free_port: updates recipe to use getValueFromPreviousRun from GenericBaseRecipe

slapos/recipe/free_port.py

@@ -25,12 +25,13 @@
 #
 ##############################################################################
 
-import ConfigParser
 import os
 import netaddr
 import socket
 
-class Recipe(object):
+from slapos.recipe.librecipe.generic import GenericBaseRecipe
+
+class Recipe(GenericBaseRecipe):
   """
   Uses the socket python standard library to get an unused port.
 
@@ -48,17 +49,13 @@ class Recipe(object):
     # If this check isn't done, a new port would be picked for every upgrade
     # of the software release
     try:
-      parser = ConfigParser.RawConfigParser()
-      if os.path.exists(buildout['buildout']['installed']):
-        with open(buildout['buildout']['installed']) as config_file:
-          parser.readfp(config_file)
-        port = parser.get(name, 'port')
-        # Port can be 0 in case of upgrade: some old service still runs on port,
-        # so 0 is returned by default. Then, on next run, this recipe is processed
-        # again until a correct value is returned
-        if port != '0':
-          self.options['port'] = port
-          return
+      port = self.getValueFromPreviousRun(name, 'port')
+      # Port can be 0 in case of upgrade: some old service still runs on port,
+      # so 0 is returned by default. Then, on next run, this recipe is processed
+      # again until a correct value is returned
+      if port != '0':
+        self.options['port'] = port
+        return
     except (IOError, ConfigParser.NoSectionError, ConfigParser.NoOptionError):
       pass