pytorch-lightning

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# Copyright The Lightning AI team.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import threading
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from datetime import datetime
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from typing import Optional
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from croniter import croniter
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from deepdiff import Delta
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from lightning.app.utilities.proxies import ComponentDelta
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class SchedulerThread(threading.Thread):
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    # TODO (tchaton) Abstract this logic to a generic scheduling service.
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    def __init__(self, app) -> None:
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        super().__init__(daemon=True)
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        self._exit_event = threading.Event()
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        self._sleep_time = 1.0
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        self._app = app
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    def run(self) -> None:
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        while not self._exit_event.is_set():
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            self._exit_event.wait(self._sleep_time)
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            self.run_once()
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    def run_once(self):
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        for call_hash in list(self._app._schedules.keys()):
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            metadata = self._app._schedules[call_hash]
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            start_time = datetime.fromisoformat(metadata["start_time"])
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            current_date = datetime.now()
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            next_event = croniter(metadata["cron_pattern"], start_time).get_next(datetime)
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            # When the event is reached, send a delta to activate scheduling.
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            if current_date > next_event:
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                component_delta = ComponentDelta(
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                    id=metadata["name"],
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                    delta=Delta({
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                        "values_changed": {
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                            f"root['calls']['scheduling']['{call_hash}']['running']": {"new_value": True}
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                        }
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                    }),
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                )
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                self._app.delta_queue.put(component_delta)
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                metadata["start_time"] = next_event.isoformat()
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    def join(self, timeout: Optional[float] = None) -> None:
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        self._exit_event.set()
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        super().join(timeout)
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