Check API version before setting swarm addr pool.

Also corrected a documentation error: the default API version from
constants is currently 1.35, not 1.30 as was sometimes listed.
Signed-off-by: Barry Shapira <barry@whiterabbit.ai>

Removed accidental whitespace.
Signed-off-by: Barry Shapira <barry@whiterabbit.ai>

docker/api/swarm.py

 import logging
 from six.moves import http_client
+from ..constants import DEFAULT_SWARM_ADDR_POOL, DEFAULT_SWARM_SUBNET_SIZE
 from .. import errors
 from .. import types
 from .. import utils
@@ -82,7 +83,7 @@ class SwarmApiMixin(object):
 
     @utils.minimum_version('1.24')
     def init_swarm(self, advertise_addr=None, listen_addr='0.0.0.0:2377',
-                   default_addr_pool=[], subnet_size=24,
+                   default_addr_pool=None, subnet_size=None,
                    force_new_cluster=False, swarm_spec=None):
         """
         Initialize a new Swarm using the current connected engine as the first
@@ -106,9 +107,9 @@ class SwarmApiMixin(object):
             default_addr_pool (list of strings): Default Address Pool specifies
                 default subnet pools for global scope networks. Each pool
                 should be specified as a CIDR block, like '10.0.0.0/16'.
-                Default: []
+                Default: None
             subnet_size (int): SubnetSize specifies the subnet size of the
-                networks created from the default subnet pool. Default: 24
+                networks created from the default subnet pool. Default: None
             force_new_cluster (bool): Force creating a new Swarm, even if
                 already part of one. Default: False
             swarm_spec (dict): Configuration settings of the new Swarm. Use
@@ -124,8 +125,28 @@ class SwarmApiMixin(object):
         """
 
         url = self._url('/swarm/init')
+
         if swarm_spec is not None and not isinstance(swarm_spec, dict):
             raise TypeError('swarm_spec must be a dictionary')
+
+        if default_addr_pool is not None:
+            if utils.version_lt(self._version, '1.39'):
+                raise errors.InvalidVersion(
+                    'Address pool is only available for API version >= 1.39'
+                )
+            # subnet_size becomes 0 if not set with default_addr_pool
+            if subnet_size is None:
+                subnet_size = DEFAULT_SWARM_SUBNET_SIZE
+
+        if subnet_size is not None:
+            if utils.version_lt(self._version, '1.39'):
+                raise errors.InvalidVersion(
+                    'Subnet size is only available for API version >= 1.39'
+                )
+            # subnet_size is ignored if set without default_addr_pool
+            if default_addr_pool is None:
+                default_addr_pool = DEFAULT_SWARM_ADDR_POOL
+
         data = {
             'AdvertiseAddr': advertise_addr,
             'ListenAddr': listen_addr,

docker/constants.py

@@ -25,3 +25,6 @@ DEFAULT_NUM_POOLS = 25
 DEFAULT_NUM_POOLS_SSH = 9
 
 DEFAULT_DATA_CHUNK_SIZE = 1024 * 2048
+
+DEFAULT_SWARM_ADDR_POOL = ['10.0.0.0/8']
+DEFAULT_SWARM_SUBNET_SIZE = 24

docker/models/swarm.py

@@ -34,7 +34,7 @@ class Swarm(Model):
     get_unlock_key.__doc__ = APIClient.get_unlock_key.__doc__
 
     def init(self, advertise_addr=None, listen_addr='0.0.0.0:2377',
-             default_addr_pool=[], subnet_size=24,
+             default_addr_pool=None, subnet_size=None,
              force_new_cluster=False, **kwargs):
         """
         Initialize a new swarm on this Engine.
@@ -58,9 +58,9 @@ class Swarm(Model):
             default_addr_pool (list of str): Default Address Pool specifies
                 default subnet pools for global scope networks. Each pool
                 should be specified as a CIDR block, like '10.0.0.0/16'.
-                Default: []
+                Default: None
             subnet_size (int): SubnetSize specifies the subnet size of the
-                networks created from the default subnet pool. Default: 24
+                networks created from the default subnet pool. Default: None
             force_new_cluster (bool): Force creating a new Swarm, even if
                 already part of one. Default: False
             task_history_retention_limit (int): Maximum number of tasks

tests/integration/api_swarm_test.py

@@ -37,26 +37,31 @@ class SwarmTest(BaseAPIIntegrationTest):
 
     @requires_api_version('1.39')
     def test_init_swarm_custom_addr_pool(self):
+        # test defaults
         assert self.init_swarm()
         results_1 = self.client.inspect_swarm()
-        assert results_1['DefaultAddrPool'] is None
+        assert set(results_1['DefaultAddrPool']) == {'10.0.0.0/8'}
         assert results_1['SubnetSize'] == 24
-
+        # test addr pool alone
         assert self.init_swarm(default_addr_pool=['2.0.0.0/16'],
                                force_new_cluster=True)
         results_2 = self.client.inspect_swarm()
-        assert set(results_2['DefaultAddrPool']) == (
-            {'2.0.0.0/16'}
-        )
+        assert set(results_2['DefaultAddrPool']) == {'2.0.0.0/16'}
         assert results_2['SubnetSize'] == 24
-
+        # test subnet size alone
+        assert self.init_swarm(subnet_size=26,
+                               force_new_cluster=True)
+        results_3 = self.client.inspect_swarm()
+        assert set(results_3['DefaultAddrPool']) == {'10.0.0.0/8'}
+        assert results_3['SubnetSize'] == 26
+        # test both arguments together
         assert self.init_swarm(default_addr_pool=['2.0.0.0/16', '3.0.0.0/16'],
                                subnet_size=28, force_new_cluster=True)
-        results_3 = self.client.inspect_swarm()
-        assert set(results_3['DefaultAddrPool']) == (
+        results_4 = self.client.inspect_swarm()
+        assert set(results_4['DefaultAddrPool']) == (
             {'2.0.0.0/16', '3.0.0.0/16'}
         )
-        assert results_3['SubnetSize'] == 28
+        assert results_4['SubnetSize'] == 28
 
     @requires_api_version('1.24')
     def test_init_already_in_cluster(self):