Support changing gitignore from event handler API

lib/tfw/components/directory_snapshotting_event_handler.py

@@ -17,20 +17,26 @@ LOG = logging.getLogger(__name__)
 
 
 class DirectorySnapshottingEventHandler(EventHandlerBase):
-    def __init__(self, key, directories):
+    def __init__(self, key, directories, exclude_unix_patterns=None):
         super().__init__(key)
         self.snapshot_providers = {}
+        self._exclude_unix_patterns = exclude_unix_patterns
         self.init_snapshot_providers(directories)
 
         self.command_handlers = {
             'take_snapshot': self.handle_take_snapshot,
-            'restore_snapshot': self.handle_restore_snapshot
+            'restore_snapshot': self.handle_restore_snapshot,
+            'exclude': self.handle_exclude
         }
 
     def init_snapshot_providers(self, directories):
         for index, directory in enumerate(directories):
             git_dir = self.init_git_dir(index, directory)
-            self.snapshot_providers[directory] = SnapshotProvider(directory, git_dir)
+            self.snapshot_providers[directory] = SnapshotProvider(
+                directory,
+                git_dir,
+                self._exclude_unix_patterns
+            )
 
     @staticmethod
     def init_git_dir(index, directory):
@@ -70,3 +76,12 @@ class DirectorySnapshottingEventHandler(EventHandlerBase):
         for provider in self.snapshot_providers.values():
             provider.restore_snapshot(date)
         return data
+
+    def handle_exclude(self, data):
+        exclude_unix_patterns = data['value']
+        if not isinstance(exclude_unix_patterns, list):
+            raise KeyError
+
+        for provider in self.snapshot_providers.values():
+            provider.exclude = exclude_unix_patterns
+        return data