fix(api): account for NoneType when resource is gone

In versions prior to Kubernetes v1.5, an empty list was returned when a resource didn't exist. in
v1.5 it now returns a NoneType, so we need to account for that change and convert it back to an
empty list.

Author: Matthew Fisher

rootfs/api/models/app.py

@@ -281,9 +281,10 @@ def restart(self, **kwargs):  # noqa
                 desired = 0
                 labels = self._scheduler_filter(**kwargs)
                 # fetch RS (which represent Deployments)
-                controllers = self._scheduler.rs.get(kwargs['id'], labels=labels)
-
-                for controller in controllers.json()['items']:
+                controllers = self._scheduler.rs.get(kwargs['id'], labels=labels).json()['items']
+                if not controllers:
+                    controllers = []
+                for controller in controllers:
                     desired += controller['spec']['replicas']
         except KubeException:
             # Nothing was found
@@ -737,6 +738,8 @@ def list_pods(self, *args, **kwargs):
                 pods = [self._scheduler.pod.get(self.id, kwargs['name']).json()]
             else:
                 pods = self._scheduler.pod.get(self.id, labels=labels).json()['items']
+                if not pods:
+                    pods = []
 
             data = []
             for p in pods:

rootfs/api/models/release.py

@@ -263,8 +263,10 @@ def cleanup_old(self):  # noqa
         # Cleanup controllers
         labels = {'heritage': 'deis'}
         controller_removal = []
-        controllers = self._scheduler.rc.get(self.app.id, labels=labels).json()
-        for controller in controllers['items']:
+        controllers = self._scheduler.rc.get(self.app.id, labels=labels).json()['items']
+        if not controllers:
+            controllers = []
+        for controller in controllers:
             current_version = controller['metadata']['labels']['version']
             # skip the latest release
             if current_version == latest_version:
@@ -289,8 +291,10 @@ def cleanup_old(self):  # noqa
 
         # Remove stray pods
         labels = {'heritage': 'deis'}
-        pods = self._scheduler.pod.get(self.app.id, labels=labels).json()
-        for pod in pods['items']:
+        pods = self._scheduler.pod.get(self.app.id, labels=labels).json()['items']
+        if not pods:
+            pods = []
+        for pod in pods:
             if self._scheduler.pod.deleted(pod):
                 continue
 
@@ -319,8 +323,10 @@ def _cleanup_deployment_secrets_and_configs(self, namespace):
         # Find all ReplicaSets
         versions = []
         labels = {'heritage': 'deis', 'app': namespace}
-        replicasets = self._scheduler.rs.get(namespace, labels=labels).json()
-        for replicaset in replicasets['items']:
+        replicasets = self._scheduler.rs.get(namespace, labels=labels).json()['items']
+        if not replicasets:
+            replicasets = []
+        for replicaset in replicasets:
             if (
                 'version' not in replicaset['metadata']['labels'] or
                 replicaset['metadata']['labels']['version'] in versions
@@ -338,8 +344,10 @@ def _cleanup_deployment_secrets_and_configs(self, namespace):
             'version__notin': versions
         }
         self.app.log('Cleaning up orphaned env var secrets for application {}'.format(namespace), level=logging.DEBUG)  # noqa
-        secrets = self._scheduler.secret.get(namespace, labels=labels).json()
-        for secret in secrets['items']:
+        secrets = self._scheduler.secret.get(namespace, labels=labels).json()['items']
+        if not secrets:
+            secrets = []
+        for secret in secrets:
             self._scheduler.secret.delete(namespace, secret['metadata']['name'])
 
     def _delete_release_in_scheduler(self, namespace, version):
@@ -358,8 +366,10 @@ def _delete_release_in_scheduler(self, namespace, version):
         # see if the app config has deploy timeout preference, otherwise use global
         timeout = self.config.values.get('DEIS_DEPLOY_TIMEOUT', settings.DEIS_DEPLOY_TIMEOUT)
 
-        controllers = self._scheduler.rc.get(namespace, labels=labels).json()
-        for controller in controllers['items']:
+        controllers = self._scheduler.rc.get(namespace, labels=labels).json()['items']
+        if not controllers:
+            controllers = []
+        for controller in controllers:
             # Deployment takes care of this in the API, RC does not
             # Have the RC scale down pods and delete itself
             self._scheduler.rc.scale(namespace, controller['metadata']['name'], 0, timeout)

rootfs/scheduler/resources/deployment.py

@@ -224,7 +224,7 @@ def in_progress(self, namespace, name, timeout, batches, replicas, tags):
         # fetch the latest RS for Deployment and use the start time to compare to deploy timeout
         replicasets = self.rs.get(namespace, labels=labels).json()['items']
         # the labels should ensure that only 1 replicaset due to the version label
-        if len(replicasets) != 1:
+        if replicasets and len(replicasets) != 1:
             # if more than one then sort by start time to newest is first
             replicasets.sort(key=lambda x: x['metadata']['creationTimestamp'], reverse=True)
 
