126 lines
4 KiB
Python
126 lines
4 KiB
Python
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#
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# Copyright (C) 2018 Red Hat, Inc.
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#
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# This copyrighted material is made available to anyone wishing to use,
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# modify, copy, or redistribute it subject to the terms and conditions of
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# the GNU General Public License v.2, or (at your option) any later version.
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY expressed or implied, including the implied warranties of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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# Public License for more details. You should have received a copy of the
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# GNU General Public License along with this program; if not, write to the
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# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA. Any Red Hat trademarks that are incorporated in the
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# source code or documentation are not subject to the GNU General Public
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# License and may only be used or replicated with the express permission of
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# Red Hat, Inc.
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#
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from abc import ABC, abstractmethod
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from pyanaconda.core.signal import Signal
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from pyanaconda.core.async_utils import async_action_nowait
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__all__ = ['Runnable']
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class Runnable(ABC):
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"""Abstract class that allows to run a task."""
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def __init__(self):
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super().__init__()
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self._started_signal = Signal()
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self._stopped_signal = Signal()
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self._failed_signal = Signal()
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self._succeeded_signal = Signal()
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@property
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def started_signal(self):
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"""Signal emitted when the task starts."""
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return self._started_signal
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@property
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def stopped_signal(self):
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"""Signal emitted when the task stops."""
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return self._stopped_signal
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@property
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def failed_signal(self):
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"""Signal emitted when the task fails."""
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return self._failed_signal
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@property
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def succeeded_signal(self):
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"""Signal emitted when the task succeeds."""
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return self._succeeded_signal
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@property
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@abstractmethod
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def is_running(self):
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"""Is the task running."""
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return False
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@abstractmethod
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def start(self):
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"""Start the task run.
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Your task should run the following callbacks:
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self._task_started_callback
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self._task_run_callback
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self._task_failed_callback
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self._task_succeeded_callback
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self._task_stopped_callback
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Make sure that you call self._task_started_callback at the
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beginning of the task lifetime to inform that the task is
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running now. Run self._task_run_callback to do the actual
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job of the task.
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In a case of failure, call self._task_failed_callback to
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inform that the task has failed. You will still need to
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call also self._task_stopped_callback.
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In a case of success, call self._task_succeeded_callback to
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inform that the task has succeeded.
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Make sure that you always call self._task_stopped_callback
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at the end of the task lifetime to inform that the task is
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not running anymore.
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"""
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pass
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@async_action_nowait
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def _task_started_callback(self):
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"""Callback for a started task."""
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self._started_signal.emit()
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@abstractmethod
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def _task_run_callback(self):
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"""Run the task."""
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pass
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@async_action_nowait
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def _task_failed_callback(self):
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"""Callback for a failed task."""
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self._failed_signal.emit()
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@async_action_nowait
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def _task_succeeded_callback(self):
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"""Callback for a successful task."""
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self._succeeded_signal.emit()
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@async_action_nowait
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def _task_stopped_callback(self):
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"""Callback for a terminated task."""
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self._stopped_signal.emit()
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@abstractmethod
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def finish(self):
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"""Finish the task run.
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This method should be called after the task was started and stopped.
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Re-raise any exception that was raised during the task run and wasn't
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propagated by the self.start method.
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"""
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pass
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