Merge pull request #1830 from mhank/1822-reformat-hosts

Fix format in which hosts are being stored for Swarm services

docker/types/services.py

@@ -137,7 +137,7 @@ class ContainerSpec(dict):
         if labels is not None:
             self['Labels'] = labels
         if hosts is not None:
-            self['Hosts'] = format_extra_hosts(hosts)
+            self['Hosts'] = format_extra_hosts(hosts, task=True)
 
         if mounts is not None:
             parsed_mounts = []

docker/utils/utils.py

@@ -571,7 +571,13 @@ def format_environment(environment):
     return [format_env(*var) for var in six.iteritems(environment)]
 
 
-def format_extra_hosts(extra_hosts):
+def format_extra_hosts(extra_hosts, task=False):
+    # Use format dictated by Swarm API if container is part of a task
+    if task:
+        return [
+            '{} {}'.format(v, k) for k, v in sorted(six.iteritems(extra_hosts))
+        ]
+
     return [
         '{}:{}'.format(k, v) for k, v in sorted(six.iteritems(extra_hosts))
     ]

tests/integration/api_service_test.py

@@ -588,8 +588,8 @@ class ServiceTest(BaseAPIIntegrationTest):
         assert 'Hosts' in svc_info['Spec']['TaskTemplate']['ContainerSpec']
         hosts = svc_info['Spec']['TaskTemplate']['ContainerSpec']['Hosts']
         assert len(hosts) == 2
-        assert 'foobar:127.0.0.1' in hosts
-        assert 'baz:8.8.8.8' in hosts
+        assert '127.0.0.1 foobar' in hosts
+        assert '8.8.8.8 baz' in hosts
 
     @requires_api_version('1.25')
     def test_create_service_with_hostname(self):