[Dist] Add argument in dispatch_data.py to allow user-defined metadata JSON filename. (#5445)

tools/dispatch_data.py

@@ -37,7 +37,7 @@ def get_launch_cmd(args) -> str:
 
 def submit_jobs(args) -> str:
     # read the json file and get the remaining argument here.
-    schema_path = "metadata.json"
+    schema_path = args.metadata_filename
     with open(os.path.join(args.in_dir, schema_path)) as schema:
         schema_map = json.load(schema)
 
@@ -101,6 +101,12 @@ def main():
         type=str,
         help="Location of the input directory where the dataset is located",
     )
+    parser.add_argument(
+        "--metadata-filename",
+        type=str,
+        default="metadata.json",
+        help="Filename for the metadata JSON file that describes the dataset to be dispatched.",
+    )
     parser.add_argument(
         "--partitions-dir",
         type=str,