120 lines
4.7 KiB
Python
120 lines
4.7 KiB
Python
# coding: utf-8
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from __future__ import unicode_literals
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from django.conf import settings
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from django.db import connections
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from django.utils.six import string_types
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from .cache import cachalot_caches
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from .settings import cachalot_settings
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from .signals import post_invalidation
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from .transaction import AtomicCache
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from .utils import _invalidate_tables
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__all__ = ('invalidate', 'get_last_invalidation')
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def _cache_db_tables_iterator(tables, cache_alias, db_alias):
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no_tables = not tables
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cache_aliases = settings.CACHES if cache_alias is None else (cache_alias,)
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db_aliases = settings.DATABASES if db_alias is None else (db_alias,)
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for db_alias in db_aliases:
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if no_tables:
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tables = connections[db_alias].introspection.table_names()
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if tables:
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for cache_alias in cache_aliases:
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yield cache_alias, db_alias, tables
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def _get_tables(tables_or_models):
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return [o if isinstance(o, string_types) else o._meta.db_table
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for o in tables_or_models]
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def invalidate(*tables_or_models, **kwargs):
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"""
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Clears what was cached by django-cachalot implying one or more SQL tables
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or models from ``tables_or_models``.
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If ``tables_or_models`` is not specified, all tables found in the database
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(including those outside Django) are invalidated.
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If ``cache_alias`` is specified, it only clears the SQL queries stored
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on this cache, otherwise queries from all caches are cleared.
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If ``db_alias`` is specified, it only clears the SQL queries executed
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on this database, otherwise queries from all databases are cleared.
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:arg tables_or_models: SQL tables names or models (or combination of both)
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:type tables_or_models: tuple of strings or models
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:arg cache_alias: Alias from the Django ``CACHES`` setting
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:type cache_alias: string or NoneType
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:arg db_alias: Alias from the Django ``DATABASES`` setting
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:type db_alias: string or NoneType
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:returns: Nothing
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:rtype: NoneType
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"""
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# TODO: Replace with positional arguments when we drop Python 2 support.
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cache_alias = kwargs.pop('cache_alias', None)
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db_alias = kwargs.pop('db_alias', None)
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for k in kwargs:
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raise TypeError(
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"invalidate() got an unexpected keyword argument '%s'" % k)
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send_signal = False
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invalidated = set()
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for cache_alias, db_alias, tables in _cache_db_tables_iterator(
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_get_tables(tables_or_models), cache_alias, db_alias):
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cache = cachalot_caches.get_cache(cache_alias, db_alias)
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if not isinstance(cache, AtomicCache):
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send_signal = True
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_invalidate_tables(cache, db_alias, tables)
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invalidated.update(tables)
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if send_signal:
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for table in invalidated:
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post_invalidation.send(table, db_alias=db_alias)
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def get_last_invalidation(*tables_or_models, **kwargs):
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"""
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Returns the timestamp of the most recent invalidation of the given
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``tables_or_models``. If ``tables_or_models`` is not specified,
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all tables found in the database (including those outside Django) are used.
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If ``cache_alias`` is specified, it only fetches invalidations
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in this cache, otherwise invalidations in all caches are fetched.
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If ``db_alias`` is specified, it only fetches invalidations
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for this database, otherwise invalidations for all databases are fetched.
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:arg tables_or_models: SQL tables names or models (or combination of both)
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:type tables_or_models: tuple of strings or models
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:arg cache_alias: Alias from the Django ``CACHES`` setting
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:type cache_alias: string or NoneType
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:arg db_alias: Alias from the Django ``DATABASES`` setting
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:type db_alias: string or NoneType
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:returns: The timestamp of the most recent invalidation
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:rtype: float
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"""
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# TODO: Replace with positional arguments when we drop Python 2 support.
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cache_alias = kwargs.pop('cache_alias', None)
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db_alias = kwargs.pop('db_alias', None)
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for k in kwargs:
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raise TypeError("get_last_invalidation() got an unexpected "
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"keyword argument '%s'" % k)
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last_invalidation = 0.0
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for cache_alias, db_alias, tables in _cache_db_tables_iterator(
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_get_tables(tables_or_models), cache_alias, db_alias):
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get_table_cache_key = cachalot_settings.CACHALOT_TABLE_KEYGEN
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table_cache_keys = [get_table_cache_key(db_alias, t) for t in tables]
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invalidations = cachalot_caches.get_cache(
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cache_alias, db_alias).get_many(table_cache_keys).values()
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if invalidations:
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current_last_invalidation = max(invalidations)
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if current_last_invalidation > last_invalidation:
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last_invalidation = current_last_invalidation
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return last_invalidation
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