[CI] Fix arrow patching and upgrade to v0.5.2.

Author: 2sin18

CONTRIBUTING.md

@@ -0,0 +1,42 @@
+# How to contribute
+
+We appreciate all contributions to improve HybridBackend. You can create an
+[issue](https://github.com/alibaba/HybridBackend/issues) or send a 
+[pull request](https://github.com/alibaba/HybridBackend/pulls).
+
+**Working on your first Pull Request?** You can learn how from this *free* series [How to Contribute to an Open Source Project on GitHub](https://kcd.im/pull-request)
+
+## Code style
+
+Before any commits, please use below tools to format and check code style:
+
+```bash
+cibuild/run cibuild/format
+cibuild/run cibuild/lint
+```
+
+Commit message style should follow below format:
+
+```
+[Module] Do something great.
+```
+
+`Module` could be `CI`, `IO` or other well-known abbreviations.
+
+## Package building
+
+Build code with default developer docker:
+
+```bash
+cibuild/run make -j8
+```
+
+## Unit tests
+
+Test your commit in local node:
+
+```bash
+cibuild/run make test
+```
+
+Also, CI builds would be triggered if a commit is pushed.

README.md

@@ -1,5 +1,7 @@
 # HybridBackend
 
+[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+[![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com)
 [![cibuild: cpu](https://github.com/alibaba/HybridBackend/actions/workflows/cpu-cibuild.yaml/badge.svg?branch=main&event=push)](https://github.com/alibaba/HybridBackend/actions/workflows/cpu-cibuild.yaml)
 [![Documentation Status](https://readthedocs.org/projects/hybridbackend/badge/?version=latest)](https://hybridbackend.readthedocs.io/en/latest/?badge=latest)
 
@@ -36,25 +38,9 @@ pip install -U pip
 
 ## Contributing
 
-We appreciate all contributions to improve HybridBackend. Please follow below
-steps to contribute:
+We appreciate all contributions to improve HybridBackend. Please see
+[Contributing Guide](CONTRIBUTING.md) for more details.
 
-**1. Clone the repository and checkout a new branch.**
+## License
 
-```bash
-git clone <git_repo_addr>
-git pull -r
-git checkout -b features/my_feature
-```
-
-**2. Commit changes, check code style and test.**
-
-```bash
-git commit
-cibuild/run cibuild/format
-cibuild/run cibuild/lint
-cibuild/run make -j8
-cibuild/run make test
-```
-
-**3. Create pull request for code review.**
+HybridBackend is licensed under the [Apache 2.0 License](LICENSE).

arrow/build.sh

@@ -2,7 +2,7 @@
 
 set -eo pipefail
 
-cp -rf arrow/patches/cpp arrow/src/cpp
+cp -rf arrow/patches/cpp arrow/src/
 
 if [[ ! -d $CACHE_DIR ]]; then
   CACHE_DIR=arrow/cache

hybridbackend/__init__.py

@@ -20,6 +20,6 @@
 from __future__ import division
 from __future__ import print_function
 
-__version__ = '0.5.1'
+__version__ = '0.5.2'
 __author__ = 'Alibaba Group Holding Limited'
 __copyright__ = '2021 Alibaba Group Holding Limited'

hybridbackend/tensorflow/training/__init__.py

@@ -0,0 +1,23 @@
+# Copyright 2021 Alibaba Group Holding Limited. All Rights Reserved.
+#
+# 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.
+# =============================================================================
+
+r'''Support for training models in hybridbackend.
+'''
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from hybridbackend.tensorflow.training.step_stat_hook import StepStatHook