[CORD-3056] Listen for ONU events

Change-Id: I304b382718ed43d21708ac8a2eaaed51b87c6af9
diff --git a/xos/synchronizer/event_steps/onu_event.py b/xos/synchronizer/event_steps/onu_event.py
new file mode 100644
index 0000000..458333f
--- /dev/null
+++ b/xos/synchronizer/event_steps/onu_event.py
@@ -0,0 +1,85 @@
+
+# Copyright 2017-present Open Networking Foundation
+#
+# 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.
+
+
+import json
+import os
+import sys
+from synchronizers.new_base.eventstep import EventStep
+from synchronizers.new_base.modelaccessor import VOLTService, ONUDevice, Service, model_accessor
+
+# from xos.exceptions import XOSValidationError
+
+
+# Manually send the event
+
+# import json
+# from kafka import KafkaProducer
+
+# event = json.dumps({
+#     'status': 'activate',
+#     'serial_number': 'BRCM1234',
+#     'uni_port_of_id': 'of:00100101',
+#     'of_dpid': 'of:109299321'
+# })
+# producer = KafkaProducer(bootstrap_servers="cord-kafka-kafka")
+# producer.send("onu.events", event)
+# producer.flush()
+
+
+class ONUEventStep(EventStep):
+    topics = ["onu.events"]
+    technology = "kafka"
+
+    def __init__(self, *args, **kwargs):
+        super(ONUEventStep, self).__init__(*args, **kwargs)
+
+    def get_oss_service(self, onu_serial_number):
+        try:
+            onu = ONUDevice.objects.get(serial_number=onu_serial_number)
+        except IndexError as e:
+            raise Exception("No ONUDevice with serial_number %s is present in XOS" % onu_serial_number)
+
+        volt_service = onu.pon_port.olt_device.volt_service
+        service = Service.objects.get(id=volt_service.id)
+        osses = [s for s in service.provider_services if s.kind.lower() == "oss"]
+
+        if len(osses) > 1:
+            self.log.warn("More than one OSS found for %s" % volt_service.name)
+        try:
+            return osses[0].leaf_model
+        except IndexError as e:
+            return None
+
+    def handle_onu_activate_event(self, event):
+        oss = self.get_oss_service(event["serial_number"])
+
+        if not oss:
+            self.log.info("Not processing events as no OSS service is present (is it a provider of vOLT?")
+        else:
+            try:
+                oss.validate_onu(event)
+            except Exception, e:
+                self.log.exception("Failing to validate ONU in OSS Service %s" % oss.name)
+                raise e
+
+    def process_event(self, event):
+        value = json.loads(event.value)
+        self.log.info("onu.events: received event", value=value)
+
+        if value["status"] == "activate":
+            self.log.info("onu.events: activate onu", value=value)
+            self.handle_onu_activate_event(value)
+