Only generate model uuid when logging model

mlflow/models/model.py

@@ -6,7 +6,7 @@
 import os
 import uuid
 
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Optional, Union, Callable
 
 import mlflow
 from mlflow.exceptions import MlflowException
@@ -42,7 +42,7 @@ def __init__(
         flavors=None,
         signature=None,  # ModelSignature
         saved_input_example_info: Dict[str, Any] = None,
-        model_uuid=None,
+        model_uuid: Union[str, Callable, None] = lambda: uuid.uuid4().hex,
         **kwargs,
     ):
         # store model id instead of run_id and path to avoid confusion when model gets exported
@@ -54,7 +54,7 @@ def __init__(
         self.flavors = flavors if flavors is not None else {}
         self.signature = signature
         self.saved_input_example_info = saved_input_example_info
-        self.model_uuid = uuid.uuid4().hex if model_uuid is None else model_uuid
+        self.model_uuid = model_uuid() if callable(model_uuid) else model_uuid
         self.__dict__.update(kwargs)
 
     def __eq__(self, other):
@@ -133,10 +133,13 @@ def from_dict(cls, model_dict):
 
         from .signature import ModelSignature
 
+        model_dict = model_dict.copy()
         if "signature" in model_dict and isinstance(model_dict["signature"], dict):
-            model_dict = model_dict.copy()
             model_dict["signature"] = ModelSignature.from_dict(model_dict["signature"])
 
+        if "model_uuid" not in model_dict:
+            model_dict["model_uuid"] = None
+
         return cls(**model_dict)
 
     @classmethod

tests/models/test_model.py

@@ -164,3 +164,31 @@ def test_model_log_with_input_example_succeeds():
         # date column will get deserialized into string
         input_example["d"] = input_example["d"].apply(lambda x: x.isoformat())
         assert x.equals(input_example)
+
+
+def _is_valid_uuid(val):
+    import uuid
+
+    try:
+        uuid.UUID(str(val))
+        return True
+    except ValueError:
+        return False
+
+
+def test_model_uuid():
+    m = Model()
+    assert m.model_uuid is not None
+    assert _is_valid_uuid(m.model_uuid)
+
+    m2 = Model()
+    assert m.model_uuid != m2.model_uuid
+
+    m_dict = m.to_dict()
+    assert m_dict["model_uuid"] == m.model_uuid
+    m3 = Model.from_dict(m_dict)
+    assert m3.model_uuid == m.model_uuid
+
+    m_dict.pop("model_uuid")
+    m4 = Model.from_dict(m_dict)
+    assert m4.model_uuid is None

tests/pyfunc/test_model_export_with_loader_module_and_data_path.py

@@ -556,26 +556,6 @@ def test_column_schema_enforcement_no_col_names():
     assert pyfunc_model.predict(d).equals(pd.DataFrame(d))
 
 
-def _is_valid_uuid(val):
-    import uuid
-
-    try:
-        uuid.UUID(str(val))
-        return True
-    except ValueError:
-        return False
-
-
-def test_model_uuid():
-    m = Model()
-    assert m.model_uuid is not None
-    assert _is_valid_uuid(m.model_uuid)
-    m_dict = m.to_dict()
-    assert m_dict["model_uuid"] == m.model_uuid
-    m2 = Model.from_dict(m_dict)
-    assert m2.model_uuid == m.model_uuid
-
-
 def test_tensor_schema_enforcement_no_col_names():
     m = Model()
     input_schema = Schema([TensorSpec(np.dtype(np.float32), (-1, 3))])