Adds ability to write to json file

fractal/cli/utils.py

@@ -1,3 +1,4 @@
+import json
 import os
 import re
 from getpass import getpass
@@ -14,21 +15,26 @@ class InvalidMatrixIdException(Exception):
     pass
 
 
-def write_user_data(data: Dict[str, Any], filename: str) -> None:
+def write_user_data(data: Dict[str, Any], filename: str, format: str = "yaml") -> str:
     """
     Write data to yaml file <filename> in user's appdir (ie ~/.local/share/fractal)
     """
     makedirs(data_dir, exist_ok=True)
 
-    try:
-        data_to_write = yaml.dump(data)
-    except yaml.YAMLError as error:
-        raise error
+    match format:
+        case "yaml":
+            data_to_write = yaml.dump(data)
+        case "json":
+            data_to_write = json.dumps(data)
+        case _:
+            raise ValueError(f"Invalid format: {format}")
 
-    user_data = os.path.join(data_dir, filename)
-    with open(user_data, "w") as file:
+    data_file = os.path.join(data_dir, filename)
+    with open(data_file, "w") as file:
         file.write(data_to_write)
 
+    return data_file
+
 
 def read_user_data(filename: str) -> Tuple[Dict[str, Any], str]:
     """