NSX|V: make use of granular API for getting DHCP binding

NSX 6.2.8 and 6.3.3 support the granular API:

New GET api:

GET https://<nsxmanagerIp>/api/4.0/edges/<edge-id>/dhcp/config/bindings/<binding-id>
RESPONSE:
           <staticBinding>
                <autoConfigureDNS>false</autoConfigureDNS>
                <leaseTime>86400</leaseTime>
                <subnetMask>255.255.255.0</subnetMask>
                <bindingId>binding-1</bindingId>
                <vmId>vm-34</vmId>
                <vnicId>1</vnicId>
                <hostname>test</hostname>
                <vmName>3-vm_ubuntu_1404_srv_64-shared-1668-02458540-04f1-4508-8037-2f2ce5542b91</vmName>
                <ipAddress>12.12.12.1</ipAddress>
           </staticBinding>

2) Quering a binding with a invalid ID:
   GET https://<nsxmanagerIp>/api/4.0/edges/<edge-id>/dhcp/config/bindings/<binding-id>
   RESPONSE:
           <error>
                <details>[Dhcp] Static binding is not found: binding-2</details>
                <errorCode>12510</errorCode>
                <moduleName>vShield Edge</moduleName>
         </error>

Change-Id: If1049035797c525344c46e1ae7f664a7b9daa4a1

vmware_nsx/common/utils.py

@@ -91,6 +91,15 @@ def is_nsxv_version_6_3(nsx_version):
             version.LooseVersion('6.3'))
 
 
+def is_nsxv_dhcp_binding_supported(nsx_version):
+    return ((version.LooseVersion(nsx_version) >=
+             version.LooseVersion('6.3.3')) or
+            (version.LooseVersion(nsx_version) >=
+             version.LooseVersion('6.2.8') and
+             version.LooseVersion(nsx_version) <
+             version.LooseVersion('6.3')))
+
+
 def get_tags(**kwargs):
     tags = ([dict(tag=value, scope=key)
             for key, value in six.iteritems(kwargs)])

vmware_nsx/plugins/nsx_v/vshield/edge_utils.py

@@ -2118,7 +2118,7 @@ def get_dhcp_binding_mappings_for_hostname(nsxv_manager, edge_id):
     return bindings_get
 
 
-def get_dhcp_binding_for_binding_id(nsxv_manager, edge_id, binding_id):
+def _get_dhcp_binding_for_binding_id(nsxv_manager, edge_id, binding_id):
     dhcp_config = query_dhcp_service_config(nsxv_manager, edge_id)
     if dhcp_config:
         for binding in dhcp_config['staticBindings']['staticBindings']:
@@ -2126,6 +2126,25 @@ def get_dhcp_binding_for_binding_id(nsxv_manager, edge_id, binding_id):
                 return binding
 
 
+def _get_dhcp_binding(nsxv_manager, edge_id, binding_id):
+    try:
+        h, dhcp_binding = nsxv_manager.vcns.get_dhcp_binding(edge_id,
+                                                             binding_id)
+        return dhcp_binding
+    except Exception:
+        return
+
+
+def get_dhcp_binding_for_binding_id(nsxv_manager, edge_id, binding_id):
+    # API for specific binding is supported in NSX 6.2.8 and 6.3.3 onwards
+    ver = nsxv_manager.vcns.get_version()
+    if c_utils.is_nsxv_dhcp_binding_supported(ver):
+        return _get_dhcp_binding(nsxv_manager, edge_id, binding_id)
+    else:
+        return _get_dhcp_binding_for_binding_id(nsxv_manager, edge_id,
+                                                binding_id)
+
+
 def query_dhcp_service_config(nsxv_manager, edge_id):
     """Retrieve the current DHCP configuration from the edge."""
     _, dhcp_config = nsxv_manager.vcns.query_dhcp_configuration(edge_id)

vmware_nsx/plugins/nsx_v/vshield/vcns.py

@@ -561,6 +561,13 @@ class Vcns(object):
                                    binding_id)
         return self.do_request(HTTP_DELETE, uri, decode=False)
 
+    def get_dhcp_binding(self, edge_id, binding_id):
+        """Get a dhcp static binding from the edge."""
+        uri = self._build_uri_path(edge_id,
+                                   DHCP_SERVICE, DHCP_BINDING_RESOURCE,
+                                   binding_id)
+        return self.do_request(HTTP_GET, uri, decode=False)
+
     def create_security_group(self, request):
         """Creates a security group container in nsx.
 

vmware_nsx/tests/unit/nsx_v/vshield/fake_vcns.py

@@ -304,6 +304,15 @@ class FakeVcns(object):
         response = ''
         return (header, response)
 
+    def get_dhcp_binding(self, edge_id, binding_id):
+        if binding_id not in self._dhcp_bindings[edge_id]:
+            raise Exception(_("binding %s does not exist") % binding_id)
+        response = self._dhcp_bindings[edge_id][binding_id]
+        header = {
+            'status': 200
+        }
+        return (header, response)
+
     def create_bridge(self, edge_id, request):
         if edge_id not in self._edges:
             raise Exception(_("Edge %s does not exist") % edge_id)