Changelog — dogpile.cache 1.3.4 documentation

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# Changelog

## 1.3.4

Released: Tue Jan 28 2025

### usecase

- [usecase] [valkey]

  Added backend for valkey server. This is based on valkey-py as the driver.

  See also

  `ValkeyBackend`

### bug

- [bug] [redis]

  Fixes to the recently added `RedisClusterBackend` fixing a runtime typing error that prevented it from running.

  References: #263

### misc

- [change] [general]

  The pin for `setuptools<69.3` in `pyproject.toml` has been removed. This pin was to prevent a sudden change to PEP 625 in setuptools from taking place which changes the file name of SQLAlchemy’s source distribution on pypi to be an all lower case name, and the change was extended to all SQLAlchemy projects to prevent any further surprises. However, the presence of this pin is now holding back environments that otherwise want to use a newer setuptools, so we’ve decided to move forward with this change, with the assumption that build environments will have largely accommodated the setuptools change by now.

## 1.3.3

Released: Sun May 5 2024

### usecase

- [usecase] [memcached]

  Added support for an additional pymemcached client parameter `PyMemcacheBackend.memcached_expire_time`. Pull request courtesy Takashi Kajinami.

### bug

- [bug] [typing]

  Fixed the return type for `CacheRegion.get()`, which was inadvertently hardcoded to use `CacheReturnType` that only resolved to `CachedValue` or `NoValue`. Fixed to return `ValuePayload` which resolves to `Any`, as well as a new literal indicating an enum constant for `api.NO_VALUE`. The `api.NO_VALUE` constant remains available as the single element of this enum.

## 1.3.2

Released: Wed Feb 21 2024

### usecase

- [usecase] [redis]

  Added a new backend `RedisClusterBackend`, allowing support for Redis Cluster. Pull request courtesy Maël Naccache Tüfekçi.

  References: #250

- [usecase] [redis]

  Added support for additional Redis client parameters `RedisBackend.socket_connect_timeout`, `RedisBackend.socket_keepalive` and `RedisBackend.socket_keepalive_options`. Pull request courtesy Takashi Kajinami.

  References: #252

## 1.3.1

Released: Wed Feb 7 2024

### usecase

- [usecase] [redis]

  Added new parameter `RedisBackend.username` to the Redis backend, and `RedisSentinelBackend.username` to the Redis Sentinel backend. These parameters allow for username authentication in Redis when RBAC is enabled. Pull request courtesy Takashi Kajinami.

## 1.3.0

Released: Wed Dec 20 2023

### feature

- [feature] [region]

  Added new method `CacheRegion.get_value_metadata()` which can be used to get a value from the cache along with its metadata, including timestamp of when the value was cached. The `CachedValue` object is returned which features new accessors to retrieve cached time and current age. Pull request courtesy Grégoire Deveaux.

  References: #37

### misc

- [change] [setup]

  Minimum Python version is now Python 3.8; prior versions Python 3.7 and 3.6 are EOL.

- [change] [setup]

  Project setup is now based on pep-621 `pyproject.toml` configuration.

## 1.2.2

Released: Sat Jul 8 2023

### bug

- [bug] [typing]

  Made use of pep-673 `Self` type for method chained methods such as `CacheRegion.configure()` and `ProxyBackend.wrap()`. Pull request courtesy Viicos.

  References: #240

## 1.2.1

Released: Sat May 20 2023

### bug

- [bug] [typing]

  Added py.typed file to root so that typing tools such as Mypy recognize dogpile as typed. Pull request courtesy Daverball.

  References: #238

## 1.2.0

Released: Wed Apr 26 2023

### feature

- [feature] [region]

  Added new construct `api.CantDeserializeException` which can be raised by user-defined deserializer functions which would be passed to `CacheRegion.deserializer`, to indicate a cache value that can’t be deserialized and therefore should be regenerated. This can allow an application that’s been updated to gracefully re-cache old items that were persisted from a previous version of the application. Pull request courtesy Simon Hewitt.

  References: #236

## 1.1.8

Released: Fri Jul 8 2022

### bug

- [bug] [memcached]

  Moved the `MemcacheArgs.dead_retry` argument and the `MemcacheArgs.socket_timeout` argument which were erroneously added to the “set_parameters”, where they have no effect, to be part of the Memcached connection arguments `MemcachedBackend.dead_retry`, `MemcachedBackend.socket_timeout`.

  References: #223, #228

## 1.1.7

Released: Tue Jul 5 2022

### usecase

- [usecase] [memcached]

  Added `MemcacheArgs.dead_retry` and `MemcacheArgs.socket_timeout` to the dictionary of additional keyword arguments that will be passed directly to `GenericMemcachedBackend()`.

