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# ============LICENSE_START=======================================================
# Copyright (c) 2021 AT&T Intellectual Property. All rights reserved.
# ================================================================================
# 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.
# ============LICENSE_END=========================================================
"""
Asyncio coroutine setup for both periodic and real time notification tasks """
import signal
import asyncio
from prometheus_client import start_http_server
from .inventory import Inventory
from .util import get_module_logger
SLEEP_ON_ERROR = 10
logger = get_module_logger(__name__)
async def notify_task(inventory, sleep):
"""
start the notification task
:param inventory: Inventory
:param sleep: how long to wait on error in seconds
"""
logger.info("opening notificationhandler for policy...")
await inventory.client.notificationhandler(
inventory.check_and_update,
ids=inventory.policy_ids,
filters=inventory.policy_filters,
)
logger.warning("websocket closed or errored...will attempt reconnection")
await asyncio.sleep(sleep)
async def periodic_task(inventory, sleep):
"""
start the periodic task
:param inventory: Inventory
:param sleep: how long to wait between periodic checks
"""
await asyncio.sleep(sleep)
logger.info("Executing periodic check of PDP policies")
await inventory.update()
async def task_runner(inventory, sleep, task, should_run):
"""
Runs a task in an event loop
:param inventory: Inventory
:param sleep: how long to wait between loop iterations
:param task: coroutine to run
:param should_run: function for should this task continue to run
"""
# pylint: disable=broad-except
while should_run():
try:
await task(inventory, sleep)
except asyncio.CancelledError:
break
except Exception:
logger.exception("Received exception")
async def shutdown(loop, tasks, inventory):
"""
shutdown the event loop and cancel all tasks
:param loop: Asyncio eventloop
:param tasks: list of asyncio tasks
:param inventory: the inventory object
"""
logger.info("caught signal")
# Stop the websocket routines
for task in tasks:
task.cancel()
await task
# Close the client
await inventory.close()
loop.stop()
def _setup_coroutines(
loop,
inventory,
shutdown_handler,
task_r,
**kwargs
):
""" sets up the application coroutines"""
# Task runner takes a function for stop condition
# (for testing purposes) but should always run in practice
# pylint: disable=broad-except
def infinite_condition():
return True
logger.info("Starting gather of all policies...")
try:
loop.run_until_complete(inventory.gather())
except Exception:
logger.exception('received exception on initial gather')
# websocket and the periodic check of policies
tasks = [
loop.create_task(
task_r(
inventory,
kwargs.get('check_period', 2400),
periodic_task,
infinite_condition
)
)
]
if inventory.client.supports_notifications():
tasks.append(
loop.create_task(
task_r(
inventory,
SLEEP_ON_ERROR,
notify_task,
infinite_condition
)
)
)
else:
logger.warning(
"Defaulting to polling... Provide a dmaap url to receive faster updates"
)
# Add shutdown handlers for sigint and sigterm
for signame in ("SIGINT", "SIGTERM"):
sig = getattr(signal, signame)
loop.add_signal_handler(
sig,
lambda: asyncio.ensure_future(
shutdown_handler(loop, tasks, inventory)
),
)
# Start prometheus server daemonthread for metrics/healthchecking
if 'bind' in kwargs:
metrics_server = kwargs.get('metrics_server', start_http_server)
metrics_server(kwargs['bind'].port, addr=kwargs['bind'].hostname)
def start_event_loop(config):
"""
start the event loop that runs the application
:param config: Config object for the application
"""
loop = asyncio.get_event_loop()
inventory = Inventory(
config.filters,
config.ids,
config.out_file,
config.client
)
_setup_coroutines(
loop,
inventory,
shutdown,
task_runner,
metrics_server=start_http_server,
bind=config.bind,
check_period=config.check_period
)
loop.run_forever()
loop.close()
logger.info("shutdown complete")
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