initial commit

[osm/common.git] / osm_common / msgkafka.py

diff --git a/osm_common/msgkafka.py b/osm_common/msgkafka.py
new file mode 100644 (file)
index 0000000..c819c81
--- /dev/null
+++ b/osm_common/msgkafka.py
@@ -0,0 +1,107 @@
+import logging
+import asyncio
+import yaml
+from aiokafka import AIOKafkaConsumer
+from aiokafka import AIOKafkaProducer
+from aiokafka.errors import KafkaError
+from msgbase import MsgBase, MsgException
+#import json
+
+__author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>, " \
+             "Guillermo Calvino <guillermo.calvinosanchez@altran.com>"
+class MsgKafka(MsgBase):
+    def __init__(self, logger_name='msg'):
+        self.logger = logging.getLogger(logger_name)
+        self.host = None
+        self.port = None
+        self.consumer = None
+        self.producer = None
+        self.loop = None
+        self.broker = None
+
+    def connect(self, config):
+        try:
+            if "logger_name" in config:
+                self.logger = logging.getLogger(config["logger_name"])
+            self.host = config["host"]
+            self.port = config["port"]
+            self.loop = asyncio.get_event_loop()
+            self.broker = str(self.host) + ":" + str(self.port)
+
+        except Exception as e:  # TODO refine
+            raise MsgException(str(e))
+
+    def disconnect(self):
+        try:
+            self.loop.close()
+        except Exception as e:  # TODO refine
+            raise MsgException(str(e))
+
+    def write(self, topic, key, msg):
+        try:
+            self.loop.run_until_complete(self.aiowrite(topic=topic, key=key,
+                                                       msg=yaml.safe_dump(msg, default_flow_style=True),
+                                                       loop=self.loop))
+
+        except Exception as e:
+            raise MsgException("Error writing {} topic: {}".format(topic, str(e)))
+
+    def read(self, topic):
+        """
+        Read from one or several topics. it is non blocking returning None if nothing is available
+        :param topic: can be str: single topic; or str list: several topics
+        :return: topic, key, message; or None
+        """
+        try:
+            return self.loop.run_until_complete(self.aioread(topic, self.loop))
+        except MsgException:
+            raise
+        except Exception as e:
+            raise MsgException("Error reading {} topic: {}".format(topic, str(e)))
+
+    async def aiowrite(self, topic, key, msg, loop=None):
+
+        if not loop:
+            loop = self.loop
+        try:
+            self.producer = AIOKafkaProducer(loop=loop, key_serializer=str.encode, value_serializer=str.encode,
+                                             bootstrap_servers=self.broker)
+            await self.producer.start()
+            await self.producer.send(topic=topic, key=key, value=msg)
+        except Exception as e:
+            raise MsgException("Error publishing to {} topic: {}".format(topic, str(e)))
+        finally:
+            await self.producer.stop()
+
+    async def aioread(self, topic, loop=None, callback=None, *args):
+        """
+        Asyncio read from one or several topics. It blocks
+        :param topic: can be str: single topic; or str list: several topics
+        :param loop: asyncio loop
+        :callback: callback function that will handle the message in kafka bus
+        :*args: optional arguments for callback function
+        :return: topic, key, message
+        """
+
+        if not loop:
+            loop = self.loop
+        try:
+            if isinstance(topic, (list, tuple)):
+                topic_list = topic
+            else:
+                topic_list = (topic,)
+
+            self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker)
+            await self.consumer.start()
+            self.consumer.subscribe(topic_list)
+
+            async for message in self.consumer:
+                if callback:
+                    callback(message.topic, yaml.load(message.key), yaml.load(message.value), *args)
+                else:
+                    return message.topic, yaml.load(message.key), yaml.load(message.value)
+        except KafkaError as e:
+            raise MsgException(str(e))
+        finally:
+            await self.consumer.stop()
+