scripts: add make_bugs_pickle.py

This is a simple script which snapshots open bugs in the
zephyrproject-rtos/zephyr repository using the GitHub REST API.

It relies on the 'github' module, which is a de-facto standard for
accessing this API in Python:

  https://pygithub.readthedocs.io

We are already using this package in scripts/release/bug_bash.py, so
this is not a new dependency, even though it's a third party package
not available in the standard library.

The resulting bugs are stored in the standard library's 'pickle'
format, as a list of github.Issue.Issue objects. For more on pickle,
see:

  https://docs.python.org/3/library/pickle.html

I am choosing pickle because it is standard, easy to use, and we are
already using it in the build system to store the edtlib.EDT object
created by gen_defines.py. This is also therefore not a new
dependency (and even if it were, it's in the standard library).

Signed-off-by: Martí Bolívar <[email protected]>

scripts/make_bugs_pickle.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2022 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# stdlib
+import argparse
+import pickle
+import sys
+from pathlib import Path
+from typing import BinaryIO, List
+
+# third party
+from github.Issue import Issue
+
+# other zephyr/scripts modules
+from github_helpers import get_github_object
+
+# Note that type annotations are not currently statically checked, and
+# should only be considered documentation.
+
+def parse_args() -> argparse.Namespace:
+    '''Parse command line arguments.'''
+    parser = argparse.ArgumentParser(
+        description='''
+A helper script which loads all open bugs in the
+zephyrproject-rtos/zephyr repository using the GitHub API, and writes
+them to a new pickle file as a list of github.Issue.Issue objects.
+
+For more information, see:
+
+  - GitHub API: https://docs.github.com/en/rest
+  - github.Issue.Issue:
+    https://pygithub.readthedocs.io/en/latest/github_objects/Issue.html
+  - pickle: https://docs.python.org/3/library/pickle.html
+''',
+        formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument('out_file', metavar='OUTFILE', type=Path, nargs='?',
+                        help='''file to write pickle data to (default:
+                        stdout)''')
+    return parser.parse_args()
+
+def get_open_bugs() -> List[Issue]:
+    zephyr_repo = get_github_object().get_repo('zephyrproject-rtos/zephyr')
+    return list(zephyr_repo.get_issues(state='open', labels=['bug']))
+
+def open_out_file(args: argparse.Namespace) -> BinaryIO:
+    if args.out_file is None:
+        return open(sys.stdout.fileno(), 'wb', closefd=False)
+
+    return open(args.out_file, 'wb')
+
+def main() -> None:
+    args = parse_args()
+    open_bugs = get_open_bugs()
+
+    with open_out_file(args) as out_file:
+        pickle.dump(open_bugs, out_file)
+
+if __name__ == '__main__':
+    main()