Some general cleanup

cm_service_restart.py

@@ -7,26 +7,17 @@
 import cm_api
 from cm_api.api_client import ApiResource
 
-parser = argparse.ArgumentParser(description='Restart a CM cluster service')
 
-parser.add_argument('-m', '--cm_host', required=True,
-                    help="hostname / fqdn of the CM UI ('cloudera.domain.com')")
-parser.add_argument('-u', '--username', default=os.environ['USER'],
-                    help="username for the CM API authentication ('johndoe')")
-parser.add_argument('-p', '--password', required=True,
-                    help="password for the CM API authentication ('Pa55w0rd')")
-parser.add_argument('-l', '--cluster', required=False,
-                    help="cluster to restart service in ('mycluster')")
-parser.add_argument('-s', '--service', required=False,
-                    help="service to restart ('hdfs')")
+def select_from_items(item_type, items):
+    """Displays a list of items to choose from
 
-args = parser.parse_args()
-print args
+    Keyword arguments:
 
-# https://cloudera.github.io/cm_api/docs/quick-start/
-api = ApiResource(args.cm_host, username=args.username, password=args.password)
+    item_type -- What kind of item you are choosing. Displayed to user.
+    item -- List of choices
 
-def select_from_items(item_type, items):
+    returns selected item
+    """
     print("\n".join(["Choose a %s" % item_type] + [i.lower() for i in items]))
     item = raw_input().lower()
     print "Input received: %s" % item
@@ -36,31 +27,55 @@ def select_from_items(item_type, items):
         print 'Bad input received...'
         return select_from_items(item_type, items)
 
-# Get the cluster
-clusters = api.get_all_clusters()
-cluster_names = [c.name.lower() for c in clusters]
-cluster_name = ''
-if args.cluster is not None:
-    cluster_name = args.cluster.lower()
-else:
-    cluster_name = select_from_items('cluster', cluster_names)
-
-for cluster in clusters:
-    if cluster.name.lower() == cluster_name:
-
-        # Get the service
-        services = cluster.get_all_services()
-        service_names = [s.name.lower() for s in services]
-        service_name = ''
-        if args.service is not None:
-            service_name = args.service.lower()
-        else:
-            service_name = select_from_items('service', service_names)
-        for service in services:
-            if service.name.lower() == service_name:
-
-                # Restart the service
-                print "Attempting to restart '%s' in '%s'" % (service_name, cluster_name)
-                command = service.restart().wait()
-                print command
-                sys.exit()
+def main():
+    """Main execution path"""
+    parser = argparse.ArgumentParser(description='Restart a CM cluster service')
+
+    parser.add_argument('-m', '--cm_host', required=True,
+                        help="hostname / fqdn of the CM UI ('cloudera.domain.com')")
+    parser.add_argument('-u', '--username', default=os.environ['USER'],
+                        help="username for the CM API authentication ('johndoe')")
+    parser.add_argument('-p', '--password', required=True,
+                        help="password for the CM API authentication ('Pa55w0rd')")
+    parser.add_argument('-l', '--cluster', required=False,
+                        help="cluster to restart service in ('mycluster')")
+    parser.add_argument('-s', '--service', required=False,
+                        help="service to restart ('hdfs')")
+
+    args = parser.parse_args()
+    print args
+
+    # https://cloudera.github.io/cm_api/docs/quick-start/
+    api = ApiResource(args.cm_host, username=args.username, password=args.password)
+
+    # Get the cluster
+    clusters = api.get_all_clusters()
+    cluster_names = [c.name.lower() for c in clusters]
+    cluster_name = ''
+    if args.cluster is not None:
+        cluster_name = args.cluster.lower()
+    else:
+        cluster_name = select_from_items('cluster', cluster_names)
+
+    for cluster in clusters:
+        if cluster.name.lower() == cluster_name:
+
+            # Get the service
+            services = cluster.get_all_services()
+            service_names = [s.name.lower() for s in services]
+            service_name = ''
+            if args.service is not None:
+                service_name = args.service.lower()
+            else:
+                service_name = select_from_items('service', service_names)
+            for service in services:
+                if service.name.lower() == service_name:
+
+                    # Restart the service
+                    print "Attempting to restart '%s' in '%s'" % (service_name, cluster_name)
+                    command = service.restart().wait()
+                    print command
+                    sys.exit()
+
+if __name__ == "__main__":
+    main()