Seed policysync container code

For use by helm microservices to receive policy

Issue-ID: DCAEGEN2-2556
Change-Id: I2d9cb92ab480a90c63a9d8e6242848f7ca2df0f3
Signed-off-by: cluckenbaugh <cl5597@att.com>

1 files changed, 182 insertions, 0 deletions

diff --git a/dcae-services-policy-sync/policysync/coroutines.py b/dcae-services-policy-sync/policysync/coroutines.py
new file mode 100644
index 0000000..236d6f2
--- /dev/null
+++ b/dcae-services-policy-sync/policysync/coroutines.py
@@ -0,0 +1,182 @@
+# ============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")