addons may provide a list of ifupdown scripts to ignore

Ticket:
Reviewed By: Roopa, Nikhil G
Testing Done:

ifupdown2's python addons are replacing some/most of the old ifupdown shell
scripts. When addon_scripts_support is set to 1, ifupdown2 will execute every
scripts present in /etc/network/if-$ACTION.d/ if a script exists with a name
identical to an ifupdown2 addon, this script won't be executed.

Sometimes an ifupdown2 addons doesn't have the same name as the ifupdown script
it's supposed to replace. Or maybe one addon is replacing several scripts.
For example: bond.py is replacing /etc/network/if-*.d/ifenslave

Now each addon is able to provide a list of script to ignore.

[16:54:40] root:ifupdown2 # ifquery bond0
iface bond0
      bond-slaves tap0 tap1

[16:54:49] root:ifupdown2 # ifreload -a -d &> /tmp/ifreload.log
[16:54:54] root:ifupdown2 # cat /tmp/ifreload.log | grep ifenslave
debug: tap1: pre-up : running script /etc/network/if-pre-up.d/ifenslave
info: executing /etc/network/if-pre-up.d/ifenslave
debug: tap1: up : running script /etc/network/if-up.d/ifenslave
info: executing /etc/network/if-up.d/ifenslave
debug: lo: pre-up : running script /etc/network/if-pre-up.d/ifenslave
info: executing /etc/network/if-pre-up.d/ifenslave
debug: lo: up : running script /etc/network/if-up.d/ifenslave
info: executing /etc/network/if-up.d/ifenslave
debug: eth0: pre-up : running script /etc/network/if-pre-up.d/ifenslave
info: executing /etc/network/if-pre-up.d/ifenslave
debug: eth0: up : running script /etc/network/if-up.d/ifenslave
info: executing /etc/network/if-up.d/ifenslave
debug: tap0: pre-up : running script /etc/network/if-pre-up.d/ifenslave
info: executing /etc/network/if-pre-up.d/ifenslave
debug: tap0: up : running script /etc/network/if-up.d/ifenslave
info: executing /etc/network/if-up.d/ifenslave
[16:54:55] root:ifupdown2 #
...
apply patch
...
[16:55:16] root:ifupdown2 # ifreload -a -d &> /tmp/ifreload.log
[16:55:18] root:ifupdown2 # cat /tmp/ifreload.log | grep ifenslave
[16:55:19] root:ifupdown2 #

Signed-off-by: Julien Fortin <julien@cumulusnetworks.com>

addons/bond.py

@@ -17,6 +17,9 @@ from ifupdown.utils import utils
 
 class bond(moduleBase):
     """  ifupdown2 addon module to configure bond interfaces """
+
+    overrides_ifupdown_scripts = ['ifenslave', ]
+
     _modinfo = { 'mhelp' : 'bond configuration module',
                     'attrs' : {
                     'bond-use-carrier':

ifupdown/ifupdownmain.py

@@ -222,7 +222,8 @@ class ifupdownMain(ifupdownBase):
         self.pp = pprint.PrettyPrinter(indent=4)
         self.modules = OrderedDict({})
         self.module_attrs = {}
-      
+        self.overridden_ifupdown_scripts = []
+
         if self.config.get('addon_python_modules_support', '1') == '1':
             self.load_addon_modules(self.addon_modules_dir)
         if self.config.get('addon_scripts_support', '0') == '1':
@@ -1198,10 +1199,11 @@ class ifupdownMain(ifupdownBase):
                             raise
                         try:
                             minstance = mclass()
+                            script_override = minstance.get_overrides_ifupdown_scripts()
+                            self.overridden_ifupdown_scripts.extend(script_override)
                         except moduleNotSupported, e:
                             self.logger.info('module %s not loaded (%s)\n'
                                              %(mname, str(e)))
-                            pass
                             continue
                         except:
                             raise
@@ -1281,10 +1283,9 @@ class ifupdownMain(ifupdownBase):
             try:
                 module_list = os.listdir(msubdir)
                 for module in module_list:
-                    if  self.modules.get(module) is not None:
+                    if self.modules.get(module) or module in self.overridden_ifupdown_scripts:
                         continue
-                    self.script_ops[op].append(
+                    self.script_ops[op].append(msubdir + '/' + module)
-                                    msubdir + '/' + module)
             except: 
                 # continue reading
                 pass

ifupdownaddons/modulebase.py

@@ -333,6 +333,13 @@ class moduleBase(object):
         except:
             return None
 
+    def get_overrides_ifupdown_scripts(self):
+        """ return the ifupdown scripts replaced by the current module """
+        try:
+            return self.overrides_ifupdown_scripts
+        except:
+            return []
+
     def _get_reserved_vlan_range(self):
         start = end = 0
         get_resvvlan = '/var/lib/ifupdown2/hooks/get_reserved_vlan_range.sh'