mirror of
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86 lines
2.6 KiB
Python
86 lines
2.6 KiB
Python
#
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# This file is part of Glances.
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#
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# SPDX-FileCopyrightText: 2022 Nicolas Hennion <nicolas@nicolargo.com>
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#
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# SPDX-License-Identifier: LGPL-3.0-only
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import threading
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import time
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from glances.logger import logger
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class ThreadedIterableStreamer:
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"""
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Utility class to stream an iterable using a background / daemon Thread
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Use `ThreadedIterableStreamer.stats` to access the latest streamed results
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"""
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def __init__(self, iterable, initial_stream_value=None, sleep_duration=0.1):
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"""
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iterable: an Iterable instance that needs to be streamed
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"""
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self._iterable = iterable
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# Iterable results are stored here
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self._raw_result = initial_stream_value
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# Use a Thread to stream iterable (daemon=True to automatically kill thread when main process dies)
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self._thread = threading.Thread(target=self._stream_results, daemon=True)
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# Event needed to stop the thread manually
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self._stopper = threading.Event()
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# Lock to avoid the daemon thread updating stats when main thread reads the stats
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self.result_lock = threading.Lock()
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# Last result streamed time (initial val 0)
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self._last_update_time = 0
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# Time to sleep before next iteration
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self._sleep_duration = sleep_duration
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self._thread.start()
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def stop(self):
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"""Stop the thread."""
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self._stopper.set()
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def stopped(self):
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"""Return True is the thread is stopped."""
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return self._stopper.is_set()
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def _stream_results(self):
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"""Grab the stats.
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Infinite loop, should be stopped by calling the stop() method
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"""
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try:
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for res in self._iterable:
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self._pre_update_hook()
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self._raw_result = res
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self._post_update_hook()
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time.sleep(self._sleep_duration)
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if self.stopped():
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break
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except Exception as e:
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logger.debug(f"docker plugin - Exception thrown during run ({e})")
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self.stop()
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def _pre_update_hook(self):
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"""Hook that runs before worker thread updates the raw_stats"""
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self.result_lock.acquire()
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def _post_update_hook(self):
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"""Hook that runs after worker thread updates the raw_stats"""
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self._last_update_time = time.time()
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self.result_lock.release()
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@property
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def stats(self):
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"""Raw Stats getter."""
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return self._raw_result
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@property
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def last_update_time(self):
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"""Raw Stats getter."""
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return self._last_update_time
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