file except in compliance with the License.
   5 #  You may obtain a copy of the License at
   6 #
   7 #      http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 #  Unless required by applicable law or agreed to in writing, software
  10 #  distributed under the License is distributed on an "AS IS" BASIS,
  11 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 #  See the License for the specific language governing permissions and
  13 #  limitations under the License.
  14
  15 from retry import retry
  16 import inspect
  17 from typing import Callable
  18
  19 from o2common.adapter.notifications import AbstractNotifications,\
  20     SmoO2Notifications
  21 from o2common.adapter import redis_eventpublisher
  22 from o2common.service import unit_of_work
  23
  24 from o2app.service import handlers, messagebus
  25 from o2app.adapter.unit_of_work import SqlAlchemyUnitOfWork
  26
  27 from o2ims.adapter import orm as o2ims_orm
  28 from o2dms.adapter import orm as o2dms_orm
  29
  30 from o2common.helper import o2logging
  31 logger = o2logging.get_logger(__name__)
  32
  33
  34 @retry(tries=100, delay=2, backoff=1)
  35 def wait_for_db_ready(engine):
  36     # wait for db up
  37     logger.info("Wait for DB ready ...")
  38     engine.connect()
  39     logger.info("DB is ready")
  40
  41
  42 def bootstrap(
  43     start_orm: bool = True,
  44     uow: unit_of_work.AbstractUnitOfWork = SqlAlchemyUnitOfWork(),
  45     notifications: AbstractNotifications = None,
  46     publish: Callable = redis_eventpublisher.publish,
  47 ) -> messagebus.MessageBus:
  48
  49     if notifications is None:
  50         notifications = SmoO2Notifications()
  51
  52     if start_orm:
  53         with uow:
  54             # get default engine if uow is by default
  55             engine = uow.session.get_bind()
  56             wait_for_db_ready(engine)
  57             o2ims_orm.start_o2ims_mappers(engine)
  58             o2dms_orm.start_o2dms_mappers(engine)
  59
  60     dependencies = {"uow": uow, "notifications": notifications,
  61                     "publish": publish}
  62     injected_event_handlers = {
  63         event_type: [
  64             inject_dependencies(handler, dependencies)
  65             for handler in event_handlers
  66         ]
  67         for event_type, event_handlers in handlers.EVENT_HANDLERS.items()
  68     }
  69     injected_command_handlers = {
  70         command_type: inject_dependencies(handler, dependencies)
  71         for command_type, handler in handlers.COMMAND_HANDLERS.items()
  72     }
  73
  74     return messagebus.MessageBus(
  75         uow=uow,
  76         event_handlers=injected_event_handlers,
  77         command_handlers=injected_command_handlers,
  78     )
  79
  80
  81 def inject_dependencies(handler, dependencies):
  82     params = inspect.signature(handler).parameters
  83     deps = {
  84         name: dependency
  85         for name, dependency in dependencies.items()
  86         if name in params
  87     }
  88     return lambda message: handler(message, **deps)