Expose tf.contrib.checkpoint.PythonStateWrapper.

This makes it possible to checkpoint arbitrary python state if it can be
serialized to a string.

Also updates NumpyState to accept np.int32, np.int64, np.float32, np.float64
types.

PiperOrigin-RevId: 212879609

3 files changed, 35 insertions, 12 deletions

diff --git a/tensorflow/contrib/checkpoint/__init__.py b/tensorflow/contrib/checkpoint/__init__.py
index 150d734db6..94b7f4f867 100644
--- a/tensorflow/contrib/checkpoint/__init__.py
+++ b/tensorflow/contrib/checkpoint/__init__.py
@@ -37,6 +37,7 @@ Checkpoint management:
 
 Saving and restoring Python state:
 @@NumpyState
+@@PythonStateWrapper
 """
 
 from __future__ import absolute_import
@@ -45,6 +46,7 @@ from __future__ import print_function
 
 from tensorflow.contrib.checkpoint.python.containers import UniqueNameTracker
 from tensorflow.contrib.checkpoint.python.python_state import NumpyState
+from tensorflow.contrib.checkpoint.python.python_state import PythonStateWrapper
 from tensorflow.contrib.checkpoint.python.split_dependency import split_dependency
 from tensorflow.contrib.checkpoint.python.visualize import dot_graph_from_checkpoint
 from tensorflow.core.protobuf.checkpointable_object_graph_pb2 import CheckpointableObjectGraph
diff --git a/tensorflow/contrib/checkpoint/python/python_state.py b/tensorflow/contrib/checkpoint/python/python_state.py
index 9b11035b6d..302d5cfb79 100644
--- a/tensorflow/contrib/checkpoint/python/python_state.py
+++ b/tensorflow/contrib/checkpoint/python/python_state.py
@@ -17,7 +17,9 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import abc
 import functools
+import six
 
 import numpy
 
@@ -101,7 +103,7 @@ class NumpyState(base.CheckpointableBase):
     # TODO(allenl): Consider supporting lists/tuples, either ad-hoc or by making
     # ndarrays checkpointable natively and using standard checkpointable list
     # tracking.
-    if isinstance(value, numpy.ndarray):
+    if isinstance(value, (numpy.ndarray, numpy.generic)):
       try:
         existing = super(NumpyState, self).__getattribute__(name)
         existing.array = value
@@ -127,7 +129,29 @@ class NumpyState(base.CheckpointableBase):
     super(NumpyState, self).__setattr__(name, value)
 
 
-class _NumpyWrapper(base.CheckpointableBase):
+@six.add_metaclass(abc.ABCMeta)
+class PythonStateWrapper(base.CheckpointableBase):
+  """Wraps a Python object for storage in an object-based checkpoint."""
+
+  @abc.abstractmethod
+  def _serialize(self):
+    """Callback for `PythonStringStateSaveable` to serialize the object."""
+
+  @abc.abstractmethod
+  def _deserialize(self, string_value):
+    """Callback for `PythonStringStateSaveable` to deserialize the object."""
+
+  def _gather_saveables_for_checkpoint(self):
+    """Specify callbacks for saving and restoring `array`."""
+    return {
+        "py_state": functools.partial(
+            base.PythonStringStateSaveable,
+            state_callback=self._serialize,
+            restore_callback=self._deserialize)
+        }
+
+
+class _NumpyWrapper(PythonStateWrapper):
   """Wraps a NumPy array for storage in an object-based checkpoint."""
 
   def __init__(self, array):
@@ -139,7 +163,7 @@ class _NumpyWrapper(base.CheckpointableBase):
     self.array = array
 
   def _serialize(self):
-    """Callback for `PythonStringStateSaveable` to serialize the array."""
+    """Callback to serialize the array."""
     string_file = BytesIO()
     try:
       numpy.save(string_file, self.array, allow_pickle=False)
@@ -149,18 +173,10 @@ class _NumpyWrapper(base.CheckpointableBase):
     return serialized
 
   def _deserialize(self, string_value):
-    """Callback for `PythonStringStateSaveable` to deserialize the array."""
+    """Callback to deserialize the array."""
     string_file = BytesIO(string_value)
     try:
       self.array = numpy.load(string_file, allow_pickle=False)
     finally:
       string_file.close()
 
-  def _gather_saveables_for_checkpoint(self):
-    """Specify callbacks for saving and restoring `array`."""
-    return {
-        "array": functools.partial(
-            base.PythonStringStateSaveable,
-            state_callback=self._serialize,
-            restore_callback=self._deserialize)
-        }
diff --git a/tensorflow/contrib/checkpoint/python/python_state_test.py b/tensorflow/contrib/checkpoint/python/python_state_test.py
index 0439a4755e..45494351ff 100644
--- a/tensorflow/contrib/checkpoint/python/python_state_test.py
+++ b/tensorflow/contrib/checkpoint/python/python_state_test.py
@@ -40,10 +40,13 @@ class NumpyStateTests(test.TestCase):
     save_state.a = numpy.ones([2, 2])
     save_state.b = numpy.ones([2, 2])
     save_state.b = numpy.zeros([2, 2])
+    save_state.c = numpy.int64(3)
     self.assertAllEqual(numpy.ones([2, 2]), save_state.a)
     self.assertAllEqual(numpy.zeros([2, 2]), save_state.b)
+    self.assertEqual(3, save_state.c)
     first_save_path = saver.save(prefix)
     save_state.a[1, 1] = 2.
+    save_state.c = numpy.int64(4)
     second_save_path = saver.save(prefix)
 
     load_state = python_state.NumpyState()
@@ -51,6 +54,7 @@ class NumpyStateTests(test.TestCase):
     loader.restore(first_save_path).initialize_or_restore()
     self.assertAllEqual(numpy.ones([2, 2]), load_state.a)
     self.assertAllEqual(numpy.zeros([2, 2]), load_state.b)
+    self.assertEqual(3, load_state.c)
     load_state.a[0, 0] = 42.
     self.assertAllEqual([[42., 1.], [1., 1.]], load_state.a)
     loader.restore(first_save_path).run_restore_ops()
@@ -58,6 +62,7 @@ class NumpyStateTests(test.TestCase):
     loader.restore(second_save_path).run_restore_ops()
     self.assertAllEqual([[1., 1.], [1., 2.]], load_state.a)
     self.assertAllEqual(numpy.zeros([2, 2]), load_state.b)
+    self.assertEqual(4, load_state.c)
 
   def testNoGraphPollution(self):
     graph = ops.Graph()