Always detect Ray Dataset as distributed (#253)

Ensures that we always use distributed loading by default with Ray Datasets. Followup to ray-project/ray#31079

Signed-off-by: Antoni Baum <[email protected]>

xgboost_ray/matrix.py

@@ -24,7 +24,7 @@
 
 try:
     from ray.data.dataset import Dataset as RayDataset
-except (ImportError, ModuleNotFoundError):
+except ImportError:
 
     class RayDataset:
         pass
@@ -916,6 +916,8 @@ def _can_load_distributed(source: Data) -> bool:
         return False
     elif Modin.is_data_type(source):
         return True
+    elif isinstance(source, RayDataset):
+        return True
     elif isinstance(source, str):
         # Strings should point to files or URLs
         # Usually parquet files point to directories
@@ -940,6 +942,8 @@ def _detect_distributed(source: Data) -> bool:
         return False
     if Modin.is_data_type(source):
         return True
+    if isinstance(source, RayDataset):
+        return True
     if isinstance(source, Iterable) and not isinstance(source, str) and \
        not (isinstance(source, Sequence) and isinstance(source[0], str)):
         # This is an iterable but not a Sequence of strings, and not a

xgboost_ray/tests/test_matrix.py

@@ -8,6 +8,11 @@
 import pandas as pd
 
 import ray
+try:
+    import ray.data as ray_data
+except (ImportError, ModuleNotFoundError):
+
+    ray_data = None
 
 from xgboost_ray import RayDMatrix
 from xgboost_ray.matrix import (concat_dataframes, RayShardingMode,
@@ -29,7 +34,7 @@ def setUp(self):
 
     @classmethod
     def setUpClass(cls):
-        ray.init(local_mode=True)
+        ray.init()
 
     @classmethod
     def tearDownClass(cls):
@@ -315,6 +320,11 @@ def testDetectDistributed(self):
             mat = RayDMatrix([csv_file] * 3, lazy=True)
             self.assertTrue(mat.distributed)
 
+            if ray_data:
+                ds = ray_data.read_parquet(parquet_file)
+                mat = RayDMatrix(ds)
+                self.assertTrue(mat.distributed)
+
     def testTooManyActorsDistributed(self):
         """Test error when too many actors are passed"""
         with self.assertRaises(RuntimeError):