1# Copyright 2017, Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15"""Private helpers for futures."""
16
17import logging
18import threading
19
20
21_LOGGER = logging.getLogger(__name__)
22
23
24def start_daemon_thread(*args, **kwargs):
25    """Starts a thread and marks it as a daemon thread."""
26    thread = threading.Thread(*args, **kwargs)
27    thread.daemon = True
28    thread.start()
29    return thread
30
31
32def safe_invoke_callback(callback, *args, **kwargs):
33    """Invoke a callback, swallowing and logging any exceptions."""
34    # pylint: disable=bare-except
35    # We intentionally want to swallow all exceptions.
36    try:
37        return callback(*args, **kwargs)
38    except Exception:
39        _LOGGER.exception("Error while executing Future callback.")
40