CI: Add pre-commit for esp-idf project.

add tools/ci/python_packages/idf_ci.py for some util functions used in
ci and needs multi-os solution

tools/ci/ci_get_mr_info.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python
+#
+# internal use only for CI
+# get latest MR information by source branch
+#
+# Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+#
+# 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.
+#
+
+import argparse
+import os
+import subprocess
+
+from gitlab_api import Gitlab
+
+
+def _get_mr_obj(source_branch):
+    if not source_branch:
+        return None
+    gl = Gitlab(os.getenv('CI_PROJECT_ID', 'espressif/esp-idf'))
+    if not gl.project:
+        return None
+    mrs = gl.project.mergerequests.list(state='opened', source_branch=source_branch)
+    if mrs:
+        return mrs[0]  # one source branch can only have one opened MR at one moment
+    else:
+        return None
+
+
+def get_mr_iid(source_branch):  # type: (str) -> str
+    mr = _get_mr_obj(source_branch)
+    if not mr:
+        return ''
+    else:
+        return str(mr.iid)
+
+
+def get_mr_changed_files(source_branch):
+    mr = _get_mr_obj(source_branch)
+    if not mr:
+        return ''
+
+    return subprocess.check_output(['git', 'diff', '--name-only',
+                                    'origin/{}...origin/{}'.format(mr.target_branch, source_branch)]).decode('utf8')
+
+
+def get_mr_commits(source_branch):
+    mr = _get_mr_obj(source_branch)
+    if not mr:
+        return ''
+    return '\n'.join([commit.id for commit in mr.commits()])
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Get the latest merge request info by pipeline')
+    actions = parser.add_subparsers(dest='action', help='info type')
+
+    common_args = argparse.ArgumentParser(add_help=False)
+    common_args.add_argument('src_branch', nargs='?', help='source branch')
+
+    actions.add_parser('id', parents=[common_args])
+    actions.add_parser('files', parents=[common_args])
+    actions.add_parser('commits', parents=[common_args])
+
+    args = parser.parse_args()
+
+    if args.action == 'id':
+        print(get_mr_iid(args.src_branch))
+    elif args.action == 'files':
+        print(get_mr_changed_files(args.src_branch))
+    elif args.action == 'commits':
+        print(get_mr_commits(args.src_branch))
+    else:
+        raise NotImplementedError('not possible to get here')