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     NoneNotifications
  21 from o2common.adapter import redis_eventpublisher
  22 from o2common.service import unit_of_work
  23 from o2common.service import messagebus
  24
  25 from o2app.service import handlers
  26 from o2app.adapter.unit_of_work import SqlAlchemyUnitOfWork
  27
  28 from o2ims.adapter import orm as o2ims_orm
  29 from o2dms.adapter import orm as o2dms_orm
  30
  31
  32 from o2common.helper import o2logging
  33 logger = o2logging.get_logger(__name__)
  34
  35
  36 @retry(tries=100, delay=2, backoff=1)
  37 def wait_for_db_ready(engine):
  38     # wait for db up
  39     logger.info("Wait for DB ready ...")
  40     engine.connect()
  41     logger.info("DB is ready")
  42
  43
  44 def bootstrap(
  45     start_orm: bool = True,
  46     uow: unit_of_work.AbstractUnitOfWork = SqlAlchemyUnitOfWork(),
  47     notifications: AbstractNotifications = None,
  48     publish: Callable = redis_eventpublisher.publish,
  49 ) -> messagebus.MessageBus:
  50
  51     if notifications is None:
  52         notifications = NoneNotifications()
  53
  54     if start_orm:
  55         with uow:
  56             # get default engine if uow is by default
  57             engine = uow.session.get_bind()
  58
  59             wait_for_db_ready(engine)
  60             o2ims_orm.start_o2ims_mappers(engine)
  61             o2dms_orm.start_o2dms_mappers(engine)
  62
  63     dependencies = {"uow": uow, "notifications": notifications,
  64                     "publish": publish}
  65     injected_event_handlers = {
  66         event_type: [
  67             inject_dependencies(handler, dependencies)
  68             for handler in event_handlers
  69         ]
  70         for event_type, event_handlers in handlers.EVENT_HANDLERS.items()
  71     }
  72     injected_command_handlers = {
  73         command_type: inject_dependencies(handler, dependencies)
  74         for command_type, handler in handlers.COMMAND_HANDLERS.items()
  75     }
  76
  77     bus = messagebus.MessageBus(
  78         uow=uow,
  79         event_handlers=injected_event_handlers,
  80         command_handlers=injected_command_handlers,
  81     )
  82     messagebus.MessageBus.set_instance(bus)
  83     return bus
  84
  85
  86 def inject_dependencies(handler, dependencies):
  87     params = inspect.signature(handler).parameters
  88     deps = {
  89         name: dependency
  90         for name, dependency in dependencies.items()
  91         if name in params
  92     }
  93     return lambda message: handler(message, **deps)