get/get_many: add raise_missing=True param

src/borg/legacyrepository.py

@@ -1211,18 +1211,21 @@ def list(self, limit=None, marker=None):
             self.index = self.open_index(self.get_transaction_id())
         return [id_ for id_, _ in islice(self.index.iteritems(marker=marker), limit)]
 
-    def get(self, id, read_data=True):
+    def get(self, id, read_data=True, raise_missing=True):
         if not self.index:
             self.index = self.open_index(self.get_transaction_id())
         try:
             in_index = NSIndex1Entry(*(self.index[id][:2]))  # legacy: index entries have no size element
             return self.io.read(in_index.segment, in_index.offset, id, read_data=read_data)
         except KeyError:
-            raise self.ObjectNotFound(id, self.path) from None
+            if raise_missing:
+                raise self.ObjectNotFound(id, self.path) from None
+            else:
+                return None
 
-    def get_many(self, ids, read_data=True, is_preloaded=False):
+    def get_many(self, ids, read_data=True, is_preloaded=False, raise_missing=True):
         for id_ in ids:
-            yield self.get(id_, read_data=read_data)
+            yield self.get(id_, read_data=read_data, raise_missing=raise_missing)
 
     def put(self, id, data, wait=True):
         """put a repo object

src/borg/remote.py

@@ -965,7 +965,7 @@ def handle_error(unpacked):
                             self.to_send.push_back(msgpack.packb({MSGID: self.msgid, MSG: cmd, ARGS: args}))
                     if not self.to_send and self.preload_ids:
                         chunk_id = self.preload_ids.pop(0)
-                        args = {"id": chunk_id}
+                        args = {"id": chunk_id, "raise_missing": True}
                         self.msgid += 1
                         self.chunkid_to_msgids.setdefault(chunk_id, []).append(self.msgid)
                         self.to_send.push_back(msgpack.packb({MSGID: self.msgid, MSG: "get", ARGS: args}))
@@ -1024,12 +1024,16 @@ def __len__(self):
     def list(self, limit=None, marker=None):
         """actual remoting is done via self.call in the @api decorator"""
 
-    def get(self, id, read_data=True):
-        for resp in self.get_many([id], read_data=read_data):
+    def get(self, id, read_data=True, raise_missing=True):
+        for resp in self.get_many([id], read_data=read_data, raise_missing=raise_missing):
             return resp
 
-    def get_many(self, ids, read_data=True, is_preloaded=False):
-        yield from self.call_many("get", [{"id": id, "read_data": read_data} for id in ids], is_preloaded=is_preloaded)
+    def get_many(self, ids, read_data=True, is_preloaded=False, raise_missing=True):
+        yield from self.call_many(
+            "get",
+            [{"id": id, "read_data": read_data, "raise_missing": raise_missing} for id in ids],
+            is_preloaded=is_preloaded,
+        )
 
     @api(since=parse_version("1.0.0"))
     def put(self, id, data, wait=True):
@@ -1131,11 +1135,11 @@ def __enter__(self):
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.close()
 
-    def get(self, key, read_data=True):
-        return next(self.get_many([key], read_data=read_data, cache=False))
+    def get(self, key, read_data=True, raise_missing=True):
+        return next(self.get_many([key], read_data=read_data, raise_missing=raise_missing, cache=False))
 
-    def get_many(self, keys, read_data=True, cache=True):
-        for key, data in zip(keys, self.repository.get_many(keys, read_data=read_data)):
+    def get_many(self, keys, read_data=True, raise_missing=True, cache=True):
+        for key, data in zip(keys, self.repository.get_many(keys, read_data=read_data, raise_missing=raise_missing)):
             yield self.transform(key, data)
 
     def log_instrumentation(self):
@@ -1240,10 +1244,12 @@ def close(self):
         self.cache.clear()
         shutil.rmtree(self.basedir)
 
-    def get_many(self, keys, read_data=True, cache=True):
+    def get_many(self, keys, read_data=True, raise_missing=True, cache=True):
         # It could use different cache keys depending on read_data and cache full vs. meta-only chunks.
         unknown_keys = [key for key in keys if self.prefixed_key(key, complete=read_data) not in self.cache]
-        repository_iterator = zip(unknown_keys, self.repository.get_many(unknown_keys, read_data=read_data))
+        repository_iterator = zip(
+            unknown_keys, self.repository.get_many(unknown_keys, read_data=read_data, raise_missing=raise_missing)
+        )
         for key in keys:
             pkey = self.prefixed_key(key, complete=read_data)
             if pkey in self.cache:
@@ -1261,7 +1267,7 @@ def get_many(self, keys, read_data=True, cache=True):
                 else:
                     # slow path: eviction during this get_many removed this key from the cache
                     t0 = time.perf_counter()
-                    data = self.repository.get(key, read_data=read_data)
+                    data = self.repository.get(key, read_data=read_data, raise_missing=raise_missing)
                     self.slow_lat += time.perf_counter() - t0
                     transformed = self.add_entry(key, data, cache, complete=read_data)
                     self.slow_misses += 1

src/borg/repository.py

@@ -426,7 +426,7 @@ def list(self, limit=None, marker=None):
                     # note: do not collect the marker id
         return result
 
-    def get(self, id, read_data=True):
+    def get(self, id, read_data=True, raise_missing=True):
         self._lock_refresh()
         id_hex = bin_to_hex(id)
         key = "data/" + id_hex
@@ -453,11 +453,14 @@ def get(self, id, read_data=True):
                     raise IntegrityError(f"Object too small [id {id_hex}]: expected {meta_size}, got {len(meta)} bytes")
                 return hdr + meta
         except StoreObjectNotFound:
-            raise self.ObjectNotFound(id, str(self._location)) from None
+            if raise_missing:
+                raise self.ObjectNotFound(id, str(self._location)) from None
+            else:
+                return None
 
-    def get_many(self, ids, read_data=True, is_preloaded=False):
+    def get_many(self, ids, read_data=True, is_preloaded=False, raise_missing=True):
         for id_ in ids:
-            yield self.get(id_, read_data=read_data)
+            yield self.get(id_, read_data=read_data, raise_missing=raise_missing)
 
     def put(self, id, data, wait=True):
         """put a repo object