Fix pylint warnings

zoe_master/backends/docker/backend.py

@@ -59,8 +59,8 @@ class DockerEngineBackend(zoe_master.backends.base.BaseBackend):
 
     def spawn_service(self, service_instance: ServiceInstance):
         """Spawn a service, translating a Zoe Service into a Docker container."""
-        m = re.search(r'^(?:([^\/]+)\/)?(?:([^\/]+)\/)?([^@:\/]+)(?:[@:](.+))?$', service_instance.image_name)
-        if m.group(4) is None:
+        parsed_name = re.search(r'^(?:([^\/]+)\/)?(?:([^\/]+)\/)?([^@:\/]+)(?:[@:](.+))?$', service_instance.image_name)
+        if parsed_name.group(4) is None:
             raise ZoeStartExecutionFatalException('Image {} does not have a version tag'.format(service_instance.image_name))
         conf = self._get_config(service_instance.backend_host)
         try:
@@ -91,8 +91,8 @@ class DockerEngineBackend(zoe_master.backends.base.BaseBackend):
 
     def preload_image(self, image_name):
         """Pull an image from a Docker registry into each host. We shuffle the list to prevent the scheduler to find always the first host in the list."""
-        m = re.search(r'^(?:([^\/]+)\/)?(?:([^\/]+)\/)?([^@:\/]+)(?:[@:](.+))?$', image_name)
-        if m.group(4) is None:
+        parsed_name = re.search(r'^(?:([^\/]+)\/)?(?:([^\/]+)\/)?([^@:\/]+)(?:[@:](.+))?$', image_name)
+        if parsed_name.group(4) is None:
             raise ZoeException('Image {} does not have a version tag'.format(image_name))
         one_success = False
         for host_conf in self.docker_config:

zoe_master/backends/interface.py

@@ -16,8 +16,8 @@
 """The high-level interface that Zoe uses to talk to the configured container backend."""
 
 import logging
-from typing import List
 import time
+from typing import List
 
 from zoe_lib.config import get_conf
 from zoe_lib.state import Execution, Service, SQLManager  # pylint: disable=unused-import

zoe_master/backends/kubernetes/backend.py

@@ -74,3 +74,7 @@ class KubernetesBackend(zoe_master.backends.base.BaseBackend):
             node.memory_in_use = node.memory_reserved
             node.cores_in_use = node.cores_reserved
         return info
+
+    def preload_image(self, image_name: str) -> None:
+        """Make a service image available."""
+        raise NotImplementedError

zoe_master/backends/swarm/backend.py

@@ -75,3 +75,7 @@ class SwarmBackend(zoe_master.backends.base.BaseBackend):
     def service_log(self, service: Service):
         """Get the log."""
         return self.swarm.logs(service.backend_id, True, False)
+
+    def preload_image(self, image_name: str) -> None:
+        """Make a service image available."""
+        raise NotImplementedError