SEBA-169 Push kafka events when Kubernetes pods are created, updated, or destroyed

Change-Id: Idd711140c919ba2c232c7f08f0dc23507cfdd973
diff --git a/xos/synchronizer/pull_steps/pull_pods.py b/xos/synchronizer/pull_steps/pull_pods.py
index 3cbbbce..047fb10 100644
--- a/xos/synchronizer/pull_steps/pull_pods.py
+++ b/xos/synchronizer/pull_steps/pull_pods.py
@@ -18,6 +18,8 @@
     Implements a syncstep to pull information about pods form Kubernetes.
 """
 
+import json
+
 from synchronizers.new_base.pullstep import PullStep
 from synchronizers.new_base.modelaccessor import KubernetesServiceInstance, KubernetesService, Slice, Principal, \
                                                  TrustDomain, Site, Image
@@ -38,6 +40,14 @@
 
     def __init__(self):
         super(KubernetesServiceInstancePullStep, self).__init__(observed_model=KubernetesServiceInstance)
+
+        self.kafka_producer = None
+        if Config.get("event_bus.endpoint"):
+            try:
+                self.init_kafka_producer()
+            except:
+                log.exception("Failed to initialize Kafka producer")
+
         self.init_kubernetes_client()
 
     def init_kubernetes_client(self):
@@ -47,6 +57,21 @@
         self.v1apps = kubernetes_client.AppsV1Api()
         self.v1batch = kubernetes_client.BatchV1Api()
 
+    def init_kafka_producer(self):
+        from kafka import KafkaProducer
+        eventbus_kind = Config.get("event_bus.kind")
+        eventbus_endpoint = Config.get("event_bus.endpoint")
+
+        if not eventbus_kind:
+            log.error("Eventbus kind is not configured in synchronizer config file.")
+            return
+
+        if eventbus_kind not in ["kafka"]:
+            log.error("Eventbus kind is set to a technology we do not implement.", eventbus_kind=eventbus_kind)
+            return
+
+        self.kafka_producer = KafkaProducer(bootstrap_servers = [eventbus_endpoint])
+
     def obj_to_handle(self, obj):
         """ Convert a Kubernetes resource into a handle that we can use to uniquely identify the object within
             Kubernetes.
@@ -189,6 +214,26 @@
         else:
             return None
 
+    def send_notification(self, xos_pod, k8s_pod, status):
+        if not self.kafka_producer:
+            return
+
+        event = {"status": status,
+                 "name": xos_pod.name}
+
+        if xos_pod.id:
+            event["kubernetesserviceinstance_id"] = xos_pod.id
+
+        if k8s_pod:
+            event["labels"] = k8s_pod.metadata.labels
+
+            if k8s_pod.status.pod_ip:
+                event["netinterfaces"] = [{"name": "primary",
+                                          "addresses": [k8s_pod.status.pod_ip]}]
+
+        self.kafka_producer.send("xos.kubernetes.pod-details", json.dumps(event))
+        self.kafka_producer.flush()
+
     def pull_records(self):
         # Read all pods from Kubernetes, store them in k8s_pods_by_name
         k8s_pods_by_name = {}
@@ -233,27 +278,50 @@
                                                         slice = slice,
                                                         image = image,
                                                         backend_handle = self.obj_to_handle(pod),
-                                                        xos_managed = False)
+                                                        xos_managed = False,
+                                                        need_event = True)
                     xos_pod.save()
                     xos_pods_by_name[k] = xos_pod
                     log.info("Created XOS POD %s" % xos_pod.name)
 
+                xos_pod = xos_pods_by_name[k]
+
                 # Check to see if the ip address has changed. This can happen for pods that are managed by XOS. The IP
                 # isn't available immediately when XOS creates a pod, but shows up a bit later. So handle that case
                 # here.
-                xos_pod = xos_pods_by_name[k]
                 if (pod.status.pod_ip is not None) and (xos_pod.pod_ip != pod.status.pod_ip):
                     xos_pod.pod_ip = pod.status.pod_ip
-                    xos_pod.save(update_fields = ["pod_ip"])
+                    xos_pod.need_event = True # Trigger a new kafka event
+                    xos_pod.save(update_fields = ["pod_ip", "need_event"])
+                    log.info("Updated XOS POD %s" % xos_pod.name)
+
+                # Check to see if we haven't sent the Kafka event yet. It's possible Kafka could be down. If
+                # so, then we'll try to send the event again later.
+                if (xos_pod.need_event) and (self.kafka_producer):
+                    if xos_pod.last_event_sent == "created":
+                        event_kind = "updated"
+                    else:
+                        event_kind = "created"
+
+                    self.send_notification(xos_pod, pod, event_kind)
+
+                    xos_pod.need_event = False
+                    xos_pod.last_event_sent = event_kind
+                    xos_pod.save(update_fields=["need_event", "last_event_sent"])
+
             except:
                 log.exception("Failed to process k8s pod", k=k, pod=pod)
 
         # For each xos pod, see if there is no k8s pod. If that's the case, then the pud must have been deleted.
         for (k,xos_pod) in xos_pods_by_name.items():
-            if (not k in k8s_pods_by_name):
-                if (xos_pod.xos_managed):
-                    # Should we do something so it gets re-created by the syncstep?
-                    pass
-                else:
-                    xos_pod.delete()
-                    log.info("Deleted XOS POD %s" % k)
+            try:
+                if (not k in k8s_pods_by_name):
+                    if (xos_pod.xos_managed):
+                        # Should we do something so it gets re-created by the syncstep?
+                        pass
+                    else:
+                        self.send_notification(xos_pod, None, "deleted")
+                        xos_pod.delete()
+                        log.info("Deleted XOS POD %s" % k)
+            except:
+                log.exception("Failed to process xos pod", k=k, xos_pod=xos_pod)