Added the ability to filter gce grouped_instances by region/zone (#14138)

contrib/inventory/gce.py

@@ -125,8 +125,10 @@ class GceInventory(object):
                     pretty=self.args.pretty))
             sys.exit(0)
 
+        zones = self.parse_env_zones()
+
         # Otherwise, assume user wants all instances grouped
-        print(self.json_format_dict(self.group_instances(),
+        print(self.json_format_dict(self.group_instances(zones),
             pretty=self.args.pretty))
         sys.exit(0)
 
@@ -233,6 +235,14 @@ class GceInventory(object):
         )
         return gce
 
+    def parse_env_zones(self):
+        '''returns a list of comma seperated zones parsed from the GCE_ZONE environment variable.
+        If provided, this will be used to filter the results of the grouped_instances call'''
+        import csv
+        reader = csv.reader([os.environ.get('GCE_ZONE',"")], skipinitialspace=True)
+        zones = [r for r in reader]
+        return [z for z in zones[0]]
+
     def parse_cli_args(self):
         ''' Command line argument processing '''
 
@@ -289,7 +299,7 @@ class GceInventory(object):
         except Exception as e:
             return None
 
-    def group_instances(self):
+    def group_instances(self, zones=None):
         '''Group all instances'''
         groups = {}
         meta = {}
@@ -312,6 +322,12 @@ class GceInventory(object):
             meta["hostvars"][name] = self.node_to_dict(node)
 
             zone = node.extra['zone'].name
+
+            # To avoid making multiple requests per zone
+            # we list all nodes and then filter the results
+            if zones and zone not in zones:
+                continue
+
             if groups.has_key(zone): groups[zone].append(name)
             else: groups[zone] = [name]