  References: #223

## 1.1.6

Released: Fri Jun 10 2022

### usecase

- [usecase] [redis]

  Added `RedisBackend.connection_kwargs` parameter, which is a dictionary of additional keyword arguments that will be passed directly to `StrictRedis()` or `StrictRedis.from_url()`, in the same way that this parameter works with the `RedisSentinelBackend` already.

  References: #221

### bug

- [bug] [redis]

  Fixed regression caused by backwards-incompatible API changes in Redis that caused the “distributed lock” feature to not function.

  References: #220

## 1.1.5

Released: Wed Jan 19 2022

### usecase

- [usecase] [memcached]

  Added support for additional pymemcache `HashClient` parameters `retry_attempts`, `retry_timeout`, and `dead_timeout`.

  See also

  `PyMemcacheBackend.hashclient_retry_attempts`

  `PyMemcacheBackend.hashclient_retry_timeout`

  `PyMemcacheBackend.dead_timeout`

## 1.1.4

Released: Thu Sep 2 2021

### usecase

- [usecase] [memcached]

  Added support for pymemcache socket keepalive and retrying client.

  See also

  `PyMemcacheBackend.socket_keepalive`

  `PyMemcacheBackend.enable_retry_client`

### bug

- [bug] [general]

  Fixed Python 3.10 deprecation warning involving threading. Pull request courtesy Karthikeyan Singaravelan.

  References: #203

## 1.1.3

Released: Thu May 20 2021

### bug

- [bug] [regression] [tests]

  Repaired the test suite to work with the 5.x series of the `decorator` module, which now appears to make use of the `__signature__` attribute.

- [bug] [regression]

  Fixed regression where `ProxyBackend` was missing several methods that were added as part of the 1.1 release.

  References: #202

## 1.1.2

Released: Tue Jan 26 2021

### feature

- [feature] [region]

  Added new region method `CacheRegion.key_is_locked()`. Returns True if the given key is subject to the dogpile lock, which would indicate that the generator function is running at that time. Pull request courtesy Bastien Gerard.

  References: #101

- [feature] [memcached]

  Added support for the pymemcache backend, using the `"dogpile.cache.pymemcache"` backend identifier. Pull request courtesy Moisés Guimarães de Medeiros.

  See also

  `PyMemcacheBackend`

  References: #134

## 1.1.1

Released: Mon Nov 23 2020

### bug

- [bug] [region]

  Fixed regression where the serialization and deserialization functions could be inadvertently turned into instance methods with an unexpected argument signature, namely when pickle.dumps and pickle.loads are the pure Python version as is the case in pypy.

  References: #195

## 1.1.0

Released: Sun Nov 15 2020

### feature

- [feature] [region]

  Reworked the means by which values are serialized and deserialized from backends, and provided for custom serialization of values. Added the `CacheRegion.serializer` and `CacheRegion.deserializer` parameters which may be set to any serializer.

  Serialization and deserialization now take place within the `CacheRegion` so that backends may now assume string values in all cases. This simplifies the existing backends and also makes custom backends easier to write and maintain.

  Additionally, the serializer is now applied to the user-defined value portion of the `CachedValue` and not to the metadata or other portions of `CachedValue` object itself, so the serialized portion is effectively a “payload” within the larger `CachedValue` structure that is passed as part of the larger string format. The overall format is a separate JSON of the cached value metadata, followed by the serialized form. This allows for end-user serialization schemes that are hardwired to the values themselves without the need to serialize dogpile’s internal structures as well.

  Existing custom backends should continue to work without issue; they now have the option to forego any separate serialization steps, and can also subclass a new backend `BytesBackend` that marks them as a backend that only deals with bytes coming in and out; all internal serialization logic from such a backend can be removed.

  Pull request courtesy Alessio Bogon.

  References: #191

### misc

- [change]

  Added pep-484 annotations to most of the dogpile.cache package.

## 1.0.2

Released: Fri Aug 7 2020

### feature

- [feature] [memcached]

  Added support for TLS connections to the bmemcached backend. Pull request courtesy Moisés Guimarães de Medeiros.

  References: #173

### bug

- [bug] [installation]

  Repaired the setup.cfg file so that the source and wheel distributions will not add the “tests” directory to the Python environment. Pull request courtesy Michał Górny.

## 1.0.1

Released: Tue Jul 21 2020

### bug

- [bug] [install]

  dogpile.cache 1.0.0 was released with a minimum Python version of 3.5. However, due to a dependency issue, the minimum version is now Python 3.6. The 1.0.0 release will be removed from PyPI so that Python versions prior to 3.6 will continue to make use of the previous dogpile.cache 0.9.2.

  References: #184

- [bug] [installation]

  Removed the “universal=1” directive from setup.cfg as this would create py2/py3 wheels. dogpile 1.0.x is Python 3 only so a py3-only wheel is now created.

