e2f359c352
* Drop crawl stats fields from CrawlConfig and add migration * Remove migrate_down from BaseMigration * Get crawl stats from optimized mongo query
69 lines
2.3 KiB
Python
69 lines
2.3 KiB
Python
"""
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BaseMigration class to subclass in each migration module
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"""
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from pymongo.errors import OperationFailure
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class BaseMigration:
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"""Base Migration class."""
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def __init__(self, mdb, migration_version="0001"):
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self.mdb = mdb
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self.migration_version = migration_version
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async def get_db_version(self):
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"""Get current db version from database."""
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db_version = None
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version_collection = self.mdb["version"]
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version_record = await version_collection.find_one()
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if not version_record:
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return db_version
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try:
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db_version = version_record["version"]
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except KeyError:
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pass
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return db_version
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async def set_db_version(self):
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"""Set db version to migration_version."""
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version_collection = self.mdb["version"]
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await version_collection.find_one_and_update(
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{}, {"$set": {"version": self.migration_version}}, upsert=True
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)
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async def migrate_up_needed(self):
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"""Verify migration up is needed and return boolean indicator."""
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db_version = await self.get_db_version()
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print(f"Current database version before migration: {db_version}")
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print(f"Migration available to apply: {self.migration_version}")
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# Databases from prior to migrations will not have a version set.
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if not db_version:
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return True
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if db_version < self.migration_version:
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return True
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return False
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async def migrate_up(self):
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"""Perform migration up."""
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raise NotImplementedError(
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"Not implemented in base class - implement in subclass"
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)
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async def run(self):
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"""Run migrations."""
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if await self.migrate_up_needed():
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print("Performing migration up", flush=True)
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try:
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await self.migrate_up()
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await self.set_db_version()
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except OperationFailure as err:
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print(f"Error running migration {self.migration_version}: {err}")
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return False
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else:
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print("No migration to apply - skipping", flush=True)
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return False
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print(f"Database successfully migrated to {self.migration_version}", flush=True)
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return True
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