66 lines
2.7 KiB
Python
66 lines
2.7 KiB
Python
"""Purge old data helper."""
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from datetime import timedelta
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import logging
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import homeassistant.util.dt as dt_util
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from .util import session_scope
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_LOGGER = logging.getLogger(__name__)
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def purge_old_data(instance, purge_days):
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"""Purge events and states older than purge_days ago."""
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from .models import States, Events
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from sqlalchemy import orm
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from sqlalchemy.sql import exists
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purge_before = dt_util.utcnow() - timedelta(days=purge_days)
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with session_scope(session=instance.get_session()) as session:
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# For each entity, the most recent state is protected from deletion
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# s.t. we can properly restore state even if the entity has not been
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# updated in a long time
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states_alias = orm.aliased(States, name='StatesAlias')
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protected_states = session.query(States.state_id, States.event_id)\
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.filter(~exists()
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.where(States.entity_id ==
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states_alias.entity_id)
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.where(states_alias.last_updated >
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States.last_updated))\
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.all()
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protected_state_ids = tuple((state[0] for state in protected_states))
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protected_event_ids = tuple((state[1] for state in protected_states
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if state[1] is not None))
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deleted_rows = session.query(States) \
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.filter((States.last_updated < purge_before)) \
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.filter(~States.state_id.in_(
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protected_state_ids)) \
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.delete(synchronize_session=False)
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_LOGGER.debug("Deleted %s states", deleted_rows)
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# We also need to protect the events belonging to the protected states.
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# Otherwise, if the SQL server has "ON DELETE CASCADE" as default, it
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# will delete the protected state when deleting its associated
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# event. Also, we would be producing NULLed foreign keys otherwise.
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deleted_rows = session.query(Events) \
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.filter((Events.time_fired < purge_before)) \
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.filter(~Events.event_id.in_(
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protected_event_ids
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)) \
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.delete(synchronize_session=False)
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_LOGGER.debug("Deleted %s events", deleted_rows)
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# Execute sqlite vacuum command to free up space on disk
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_LOGGER.debug("DB engine driver: %s", instance.engine.driver)
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if instance.engine.driver == 'pysqlite':
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from sqlalchemy import exc
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_LOGGER.info("Vacuuming SQLite to free space")
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try:
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instance.engine.execute("VACUUM")
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except exc.OperationalError as err:
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_LOGGER.error("Error vacuuming SQLite: %s.", err)
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