195 lines
8.5 KiB
Python
195 lines
8.5 KiB
Python
import logging
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from peewee import JOIN_LEFT_OUTER, fn
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from data.model import config, db_transaction, InvalidImageException
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from data.database import (ImageStorage, Image, DerivedImageStorage, ImageStoragePlacement,
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ImageStorageLocation, ImageStorageTransformation, ImageStorageSignature,
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ImageStorageSignatureKind)
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logger = logging.getLogger(__name__)
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def find_or_create_derived_storage(source, transformation_name, preferred_location):
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existing = find_derived_storage(source, transformation_name)
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if existing is not None:
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return existing
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logger.debug('Creating storage dervied from source: %s', source.uuid)
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trans = ImageStorageTransformation.get(name=transformation_name)
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new_storage = create_storage(preferred_location)
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DerivedImageStorage.create(source=source, derivative=new_storage, transformation=trans)
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return new_storage
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def garbage_collect_storage(storage_id_whitelist):
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if len(storage_id_whitelist) == 0:
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return
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def placements_query_to_paths_set(placements_query):
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return {(placement.location.name, config.store.image_path(placement.storage.uuid))
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for placement in placements_query}
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def orphaned_storage_query(select_base_query, candidates, group_by):
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return (select_base_query
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.switch(ImageStorage)
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.join(Image, JOIN_LEFT_OUTER)
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.switch(ImageStorage)
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.join(DerivedImageStorage, JOIN_LEFT_OUTER,
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on=(ImageStorage.id == DerivedImageStorage.derivative))
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.where(ImageStorage.id << list(candidates))
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.group_by(*group_by)
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.having((fn.Count(Image.id) == 0) & (fn.Count(DerivedImageStorage.id) == 0)))
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# Note: We remove the derived image storage in its own transaction as a way to reduce the
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# time that the transaction holds on the database indicies. This could result in a derived
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# image storage being deleted for an image storage which is later reused during this time,
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# but since these are caches anyway, it isn't terrible and worth the tradeoff (for now).
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logger.debug('Garbage collecting derived storage from candidates: %s', storage_id_whitelist)
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with db_transaction():
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# Find out which derived storages will be removed, and add them to the whitelist
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# The comma after ImageStorage.id is VERY important, it makes it a tuple, which is a sequence
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orphaned_from_candidates = list(orphaned_storage_query(ImageStorage.select(ImageStorage.id),
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storage_id_whitelist,
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(ImageStorage.id,)))
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if len(orphaned_from_candidates) > 0:
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derived_to_remove = (ImageStorage
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.select(ImageStorage.id)
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.join(DerivedImageStorage,
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on=(ImageStorage.id == DerivedImageStorage.derivative))
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.where(DerivedImageStorage.source << orphaned_from_candidates))
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storage_id_whitelist.update({derived.id for derived in derived_to_remove})
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# Remove the dervived image storages with sources of orphaned storages
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(DerivedImageStorage
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.delete()
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.where(DerivedImageStorage.source << orphaned_from_candidates)
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.execute())
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# Note: Both of these deletes must occur in the same transaction (unfortunately) because a
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# storage without any placement is invalid, and a placement cannot exist without a storage.
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# TODO(jake): We might want to allow for null storages on placements, which would allow us to
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# delete the storages, then delete the placements in a non-transaction.
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logger.debug('Garbage collecting storages from candidates: %s', storage_id_whitelist)
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with db_transaction():
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# Track all of the data that should be removed from blob storage
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placements_to_remove = list(orphaned_storage_query(ImageStoragePlacement
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.select(ImageStoragePlacement,
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ImageStorage,
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ImageStorageLocation)
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.join(ImageStorageLocation)
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.switch(ImageStoragePlacement)
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.join(ImageStorage),
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storage_id_whitelist,
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(ImageStorage, ImageStoragePlacement,
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ImageStorageLocation)))
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paths_to_remove = placements_query_to_paths_set(placements_to_remove)
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# Remove the placements for orphaned storages
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if len(placements_to_remove) > 0:
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placement_ids_to_remove = [placement.id for placement in placements_to_remove]
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placements_removed = (ImageStoragePlacement
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.delete()
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.where(ImageStoragePlacement.id << placement_ids_to_remove)
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.execute())
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logger.debug('Removed %s image storage placements', placements_removed)
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# Remove all orphaned storages
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# The comma after ImageStorage.id is VERY important, it makes it a tuple, which is a sequence
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orphaned_storages = list(orphaned_storage_query(ImageStorage.select(ImageStorage.id),
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storage_id_whitelist,
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(ImageStorage.id,)).alias('osq'))
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if len(orphaned_storages) > 0:
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storages_removed = (ImageStorage
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.delete()
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.where(ImageStorage.id << orphaned_storages)
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.execute())
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logger.debug('Removed %s image storage records', storages_removed)
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# We are going to make the conscious decision to not delete image storage blobs inside
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# transactions.
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# This may end up producing garbage in s3, trading off for higher availability in the database.
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for location_name, image_path in paths_to_remove:
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logger.debug('Removing %s from %s', image_path, location_name)
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config.store.remove({location_name}, image_path)
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def create_storage(location_name):
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storage = ImageStorage.create()
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location = ImageStorageLocation.get(name=location_name)
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ImageStoragePlacement.create(location=location, storage=storage)
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storage.locations = {location_name}
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return storage
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def find_or_create_storage_signature(storage, signature_kind):
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found = lookup_storage_signature(storage, signature_kind)
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if found is None:
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kind = ImageStorageSignatureKind.get(name=signature_kind)
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found = ImageStorageSignature.create(storage=storage, kind=kind)
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return found
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def lookup_storage_signature(storage, signature_kind):
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kind = ImageStorageSignatureKind.get(name=signature_kind)
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try:
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return (ImageStorageSignature
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.select()
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.where(ImageStorageSignature.storage == storage,
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ImageStorageSignature.kind == kind)
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.get())
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except ImageStorageSignature.DoesNotExist:
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return None
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def find_derived_storage(source, transformation_name):
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try:
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found = (ImageStorage
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.select(ImageStorage, DerivedImageStorage)
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.join(DerivedImageStorage, on=(ImageStorage.id == DerivedImageStorage.derivative))
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.join(ImageStorageTransformation)
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.where(DerivedImageStorage.source == source,
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ImageStorageTransformation.name == transformation_name)
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.get())
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found.locations = {placement.location.name for placement in found.imagestorageplacement_set}
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return found
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except ImageStorage.DoesNotExist:
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return None
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def delete_derived_storage_by_uuid(storage_uuid):
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try:
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image_storage = get_storage_by_uuid(storage_uuid)
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except InvalidImageException:
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return
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try:
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DerivedImageStorage.get(derivative=image_storage)
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except DerivedImageStorage.DoesNotExist:
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return
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image_storage.delete_instance(recursive=True)
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def get_storage_by_uuid(storage_uuid):
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placements = list(ImageStoragePlacement
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.select(ImageStoragePlacement, ImageStorage, ImageStorageLocation)
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.join(ImageStorageLocation)
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.switch(ImageStoragePlacement)
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.join(ImageStorage)
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.where(ImageStorage.uuid == storage_uuid))
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if not placements:
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raise InvalidImageException('No storage found with uuid: %s', storage_uuid)
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found = placements[0].storage
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found.locations = {placement.location.name for placement in placements}
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return found
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