Add functionality to load scheduler cfg from a json string

torchx/specs/api.py

@@ -913,6 +913,23 @@ def _cast_to_type(value: str, opt_type: Type[CfgVal]) -> CfgVal:
                 cfg[key] = _cast_to_type(val, runopt_.opt_type)
         return cfg
 
+    def cfg_from_json_repr(self, json_repr: str) -> Dict[str, CfgVal]:
+        """
+        Converts the given dict to a valid cfg for this ``runopts`` object.
+        """
+        cfg: Dict[str, CfgVal] = {}
+        cfg_dict = json.loads(json_repr)
+        for key, val in cfg_dict.items():
+            runopt_ = self.get(key)
+            if runopt_:
+                if runopt_.opt_type == List[str]:
+                    cfg[key] = [str(v) for v in val]
+                elif runopt_.opt_type == Dict[str, str]:
+                    cfg[key] = {str(k): str(v) for k, v in val.items()}
+                else:
+                    cfg[key] = val
+        return cfg
+
     def add(
         self,
         cfg_key: str,

torchx/specs/test/api_test.py

@@ -485,6 +485,41 @@ def test_resolve_from_str(self) -> None:
             ),
         ),
 
+    def test_config_from_json_repr(self) -> None:
+        opts = runopts()
+        opts.add("foo", type_=str, default="", help="")
+        opts.add("test_key", type_=str, default="", help="")
+        opts.add("default_time", type_=int, default=0, help="")
+        opts.add("enable", type_=bool, default=True, help="")
+        opts.add("disable", type_=bool, default=True, help="")
+        opts.add("complex_list", type_=List[str], default=[], help="")
+        opts.add("complex_dict", type_=Dict[str, str], default={}, help="")
+
+        self.assertDictEqual(
+            {
+                "foo": "bar",
+                "test_key": "test_value",
+                "default_time": 42,
+                "enable": True,
+                "disable": False,
+                "complex_list": ["v1", "v2", "v3"],
+                "complex_dict": {"k1": "v1", "k2": "v2"},
+            },
+            opts.resolve(
+                opts.cfg_from_json_repr(
+                    """{
+                        "foo": "bar",
+                        "test_key": "test_value",
+                        "default_time": 42,
+                        "enable": true,
+                        "disable": false,
+                        "complex_list": ["v1", "v2", "v3"],
+                        "complex_dict": {"k1": "v1", "k2": "v2"}
+                    }"""
+                )
+            ),
+        )
+
     def test_runopts_is_type(self) -> None:
         # primitive types
         self.assertTrue(runopts.is_type(3, int))