311822ecdc
This change introduces an sqlite database that contains the track_id, db insertion time, and ttl in the cache. The ttl starts with one week, and increases exponentially by a factor of 2 each time the same track_id is added to the database. This significantly reduces the execution of the time script when there are a lot of match failures accumulating, which do not need to check every time.
64 lines
2.9 KiB
Python
64 lines
2.9 KiB
Python
import datetime
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import sqlalchemy
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from sqlalchemy import Table, Column, String, DateTime, MetaData, insert, select, update, delete
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class Database:
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def __init__(self, filename='.cache.db'):
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self.engine = sqlalchemy.create_engine(f"sqlite:///{filename}")
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meta = MetaData()
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self.match_failures = Table('match_failures', meta,
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Column('track_id', String,
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primary_key=True),
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Column('insert_time', DateTime),
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Column('next_retry', DateTime),
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sqlite_autoincrement=False)
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meta.create_all(self.engine)
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def _get_next_retry_time(self, insert_time=None):
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if insert_time:
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# double interval on each retry
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interval = 2 * (datetime.datetime.now() - insert_time)
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else:
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interval = datetime.timedelta(days=7)
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return datetime.datetime.now() + interval
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def cache_match_failure(self, track_id):
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""" notifies that matching failed for the given track_id """
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fetch_statement = select(self.match_failures).where(
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self.match_failures.c.track_id == track_id)
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with self.engine.connect() as connection:
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with connection.begin():
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# Either update the next_retry time if track_id already exists, otherwise create a new entry
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existing_failure = connection.execute(
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fetch_statement).fetchone()
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if existing_failure:
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update_statement = update(self.match_failures).where(
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self.match_failures.c.track_id == track_id).values(next_retry=self._get_next_retry_time())
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connection.execute(update_statement)
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else:
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connection.execute(insert(self.match_failures), {
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"track_id": track_id, "insert_time": datetime.datetime.now(), "next_retry": self._get_next_retry_time()})
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def has_match_failure(self, track_id):
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""" checks if there was a recent search for which matching failed with the given track_id """
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statement = select(self.match_failures.c.next_retry).where(
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self.match_failures.c.track_id == track_id)
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with self.engine.connect() as connection:
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match_failure = connection.execute(statement).fetchone()
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if match_failure:
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return match_failure.next_retry > datetime.datetime.now()
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return False
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def remove_match_failure(self, track_id):
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""" removes match failure from the database """
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statement = delete(self.match_failures).where(
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self.match_failures.c.track_id == track_id)
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with self.engine.connect() as connection:
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with connection.begin():
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connection.execute(statement)
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# Main singleton instance
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failure_cache = Database()
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