Add BagStore.has_bag

1 files changed, 8 insertions, 0 deletions

diff --git a/obnamlib/bag_store.py b/obnamlib/bag_store.py
index e95d385d..abe33baf 100644
--- a/obnamlib/bag_store.py
+++ b/obnamlib/bag_store.py
@@ -52,6 +52,14 @@ class BagStore(object):
         serialised = self._fs.cat(filename)
         return deserialise_bag(serialised)
 
+    def has_bag(self, bag_id):
+        filename = self._make_bag_filename(bag_id)
+        try:
+            st = self._fs.lstat(filename)
+        except (IOError, OSError) as e:  # pragma: no cover
+            return False
+        return st.st_size > 0
+
     def get_bag_ids(self):
         for pathname, st in self._fs.scan_tree(self._dirname):
             if self._is_bag_filename(pathname):