plugable: add option to ignore override errors

Add new `no_fail` option to API.add_plugin. When set to True, override
errors are ignored and the affected plugins are skipped.

https://fedorahosted.org/freeipa/ticket/4739

Reviewed-By: David Kupka <dkupka@redhat.com>

1 files changed, 19 insertions, 13 deletions

diff --git a/ipalib/plugable.py b/ipalib/plugable.py
index d55a8f7a4..26fbeaa26 100644
--- a/ipalib/plugable.py
+++ b/ipalib/plugable.py
@@ -638,7 +638,7 @@ class API(ReadOnly):
 
         raise errors.PluginModuleError(name=module.__name__)
 
-    def add_plugin(self, plugin, override=False):
+    def add_plugin(self, plugin, override=False, no_fail=False):
         """
         Add the plugin ``plugin``.
 
@@ -662,23 +662,29 @@ class API(ReadOnly):
         prev = self.__plugins_by_key.get(plugin.full_name)
         if prev:
             if not override:
-                # Must use override=True to override:
-                raise errors.PluginOverrideError(
-                    base=base.__name__,
-                    name=plugin.name,
-                    plugin=plugin,
-                )
+                if no_fail:
+                    return
+                else:
+                    # Must use override=True to override:
+                    raise errors.PluginOverrideError(
+                        base=base.__name__,
+                        name=plugin.name,
+                        plugin=plugin,
+                    )
 
             self.__plugins.remove(prev)
             self.__next[plugin] = prev
         else:
             if override:
-                # There was nothing already registered to override:
-                raise errors.PluginMissingOverrideError(
-                    base=base.__name__,
-                    name=plugin.name,
-                    plugin=plugin,
-                )
+                if no_fail:
+                    return
+                else:
+                    # There was nothing already registered to override:
+                    raise errors.PluginMissingOverrideError(
+                        base=base.__name__,
+                        name=plugin.name,
+                        plugin=plugin,
+                    )
 
         # The plugin is okay, add to sub_d:
         self.__plugins.add(plugin)