Fixed #15888 -- Made tablename argument of createcachetable optional

Thanks Aymeric Augustin for the report and the documentation and
Tim Graham for the review.
This commit is contained in:
Claude Paroz 2013-01-05 23:43:01 +01:00
parent b600bb7e08
commit 1e8eadc94e
7 changed files with 130 additions and 58 deletions

View File

@ -1,8 +1,6 @@
import os
from django.conf import settings
from django.core.cache import get_cache
from django.core.cache.backends.db import BaseDatabaseCache
from django.core.exceptions import ImproperlyConfigured
from django.db.backends.sqlite3.creation import DatabaseCreation
@ -55,10 +53,7 @@ class SpatiaLiteCreation(DatabaseCreation):
interactive=False,
database=self.connection.alias)
for cache_alias in settings.CACHES:
cache = get_cache(cache_alias)
if isinstance(cache, BaseDatabaseCache):
call_command('createcachetable', cache._table, database=self.connection.alias)
call_command('createcachetable', database=self.connection.alias)
# Get a cursor (even though we don't need one yet). This has
# the side effect of initializing the test database.

View File

@ -1,32 +1,50 @@
from optparse import make_option
from django.conf import settings
from django.core.cache import get_cache
from django.core.cache.backends.db import BaseDatabaseCache
from django.core.management.base import LabelCommand, CommandError
from django.core.management.base import BaseCommand, CommandError
from django.db import connections, router, transaction, models, DEFAULT_DB_ALIAS
from django.db.utils import DatabaseError
from django.utils.encoding import force_text
class Command(LabelCommand):
help = "Creates the table needed to use the SQL cache backend."
args = "<tablename>"
label = 'tablename'
class Command(BaseCommand):
help = "Creates the tables needed to use the SQL cache backend."
option_list = LabelCommand.option_list + (
option_list = BaseCommand.option_list + (
make_option('--database', action='store', dest='database',
default=DEFAULT_DB_ALIAS, help='Nominates a database onto '
'which the cache table will be installed. '
'which the cache tables will be installed. '
'Defaults to the "default" database.'),
)
requires_model_validation = False
def handle_label(self, tablename, **options):
def handle(self, *tablenames, **options):
db = options.get('database')
self.verbosity = int(options.get('verbosity'))
if len(tablenames):
# Legacy behavior, tablename specified as argument
for tablename in tablenames:
self.create_table(db, tablename)
else:
for cache_alias in settings.CACHES:
cache = get_cache(cache_alias)
if isinstance(cache, BaseDatabaseCache):
self.create_table(db, cache._table)
def create_table(self, database, tablename):
cache = BaseDatabaseCache(tablename, {})
if not router.allow_migrate(db, cache.cache_model_class):
if not router.allow_migrate(database, cache.cache_model_class):
return
connection = connections[db]
connection = connections[database]
if tablename in connection.introspection.table_names():
if self.verbosity > 0:
self.stdout.write("Cache table '%s' already exists." % tablename)
return
fields = (
# "key" is a reserved word in MySQL, so use "cache_key" instead.
models.CharField(name='cache_key', max_length=255, unique=True, primary_key=True),
@ -63,3 +81,5 @@ class Command(LabelCommand):
(tablename, force_text(e)))
for statement in index_output:
curs.execute(statement)
if self.verbosity > 1:
self.stdout.write("Cache table '%s' created." % tablename)

View File

@ -356,13 +356,7 @@ class BaseDatabaseCreation(object):
interactive=False,
database=self.connection.alias)
from django.core.cache import get_cache
from django.core.cache.backends.db import BaseDatabaseCache
for cache_alias in settings.CACHES:
cache = get_cache(cache_alias)
if isinstance(cache, BaseDatabaseCache):
call_command('createcachetable', cache._table,
database=self.connection.alias)
call_command('createcachetable', database=self.connection.alias)
# Get a cursor (even though we don't need one yet). This has
# the side effect of initializing the test database.

