Rename `seed` to `shuffle_seed` to better indicate use, and add a test for it.

PiperOrigin-RevId: 287907717
Change-Id: I4f1649ab669058d036a3a076a87024803640eb32

tensorflow/python/data/experimental/kernel_tests/snapshot_test.py

@@ -321,6 +321,41 @@ class SnapshotDatasetTest(reader_dataset_ops_test_base.TFRecordDatasetTestBase,
     dataset3 = dataset3.apply(snapshot.snapshot(tmpdir, shuffle_on_read=True))
     self.assertDatasetProduces(dataset3, expected, assert_items_equal=True)
 
+  @combinations.generate(test_base.default_test_combinations())
+  def testReadShuffledSnapshotWithSeedAfterWrite(self):
+    self.setUpTFRecord(num_files=10, num_records=50)
+    filenames = self.test_filenames
+
+    expected = [
+        b"Record %d of file %d" % (r, f)  # pylint:disable=g-complex-comprehension
+        for f in range(0, 10)
+        for r in range(0, 50)
+    ]
+
+    tmpdir = self.makeSnapshotDirectory()
+    dataset = core_readers._TFRecordDataset(filenames)
+    dataset = dataset.apply(snapshot.snapshot(tmpdir, shard_size_bytes=10))
+    self.assertDatasetProduces(dataset, expected)
+
+    # remove the original files and try to read the data back only from snapshot
+    self.removeTFRecords()
+
+    dataset2 = core_readers._TFRecordDataset(filenames)
+    dataset2 = dataset2.apply(
+        snapshot.snapshot(tmpdir, shuffle_on_read=True, shuffle_seed=123456))
+    next2 = self.getNext(dataset2)
+
+    dataset3 = core_readers._TFRecordDataset(filenames)
+    dataset3 = dataset3.apply(
+        snapshot.snapshot(tmpdir, shuffle_on_read=True, shuffle_seed=123456))
+    next3 = self.getNext(dataset3)
+
+    # make sure that the items are read back in the same order for both datasets
+    for _ in range(500):
+      res2 = self.evaluate(next2())
+      res3 = self.evaluate(next3())
+      self.assertEqual(res2, res3)
+
   @combinations.generate(test_base.default_test_combinations())
   def testReadSnapshotParallelAfterWrite(self):
     self.setUpTFRecord(10, 4000)

tensorflow/python/data/experimental/ops/snapshot.py

@@ -46,7 +46,7 @@ class _SnapshotDataset(dataset_ops.UnaryUnchangedStructureDataset):
                num_writer_threads=None,
                writer_buffer_size=None,
                shuffle_on_read=None,
-               seed=None,
+               shuffle_seed=None,
                mode=None,
                snapshot_name=None):
 
@@ -73,7 +73,7 @@ class _SnapshotDataset(dataset_ops.UnaryUnchangedStructureDataset):
     self._mode = (mode if mode is not None else "auto")
     self._snapshot_name = (snapshot_name if snapshot_name is not None else "")
 
-    self._seed, self._seed2 = random_seed.get_seed(seed)
+    self._seed, self._seed2 = random_seed.get_seed(shuffle_seed)
 
     self._input_dataset = input_dataset
     self._path = ops.convert_to_tensor(path, dtype=dtypes.string, name="path")
@@ -129,7 +129,7 @@ def snapshot(path,
              num_writer_threads=None,
              writer_buffer_size=None,
              shuffle_on_read=None,
-             seed=None,
+             shuffle_seed=None,
              mode=None,
              snapshot_name=None):
   """Writes to/reads from a snapshot of a dataset.
@@ -170,8 +170,10 @@ def snapshot(path,
       buffer before writing them out using `num_writer_threads`.
     shuffle_on_read: If this is True, then the order in which examples are
       produced when reading from a snapshot will be random. Defaults to False.
-    seed: If seed is set, the random number generator is seeded by the given
+    shuffle_seed: Optional. If shuffle_seed is set, the random number generator
-      seed. Otherwise, it is seeded by a random seed.
+      used for shuffling (when shuffle_on_read is turned on) is seeded by the
+      given seed. Otherwise, it is seeded by a random seed that differs for
+      every run.
     mode: The mode at which snapshot should operate. Valid options are "auto",
       "read", "write", and "passthrough". The default mode is "auto", where the
       snapshot op will automatically determine what mode to operate in.
@@ -198,7 +200,7 @@ def snapshot(path,
         num_writer_threads=num_writer_threads,
         writer_buffer_size=writer_buffer_size,
         shuffle_on_read=shuffle_on_read,
-        seed=seed,
+        shuffle_seed=shuffle_seed,
         mode=mode,
         snapshot_name=snapshot_name)