Persisted incremental data: add a global_cache for DataBags and DataSlices.

PiperOrigin-RevId: 871821248
Change-Id: I138c1a9d7199598b4bf9037d28307bca188f77a0

Author: svsgoogle

py/koladata/ext/persisted_data/BUILD

@@ -448,6 +448,30 @@ py_library(
     deps = ["//py:python_path"],
 )
 
+py_library(
+    name = "global_cache_lib",
+    srcs = ["global_cache_lib.py"],
+    deps = [
+        ":lru_size_tracking_cache",
+        "//py:python_path",
+        "//py/koladata:kd",
+        "@com_google_absl_py//absl/flags",
+    ],
+)
+
+py_test(
+    name = "global_cache_lib_test",
+    srcs = ["global_cache_lib_test.py"],
+    deps = [
+        ":global_cache_lib",
+        ":lru_size_tracking_cache",
+        "//py:python_path",
+        "@com_google_absl_py//absl/flags",
+        "@com_google_absl_py//absl/testing:absltest",
+        "@com_google_absl_py//absl/testing:flagsaver",
+    ],
+)
+
 py_test(
     name = "lru_size_tracking_cache_test",
     srcs = ["lru_size_tracking_cache_test.py"],

py/koladata/ext/persisted_data/global_cache_lib.py

@@ -0,0 +1,62 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Global cache for persisted incremental data."""
+
+from absl import flags
+from koladata import kd
+from koladata.ext.persisted_data import lru_size_tracking_cache as _lru_size_tracking_cache
+
+_DEFAULT_MAX_SIZE_MB = 1024 * 10  # 10 GiB
+_mb_to_bytes = lambda mb: mb * 1024 * 1024
+
+KD_EXT_PERSISTED_DATA_GLOBAL_CACHE_MAX_SIZE_MB = flags.DEFINE_integer(
+    'kd_ext_persisted_data_global_cache_max_size_mb',
+    _DEFAULT_MAX_SIZE_MB,
+    'The maximum size of the kd_ext.persisted_data global cache in megabytes.',
+)
+
+
+def _kd_ext_persisted_data_global_cache_max_size_mb_validator(
+    value: int,
+) -> bool:
+  if value < 0:
+    return False
+  get_global_cache().set_max_total_bytes_of_entries_in_cache(
+      _mb_to_bytes(value)
+  )
+  return True
+
+
+flags.register_validator(
+    'kd_ext_persisted_data_global_cache_max_size_mb',
+    _kd_ext_persisted_data_global_cache_max_size_mb_validator,
+    message='Must be a non-negative number.',
+    flag_values=flags.FLAGS,
+)
+
+
+CACHE_VALUE_TYPE = kd.types.DataBag | kd.types.DataSlice
+
+Cache = _lru_size_tracking_cache.LruSizeTrackingCache
+CacheEntryMetadata = _lru_size_tracking_cache.CacheEntryMetadata
+
+_CACHE: Cache[str, CACHE_VALUE_TYPE] = Cache(
+    max_total_bytes_of_entries_in_cache=_mb_to_bytes(_DEFAULT_MAX_SIZE_MB)
+)
+
+
+def get_global_cache() -> Cache[str, CACHE_VALUE_TYPE]:
+  """Returns the global cache."""
+  return _CACHE

py/koladata/ext/persisted_data/global_cache_lib_test.py

@@ -0,0 +1,61 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from absl import flags
+from absl.testing import absltest
+from absl.testing import flagsaver
+from koladata.ext.persisted_data import global_cache_lib
+from koladata.ext.persisted_data import lru_size_tracking_cache
+
+
+class GlobalCacheLibTest(absltest.TestCase):
+
+  def test_get_global_cache_return_type(self):
+    cache = global_cache_lib.get_global_cache()
+    self.assertIsInstance(cache, lru_size_tracking_cache.LruSizeTrackingCache)
+
+  def test_get_global_cache_repeated_calls_return_same_object(self):
+    result1 = global_cache_lib.get_global_cache()
+    result2 = global_cache_lib.get_global_cache()
+
+    self.assertIs(result1, result2)
+
+  def test_global_cache_default_max_size(self):
+    self.assertEqual(
+        global_cache_lib.get_global_cache().get_max_total_bytes_of_entries_in_cache(),
+        global_cache_lib._DEFAULT_MAX_SIZE_MB * 1024 * 1024,
+    )
+
+  @flagsaver.flagsaver()
+  def test_kd_ext_persisted_data_global_cache_max_size_mb_flag_validation(self):
+    with self.assertRaises(flags._exceptions.IllegalFlagValueError):
+      flags.FLAGS.kd_ext_persisted_data_global_cache_max_size_mb = -1
+
+  @flagsaver.flagsaver()
+  def test_kd_ext_persisted_data_global_cache_max_size_mb_flag_updates_cache(
+      self,
+  ):
+    self.assertNotEqual(
+        global_cache_lib.get_global_cache().get_max_total_bytes_of_entries_in_cache(),
+        42 * 1024 * 1024,
+    )
+    flags.FLAGS.kd_ext_persisted_data_global_cache_max_size_mb = 42
+    self.assertEqual(
+        global_cache_lib.get_global_cache().get_max_total_bytes_of_entries_in_cache(),
+        42 * 1024 * 1024,
+    )
+
+
+if __name__ == '__main__':
+  absltest.main()