View File

@ -131,12 +131,19 @@ createcachetable
.. django-admin:: createcachetable
Creates a cache table named ``tablename`` for use with the database cache
backend. See :doc:`/topics/cache` for more information.
Creates the cache tables for use with the database cache backend. See
:doc:`/topics/cache` for more information.
The :djadminopt:`--database` option can be used to specify the database
onto which the cachetable will be installed.
.. versionchanged:: 1.7
It is no longer necessary to provide the cache table name or the
:djadminopt:`--database` option. Django takes this information from your
settings file. If you have configured multiple caches or multiple databases,
all cache tables are created.
dbshell
-------

View File

@ -305,6 +305,11 @@ Management Commands
``use_natural_primary_keys`` arguments for ``serializers.serialize()``, allow
the use of natural primary keys when serializing.
* It is no longer necessary to provide the cache table name or the
:djadminopt:`--database` option for the :djadmin:`createcachetable` command.
Django takes this information from your settings file. If you have configured
multiple caches or multiple databases, all cache tables are created.
Models
^^^^^^

View File

@ -159,22 +159,18 @@ particularly temporary.
Database caching
----------------
To use a database table as your cache backend, first create a cache table in
your database by running this command::
Django can store its cached data in your database. This works best if you've
got a fast, well-indexed database server.
$ python manage.py createcachetable [cache_table_name]
To use a database table as your cache backend:
...where ``[cache_table_name]`` is the name of the database table to create.
(This name can be whatever you want, as long as it's a valid table name that's
not already being used in your database.) This command creates a single table
in your database that is in the proper format that Django's database-cache
system expects.
* Set :setting:`BACKEND <CACHES-BACKEND>` to
``django.core.cache.backends.db.DatabaseCache``
* Set :setting:`LOCATION <CACHES-LOCATION>` to ``tablename``, the name of
the database table. This name can be whatever you want, as long as it's
a valid table name that's not already being used in your database.
Once you've created that database table, set your
:setting:`BACKEND <CACHES-BACKEND>` setting to
``"django.core.cache.backends.db.DatabaseCache"``, and
:setting:`LOCATION <CACHES-LOCATION>` to ``tablename`` -- the name of the
database table. In this example, the cache table's name is ``my_cache_table``::
In this example, the cache table's name is ``my_cache_table``::
CACHES = {
'default': {
@ -183,14 +179,36 @@ database table. In this example, the cache table's name is ``my_cache_table``::
}
}
Creating the cache table
~~~~~~~~~~~~~~~~~~~~~~~~
The database caching backend uses the same database as specified in your
settings file. You can't use a different database backend for your cache table.
Before using the database cache, you must create the cache table with this
command::
Database caching works best if you've got a fast, well-indexed database server.
python manage.py createcachetable
Database caching and multiple databases
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This creates a table in your database that is in the proper format that
Django's database-cache system expects. The name of the table is taken from
:setting:`LOCATION <CACHES-LOCATION>`.
If you are using multiple database caches, :djadmin:`createcachetable` creates
one table for each cache.
If you are using multiple databases, :djadmin:`createcachetable` observes the
``allow_migrate()`` method of your database routers (see below).
Like :djadmin:`migrate`, :djadmin:`createcachetable` won't touch an existing
table. It will only create missing tables.
.. versionchanged:: 1.7
Before Django 1.7, :djadmin:`createcachetable` created one table at a time.
You had to pass the name of the table you wanted to create, and if you were
using multiple databases, you had to use the :djadminopt:`--database`
option. For backwards compatibility, this is still possible.
Multiple databases
~~~~~~~~~~~~~~~~~~
If you use database caching with multiple databases, you'll also need
to set up routing instructions for your database cache table. For the

