70 lines
2.0 KiB
Python
70 lines
2.0 KiB
Python
# Copyright 2020 Canonical, Ltd.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import asyncio
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import contextlib
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from systemd import journal
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def journald_listen(identifiers, callback, seek=False):
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reader = journal.Reader()
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args = []
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for identifier in identifiers:
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if "=" in identifier:
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args.append(identifier)
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else:
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args.append("SYSLOG_IDENTIFIER={}".format(identifier))
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reader.add_match(*args)
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if seek:
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reader.seek_tail()
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def watch():
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if reader.process() != journal.APPEND:
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return
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for event in reader:
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callback(event)
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loop = asyncio.get_running_loop()
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loop.add_reader(reader.fileno(), watch)
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return reader.fileno()
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@contextlib.contextmanager
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def journald_subscriptions(ids_callbacks, seek=False):
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fds = set()
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for ids, callback in ids_callbacks:
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fds.add(journald_listen(ids, callback, seek=seek))
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try:
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yield
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finally:
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loop = asyncio.get_running_loop()
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for fd in fds:
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loop.remove_reader(fd)
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async def journald_get_first_match(*identifiers, seek=False):
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def cb(_event):
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nonlocal event
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event = _event
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found.set()
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event = None
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found = asyncio.Event()
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with journald_subscriptions(((identifiers, cb),), seek=seek):
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await found.wait()
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return event
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