Implements filebased config, config override through env vars, use of osm

[osm/MON.git] / osm_mon / core / message_bus_client.py

diff --git a/osm_mon/core/message_bus_client.py b/osm_mon/core/message_bus_client.py
new file mode 100644 (file)
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+++ b/osm_mon/core/message_bus_client.py
@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2018 Whitestack, LLC
+# *************************************************************
+
+# This file is part of OSM Monitoring module
+# All Rights Reserved to Whitestack, LLC
+
+# 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.
+
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: bdiaz@whitestack.com or glavado@whitestack.com
+##
+import asyncio
+from typing import List, Callable
+
+from osm_common import msgkafka, msglocal
+
+from osm_mon.core.config import Config
+
+
+class MessageBusClient:
+    def __init__(self, config: Config, loop=None):
+        if config.get('message', 'driver') == "local":
+            self.msg_bus = msglocal.MsgLocal()
+        elif config.get('message', 'driver') == "kafka":
+            self.msg_bus = msgkafka.MsgKafka()
+        else:
+            raise Exception("Unknown message bug driver {}".format(config.get('section', 'driver')))
+        self.msg_bus.connect(config.get('message'))
+        if not loop:
+            loop = asyncio.get_event_loop()
+        self.loop = loop
+
+    async def aioread(self, topics: List[str], callback: Callable = None, **kwargs):
+        """
+        Retrieves messages continuously from bus and executes callback for each message consumed.
+        :param topics: List of message bus topics to consume from.
+        :param callback: Async callback function to be called for each message received.
+        :param kwargs: Keyword arguments to be passed to callback function.
+        :return: None
+        """
+        await self.msg_bus.aioread(topics, self.loop, aiocallback=callback, **kwargs)
+
+    async def aiowrite(self, topic: str, key: str, msg: dict):
+        """
+        Writes message to bus.
+        :param topic: Topic to write to.
+        :param key: Key to write to.
+        :param msg: Dictionary containing message to be written.
+        :return: None
+        """
+        await self.msg_bus.aiowrite(topic, key, msg, self.loop)
+
+    async def aioread_once(self, topic: str):
+        """
+        Retrieves last message from bus.
+        :param topic: topic to retrieve message from.
+        :return: tuple(topic, key, message)
+        """
+        result = await self.msg_bus.aioread(topic, self.loop)
+        return result