@@ -356,7 +356,8 @@ def _get_deploy_steps(self, batches, tags):
         # if there is no batch information available default to available nodes for app
         if not batches:
             # figure out how many nodes the application can go on
-            steps = len(self.node.get(labels=tags).json()['items'])
+            nodes = self.node.get(labels=tags).json()['items']
+            steps = len(nodes) if nodes else 0
         else:
             steps = int(batches)
 

rootfs/scheduler/resources/pod.py

@@ -485,10 +485,12 @@ def events(self, pod):
             'involvedObject.namespace': pod['metadata']['namespace'],
             'involvedObject.uid': pod['metadata']['uid']
         }
-        events = self.ns.events(pod['metadata']['namespace'], fields=fields).json()
+        events = self.ns.events(pod['metadata']['namespace'], fields=fields).json()['items']
+        if not events:
+            events = []
         # make sure that events are sorted
-        events['items'].sort(key=lambda x: x['lastTimestamp'])
-        return events['items']
+        events.sort(key=lambda x: x['lastTimestamp'])
+        return events
 
     def _handle_pod_errors(self, pod, reason, message):
         """
@@ -568,8 +570,10 @@ def _handle_pending_pods(self, namespace, labels):
         or throws errors as needed
         """
         timeout = 0
-        pods = self.get(namespace, labels=labels).json()
-        for pod in pods['items']:
+        pods = self.get(namespace, labels=labels).json()['items']
+        if not pods:
+            pods = []
+        for pod in pods:
             # only care about pods that are not starting or in the starting phases
             if pod['status']['phase'] not in ['Pending', 'ContainerCreating']:
                 continue
@@ -612,14 +616,16 @@ def wait_until_terminated(self, namespace, labels, current, desired):
         delta = current - desired
         self.log(namespace, "waiting for {} pods to be terminated ({}s timeout)".format(delta, timeout))  # noqa
         for waited in range(timeout):
-            pods = self.get(namespace, labels=labels).json()
-            count = len(pods['items'])
+            pods = self.get(namespace, labels=labels).json()['items']
+            if not pods:
+                pods = []
+            count = len(pods)
 
             # see if any pods are past their terminationGracePeriodsSeconds (as in stuck)
             # seems to be a problem in k8s around that:
             # https://github.com/kubernetes/kubernetes/search?q=terminating&type=Issues
             # these will be eventually GC'ed by k8s, ignoring them for now
-            for pod in pods['items']:
+            for pod in pods:
                 # remove pod if it is passed the graceful termination period
                 if self.deleted(pod):
                     count -= 1
@@ -655,8 +661,10 @@ def wait_until_ready(self, namespace, containers, labels, desired, timeout):  #
                 self.log(namespace, 'Increasing timeout by {}s to allow a pull image operation to finish for pods'.format(additional_timeout))  # noqa
 
             count = 0  # ready pods
-            pods = self.get(namespace, labels=labels).json()
-            for pod in pods['items']:
+            pods = self.get(namespace, labels=labels).json()['items']
+            if not pods:
+                pods = []
+            for pod in pods:
                 # now that state is running time to see if probes are passing
                 if self.ready(pod):
                     count += 1
@@ -691,8 +699,10 @@ def _handle_not_ready_pods(self, namespace, labels):
         Detects if any pod is in the Running phase but not Ready and handles
         any potential issues around that mainly failed healthcheks
         """
-        pods = self.get(namespace, labels=labels).json()
-        for pod in pods['items']:
+        pods = self.get(namespace, labels=labels).json()['items']
+        if not pods:
+            pods = []
+        for pod in pods:
             # only care about pods that are in running phase
             if pod['status']['phase'] != 'Running':
                 continue
@@ -703,8 +713,8 @@ def _handle_not_ready_pods(self, namespace, labels):
             if container is None or container['ready'] == 'true':
                 continue
 
-            for event in self.events(pod):
-                if event['reason'] == 'Unhealthy':
+                for event in self.events(pod):
+                    if event['reason'] == 'Unhealthy':
                     # strip out whitespaces on either side
                     message = "\n".join([x.strip() for x in event['message'].split("\n")])
                     raise KubeException(message)