63
tests/cache/tests.py vendored
View File

@ -20,7 +20,7 @@ from django.core import management
from django.core.cache import get_cache
from django.core.cache.backends.base import (CacheKeyWarning,
InvalidCacheBackendError)
from django.db import router, transaction
from django.db import connection, router, transaction
from django.core.cache.utils import make_template_fragment_key
from django.http import (HttpResponse, HttpRequest, StreamingHttpResponse,
QueryDict)
@ -829,6 +829,14 @@ def custom_key_func(key, key_prefix, version):
return 'CUSTOM-' + '-'.join([key_prefix, str(version), key])
@override_settings(
CACHES={
'default': {
'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
'LOCATION': 'test cache table',
},
},
)
class DBCacheTests(BaseCacheTests, TransactionTestCase):
available_apps = ['cache']
@ -837,7 +845,7 @@ class DBCacheTests(BaseCacheTests, TransactionTestCase):
def setUp(self):
# Spaces are used in the table name to ensure quoting/escaping is working
self._table_name = 'test cache table'
management.call_command('createcachetable', self._table_name, verbosity=0, interactive=False)
management.call_command('createcachetable', verbosity=0, interactive=False)
self.cache = get_cache(self.backend_name, LOCATION=self._table_name, OPTIONS={'MAX_ENTRIES': 30})
self.prefix_cache = get_cache(self.backend_name, LOCATION=self._table_name, KEY_PREFIX='cacheprefix')
self.v2_cache = get_cache(self.backend_name, LOCATION=self._table_name, VERSION=2)
@ -845,7 +853,6 @@ class DBCacheTests(BaseCacheTests, TransactionTestCase):
self.custom_key_cache2 = get_cache(self.backend_name, LOCATION=self._table_name, KEY_FUNCTION='cache.tests.custom_key_func')
def tearDown(self):
from django.db import connection
cursor = connection.cursor()
cursor.execute('DROP TABLE %s' % connection.ops.quote_name(self._table_name))
connection.commit()
@ -858,14 +865,29 @@ class DBCacheTests(BaseCacheTests, TransactionTestCase):
self.perform_cull_test(50, 18)
def test_second_call_doesnt_crash(self):
with six.assertRaisesRegex(self, management.CommandError,
"Cache table 'test cache table' could not be created"):
management.call_command(
'createcachetable',
self._table_name,
verbosity=0,
interactive=False
)
stdout = six.StringIO()
management.call_command(
'createcachetable',
stdout=stdout
)
self.assertEqual(stdout.getvalue(),
"Cache table '%s' already exists.\n" % self._table_name)
def test_createcachetable_with_table_argument(self):
"""
Delete and recreate cache table with legacy behavior (explicitly
specifying the table name).
"""
self.tearDown()
stdout = six.StringIO()
management.call_command(
'createcachetable',
self._table_name,
verbosity=2,
stdout=stdout
)
self.assertEqual(stdout.getvalue(),
"Cache table '%s' created.\n" % self._table_name)
def test_clear_commits_transaction(self):
# Ensure the database transaction is committed (#19896)
@ -896,6 +918,14 @@ class DBCacheRouter(object):
return db == 'other'
@override_settings(
CACHES={
'default': {
'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
'LOCATION': 'my_cache_table',
},
},
)
class CreateCacheTableForDBCacheTests(TestCase):
multi_db = True
@ -905,13 +935,16 @@ class CreateCacheTableForDBCacheTests(TestCase):
router.routers = [DBCacheRouter()]
# cache table should not be created on 'default'
with self.assertNumQueries(0, using='default'):
management.call_command('createcachetable', 'cache_table',
management.call_command('createcachetable',
database='default',
verbosity=0, interactive=False)
# cache table should be created on 'other'
# one query is used to create the table and another one the index
with self.assertNumQueries(2, using='other'):
management.call_command('createcachetable', 'cache_table',
# Queries:
# 1: check table doesn't already exist
# 2: create the table
# 3: create the index
with self.assertNumQueries(3, using='other'):
management.call_command('createcachetable',
database='other',
verbosity=0, interactive=False)
finally: