Source code for thoth.storages.ceph_cache

#!/usr/bin/env python3
# thoth-storages
# Copyright(C) 2018, 2019, 2020 Fridolin Pokorny
# This program is free software: you can redistribute it and / or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <>.

"""A base class for implementing caches based on Ceph."""

from datetime import datetime
from datetime import timedelta
from datetime import timezone

from .exceptions import CacheMiss
from .exceptions import NotFoundError
from .result_base import ResultStorageBase

[docs]class CephCache(ResultStorageBase): """A base class implementing cache interface."""
[docs] def retrieve_document_record(self, document_id: str) -> dict: """Check whether the given record exists in the cache for the requested document.""" try: return self.retrieve_document(document_id) except NotFoundError as exc: raise CacheMiss(f"There was no record found in the cache for {document_id!r}") from exc
[docs] def store_document_record(self, document_id: str, document: dict) -> None: """Store the given document record in the cache.""" self.ceph.store_document(document, document_id)
[docs] def retrieve_document_ttl(self, document_id: str) -> float: """Retrieve the TTL for a cached document.""" # Verify if the document is present in the cache self.retrieve_document_record(document_id) # Uses UTC time to be environment agnostic (no timezone) time_lived = - self.ceph.retrieve_document_attr( object_key=document_id, attr="LastModified" ).replace(tzinfo=timezone.utc) if time_lived <= timedelta(hours=4): return (timedelta(hours=4) - time_lived).total_seconds() return 0.0