slapformat: WIP: Add addressFromNetwork utility

slapos/format.py

@@ -603,8 +603,7 @@ class Interface(object):
       return ipaddress.IPv4Network(cidr, strict=False)
 
   def getPartitionIPv4Addr(self, index):
-    network = self.ipv4_network
-    return ipaddress.IPv4Interface((network[index + 2], network.prefixlen))
+    return addressFromNetwork(self.ipv4_network, index + 2)
 
   def getTapIPv4Network(self, conf):
     tap_gateway_interface = conf.tap_gateway_interface
@@ -634,7 +633,7 @@ class Interface(object):
   def getTapIPv4Gateway(self, _index):
     network = self.tap_ipv4_network
     if network:
-      return ipaddress.IPv4Interface((network[1], network.prefixlen))
+      return addressFromNetwork(network, 1)
 
   def getTapIPv4Range(self, index):
     network = self.tap_ipv4_network
@@ -681,12 +680,10 @@ class Interface(object):
     )
 
   def getComputerIPv6Addr(self):
-    network = self.ipv6_network
-    return ipaddress.IPv6Interface((network[1], network.prefixlen))
+    return addressFromNetwork(self.ipv6_network, 1)
 
   def getPartitionIPv6Addr(self, index):
-    network = self.ipv6_network
-    return ipaddress.IPv6Interface((network[index + 2], network.prefixlen))
+    return addressFromNetwork(self.ipv6_network, index + 2)
 
   def getPartitionIPv6Range(self, index):
     network = self.ipv6_network
@@ -782,6 +779,11 @@ def ensureDir(path, mode):
       raise
 
 
+def addressFromNetwork(network, index):
+  addr = network[index]
+  return ipaddress.ip_interface((addr, network.prefixlen))
+
+
 # Wrapping, Tracing & Dry-running
 
 class WrappedModule(object):