Validate requested region against region list

We have lists of valid regions for clouds, but specifying a region
incorrectly is a common mistake (specifying dfw instead of DFW,
for instance) Throw an error early with a helpful error message.

Change-Id: I55edf20c6dddde4a4d71dad33a41d4e10448ddac

2 files changed, 26 insertions, 1 deletions

diff --git a/os_client_config/config.py b/os_client_config/config.py
index bff2f5c..b2c1649 100644
--- a/os_client_config/config.py
+++ b/os_client_config/config.py
@@ -573,7 +573,15 @@ class OpenStackConfig(object):
 
         # Regions is a list that we can use to create a list of cloud/region
         # objects. It does not belong in the single-cloud dict
-        config.pop('regions', None)
+        regions = config.pop('regions', None)
+        if regions and args['region_name'] not in regions:
+            raise exceptions.OpenStackConfigException(
+                'Region {region_name} is not a valid region name for cloud'
+                ' {cloud}. Valid choices are {region_list}. Please note that'
+                ' region names are case sensitive.'.format(
+                    region_name=args['region_name'],
+                    region_list=','.join(regions),
+                    cloud=cloud))
 
         # Can't just do update, because None values take over
         for (key, val) in iter(args.items()):
diff --git a/os_client_config/tests/test_config.py b/os_client_config/tests/test_config.py
index 271c40b..0130748 100644
--- a/os_client_config/tests/test_config.py
+++ b/os_client_config/tests/test_config.py
@@ -298,6 +298,23 @@ class TestConfigArgparse(base.TestCase):
         self.assertEqual(cc.region_name, 'region1')
         self.assertIsNone(cc.snack_type)
 
+    def test_get_one_cloud_bad_region(self):
+        c = config.OpenStackConfig(config_files=[self.cloud_yaml],
+                                   vendor_files=[self.vendor_yaml])
+
+        self.assertRaises(
+            exceptions.OpenStackConfigException,
+            c.get_one_cloud,
+            cloud='_test_cloud_regions', region_name='bad')
+
+    def test_get_one_cloud_bad_region_no_regions(self):
+        c = config.OpenStackConfig(config_files=[self.cloud_yaml],
+                                   vendor_files=[self.vendor_yaml])
+
+        cc = c.get_one_cloud(cloud='_test-cloud_', region_name='bad_region')
+        self._assert_cloud_details(cc)
+        self.assertEqual(cc.region_name, 'bad_region')
+
     def test_get_one_cloud_no_argparse_region2(self):
         c = config.OpenStackConfig(config_files=[self.cloud_yaml],
                                    vendor_files=[self.vendor_yaml])