Change the exception type from ValueError to IpamValueInvalid

The current ValueError in _validate_with_subnet will return an unfriendly
"Internal Server Error" to user who wrong configured the subnet and pool. This
patch introduces a new exception IpamValueInvalid and it will be mapped to an
meaningful webob exception.

Closes-Bug: #1531401

Change-Id: Ib50a4b3cd1881a0c364d354728fc43040c3ed520

neutron/ipam/exceptions.py

@@ -69,3 +69,9 @@ class IPAllocationFailed(exceptions.NeutronException):
 
 class IpamAvailabilityRangeNoChanges(exceptions.NeutronException):
     message = _("New value for first_ip or last_ip has to be specified.")
+
+
+class IpamValueInvalid(exceptions.Conflict):
+    def __init__(self, message=None):
+        self.message = message
+        super(IpamValueInvalid, self).__init__()

neutron/ipam/requests.py

@@ -110,16 +110,18 @@ class SubnetRequest(object):
             if (gw_ip.version == 4 or (gw_ip.version == 6
                                        and not gw_ip.is_link_local())):
                 if self.gateway_ip not in subnet_cidr:
-                    raise ValueError(_("gateway_ip is not in the subnet"))
+                    raise ipam_exc.IpamValueInvalid(_(
+                                        "gateway_ip %s is not in the subnet") %
+                                        self.gateway_ip)
 
         if self.allocation_pools:
             if subnet_cidr.version != self.allocation_pools[0].version:
-                raise ValueError(_("allocation_pools use the wrong ip "
-                                   "version"))
+                raise ipam_exc.IpamValueInvalid(_(
+                                "allocation_pools use the wrong ip version"))
             for pool in self.allocation_pools:
                 if pool not in subnet_cidr:
-                    raise ValueError(_("allocation_pools are not in the "
-                                       "subnet"))
+                    raise ipam_exc.IpamValueInvalid(_(
+                                "allocation_pools are not in the subnet"))
 
 
 class AnySubnetRequest(SubnetRequest):

neutron/tests/unit/db/test_db_base_plugin_v2.py

@@ -5560,6 +5560,23 @@ class TestSubnetPoolsV2(NeutronDbPluginV2TestCase):
         res = self.deserialize(self.fmt, req.get_response(self.api))
         self.assertEqual(1, res['subnetpool']['default_quota'])
 
+    def test_allocate_subnet_bad_gateway(self):
+        with self.network() as network:
+            sp = self._test_create_subnetpool(['10.10.0.0/8'],
+                                              tenant_id=self._tenant_id,
+                                              name=self._POOL_NAME,
+                                              default_prefixlen='24')
+
+            # Request a subnet allocation (no CIDR)
+            data = {'subnet': {'network_id': network['network']['id'],
+                               'subnetpool_id': sp['subnetpool']['id'],
+                               'prefixlen': 32,
+                               'ip_version': 4,
+                               'tenant_id': network['network']['tenant_id']}}
+            req = self.new_create_request('subnets', data)
+            result = req.get_response(self.api)
+            self.assertEqual(409, result.status_int)
+
     def test_allocate_any_subnet_with_prefixlen(self):
         with self.network() as network:
             sp = self._test_create_subnetpool(['10.10.0.0/16'],

neutron/tests/unit/ipam/test_requests.py

@@ -134,7 +134,7 @@ class TestIpamAnySubnetRequest(IpamSubnetRequestTestCase):
 
     def test_subnet_request_bad_gateway(self):
         cfg.CONF.set_override('force_gateway_on_subnet', True)
-        self.assertRaises(ValueError,
+        self.assertRaises(ipam_exc.IpamValueInvalid,
                           ipam_req.AnySubnetRequest,
                           self.tenant_id,
                           self.subnet_id,
@@ -153,7 +153,7 @@ class TestIpamAnySubnetRequest(IpamSubnetRequestTestCase):
 
     def test_subnet_request_allocation_pool_wrong_version(self):
         pools = [netaddr.IPRange('0.0.0.4', '0.0.0.5')]
-        self.assertRaises(ValueError,
+        self.assertRaises(ipam_exc.IpamValueInvalid,
                           ipam_req.AnySubnetRequest,
                           self.tenant_id,
                           self.subnet_id,
@@ -163,7 +163,7 @@ class TestIpamAnySubnetRequest(IpamSubnetRequestTestCase):
 
     def test_subnet_request_allocation_pool_not_in_net(self):
         pools = [netaddr.IPRange('0.0.0.64', '0.0.0.128')]
-        self.assertRaises(ValueError,
+        self.assertRaises(ipam_exc.IpamValueInvalid,
                           ipam_req.AnySubnetRequest,
                           self.tenant_id,
                           self.subnet_id,
@@ -185,7 +185,7 @@ class TestIpamSpecificSubnetRequest(IpamSubnetRequestTestCase):
 
     def test_subnet_request_bad_gateway(self):
         cfg.CONF.set_override('force_gateway_on_subnet', True)
-        self.assertRaises(ValueError,
+        self.assertRaises(ipam_exc.IpamValueInvalid,
                           ipam_req.SpecificSubnetRequest,
                           self.tenant_id,
                           self.subnet_id,