CORD-2965 Kubernetes Synchronizer

Change-Id: Ie5c02b9ad1c65af686598bab0b36350ac1caef64
diff --git a/xos/synchronizer/steps/sync_trustdomain.py b/xos/synchronizer/steps/sync_trustdomain.py
new file mode 100644
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+++ b/xos/synchronizer/steps/sync_trustdomain.py
@@ -0,0 +1,90 @@
+
+# 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.
+
+"""
+    sync_trustdomain.py
+
+    Synchronize TrustDomain. TrustDomains correspond roughly to Kubernetes namespaces.
+"""
+
+from synchronizers.new_base.syncstep import SyncStep
+from synchronizers.new_base.modelaccessor import TrustDomain
+
+from xosconfig import Config
+from multistructlog import create_logger
+
+from kubernetes.client.rest import ApiException
+from kubernetes import client as kubernetes_client, config as kubernetes_config
+
+log = create_logger(Config().get('logging'))
+
+class SyncTrustDomain(SyncStep):
+
+    """
+        SyncTrustsDomain
+
+        Implements sync step for syncing trust domains.
+    """
+
+    provides = [TrustDomain]
+    observes = TrustDomain
+    requested_interval = 0
+
+    def __init__(self, *args, **kwargs):
+        super(SyncTrustDomain, self).__init__(*args, **kwargs)
+        kubernetes_config.load_incluster_config()
+        self.v1 = kubernetes_client.CoreV1Api()
+
+    def fetch_pending(self, deleted):
+        """ Figure out which TrustDomains are interesting to the K8s synchronizer. It's necessary to filter as we're
+            synchronizing a core model, and we only want to synchronize trust domains that will exist within
+            Kubernetes.
+        """
+        objs = super(SyncTrustDomain, self).fetch_pending(deleted)
+        for obj in objs[:]:
+            # If the TrustDomain isn't part of the K8s service, then it's someone else's trust domain
+            if "KubernetesService" not in obj.owner.leaf_model.class_names:
+                objs.remove(obj)
+        return objs
+
+    def get_namespace(self, o):
+        """ Give an XOS TrustDomain object, return the corresponding namespace from Kubernetes.
+            Return None if no namespace exists.
+        """
+        try:
+            ns = self.v1.read_namespace(o.name)
+        except ApiException, e:
+            if e.status == 404:
+                return None
+            raise
+        return ns
+
+    def sync_record(self, o):
+            ns = self.get_namespace(o)
+            if not ns:
+                ns = kubernetes_client.V1Namespace()
+                ns.metadata = kubernetes_client.V1ObjectMeta(name=o.name)
+
+                log.info("creating namespace %s" % o.name)
+                ns=self.v1.create_namespace(ns)
+
+            if (not o.backend_handle):
+                o.backend_handle = ns.metadata.self_link
+                o.save(update_fields=["backend_handle"])
+
+    def delete_record(self, port):
+        # TODO(smbaker): Implement delete step
+        pass
+