Rework on ParquetDataset for easy access and better cache size in eager mode

tensorflow_io/core/BUILD

@@ -135,6 +135,7 @@ cc_binary(
         "//tensorflow_io/json:json_ops",
         "//tensorflow_io/lmdb:lmdb_ops",
         "//tensorflow_io/mnist:mnist_ops",
+        "//tensorflow_io/parquet:parquet_ops",
         "//tensorflow_io/prometheus:prometheus_ops",
         "//tensorflow_io/text:text_ops",
         "@libarchive",

tensorflow_io/parquet/BUILD

@@ -7,18 +7,16 @@ load(
     "tf_io_copts",
 )
 
-cc_binary(
-    name = "python/ops/_parquet_ops.so",
+cc_library(
+    name = "parquet_ops",
     srcs = [
-        "kernels/parquet_input.cc",
+        "kernels/parquet_kernels.cc",
         "ops/parquet_ops.cc",
     ],
     copts = tf_io_copts(),
-    linkshared = 1,
+    linkstatic = True,
     deps = [
         "//tensorflow_io/core:dataset_ops",
         "@arrow",
-        "@local_config_tf//:libtensorflow_framework",
-        "@local_config_tf//:tf_header_lib",
     ],
 )

tensorflow_io/parquet/__init__.py

@@ -15,18 +15,24 @@
 """Parquet Dataset.
 
 @@ParquetDataset
+@@read_parquet
+@@list_parquet_columns
 """
 
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
 from tensorflow_io.parquet.python.ops.parquet_ops import ParquetDataset
+from tensorflow_io.parquet.python.ops.parquet_ops import read_parquet
+from tensorflow_io.parquet.python.ops.parquet_ops import list_parquet_columns
 
 from tensorflow.python.util.all_util import remove_undocumented
 
 _allowed_symbols = [
     "ParquetDataset",
+    "read_parquet",
+    "list_parquet_columns",
 ]
 
 remove_undocumented(__name__, allowed_exception_list=_allowed_symbols)