Relax run_uuid validation (mlflow#1034)

Allow run IDs to be alphanumeric strings of length 1 to 256, instead of requiring them to be strings of 32 hex chars

mlflow/utils/validation.py

@@ -12,8 +12,8 @@
 
 _VALID_PARAM_AND_METRIC_NAMES = re.compile(r"^[/\w.\- ]*$")
 
-# Regex for valid run IDs: must be a 32-character hex string.
-_RUN_ID_REGEX = re.compile(r"^[0-9a-f]{32}$")
+# Regex for valid run IDs: must be an alphanumeric string of length 1 to 256.
+_RUN_ID_REGEX = re.compile(r"^[a-zA-Z0-9][\w\-]{0,255}$")
 
 _BAD_CHARACTERS_MESSAGE = (
     "Names may only contain alphanumerics, underscores (_), dashes (-), periods (.),"

tests/utils/test_validation.py

@@ -44,9 +44,10 @@ def test_validate_tag_name():
 
 
 def test_validate_run_id():
-    for good_id in ["a" * 32, "f0" * 16, "abcdef0123456789" * 2]:
+    for good_id in ["a" * 32, "f0" * 16, "abcdef0123456789" * 2, "a" * 33, "a" * 31,
+                    "a" * 256, "A" * 32, "g" * 32, "a_" * 32, "abcdefghijklmnopqrstuvqxyz"]:
         _validate_run_id(good_id)
-    for bad_id in ["a" * 33, "a" * 31, "A" * 32, "g" * 32, "a/bc" * 8, "_" * 32]:
+    for bad_id in ["a/bc" * 8, "", "a" * 400, "*" * 5]:
         with pytest.raises(MlflowException, match="Invalid run ID") as e:
             _validate_run_id(bad_id)
         assert e.value.error_code == ErrorCode.Name(INVALID_PARAMETER_VALUE)