  References: #185

## 1.0.0

Released: Sun Jul 19 2020

### feature

- [feature]

  Improved plugin scanner performance by switching from pkg_resources to stevedore.

- [feature] [redis]

  Added support for Redis Sentinel. Pull request courtesy Stéphane Brunner. See `RedisSentinelBackend`.

  References: #181

### misc

- [change: py3k]

  For version 1.0.0, dogpile.cache now supports Python 3.5 and above only.

## 0.9.2

Released: Mon May 4 2020

### bug

- [bug] [installation]

  Ensured that the “pyproject.toml” file is not included in builds, as the presence of this file indicates to pip that a pep-517 installation process should be used. As this mode of operation appears to be not well supported by current tools / distros, these problems are avoided within the scope of dogpile.cache installation by omitting the file.

  References: #178

## 0.9.1

Released: Wed Apr 29 2020

### bug

- [bug] [tests]

  Added `decorator` module as a required testing dependency to `tox.ini` so that tests work when this is not pre-installed.

- [bug] [redis]

  Added option to the Redis backend `RedisBackend.thread_local_lock`, which when set to False will disable the use of a threading local by the `redis` module in its distributed lock service, which is known to interfere with the lock’s behavior when used in an “async” use case, within dogpile this would be when using the `CacheRegion.async_creation_runner` feature. The default is conservatively being left at True, but it’s likely this should be set to False in all cases, so a warning is emitted if this flag is not set to False in conjunction with the distributed lock. Added an optional argument to `RedisBackend` that specifies whether or not a thread-local Redis lock should be used. This is the default, but it breaks asynchronous runner compatibility.

  References: #171

## 0.9.0

Released: Mon Oct 28 2019

### feature

- [feature]

  Added logging facililities into `CacheRegion`, to indicate key events such as cache keys missing or regeneration of values. As these can be very high volume log messages, `logging.DEBUG` is used as the log level for the events. Pull request courtesy Stéphane Brunner.

## 0.8.0

Released: Fri Sep 20 2019

### bug

- [bug] [setup]

  Removed the “python setup.py test” feature in favor of a straight run of “tox”. Per Pypa / pytest developers, “setup.py” commands are in general headed towards deprecation in favor of tox. The tox.ini script has been updated such that running “tox” with no arguments will perform a single run of the test suite against the default installed Python interpreter.

  See also

  pypa/setuptools#1684

  pytest-dev/pytest#5534

  References: #157

- [bug] [py3k]

  Replaced the Python compatbility routines for `getfullargspec()` with a fully vendored version from Python 3.3. Originally, Python was emitting deprecation warnings for this function in Python 3.8 alphas. While this change was reverted, it was observed that Python 3 implementations for `getfullargspec()` are an order of magnitude slower as of the 3.4 series where it was rewritten against `Signature`. While Python plans to improve upon this situation, SQLAlchemy projects for now are using a simple replacement to avoid any future issues.

  References: #154

- [bug] [installation]

  Pinned minimum version of Python decorator module at 4.0.0 (July, 2015) as previous versions don’t provide the API that dogpile is using.

  References: #160

- [bug] [py3k]

  Fixed the `sha1_mangle_key()` key mangler to coerce incoming Unicode objects into bytes as is required by the Py3k version of this function.

  References: #159

## 0.7.1

Released: Tue Dec 11 2018

### bug

- [bug] [region]

  Fixed regression in 0.7.0 caused by #136 where the assumed arguments for the `CacheRegion.async_creation_runner` expanded to include the new `CacheRegion.get_or_create.creator_args` parameter, as it was not tested that the async runner would be implicitly called with these arguments when the `CacheRegion.cache_on_arguments()` decorator was used. The exact signature of `async_creation_runner` is now restored to have the same arguments in all cases.

  References: #139

## 0.7.0

Released: Mon Dec 10 2018

### bug

- [bug]

  The `decorator` module is now used when creating function decorators within `CacheRegion.cache_on_arguments()` and `CacheRegion.cache_multi_on_arguments()` so that function signatures are preserved. Pull request courtesy ankitpatel96.

  Additionally adds a small performance enhancement which is to avoid internally creating a `@wraps()` decorator for the creator function on every get operation, by allowing the arguments to the creator be passed separately to `CacheRegion.get_or_create()`.

  References: #137

- [bug] [py3k]

  Fixed all Python 3.x deprecation warnings including `inspect.getargspec()`.

  References: #129

## 0.6.8

Released: Sat Nov 24 2018

- [change]

  Project hosting has moved to GitHub, under the SQLAlchemy organization at sqlalchemy/dogpile.cache

## 0.6.7

Released: Thu Jul 26 2018

### bug

- [bug]

  Fixed issue in the `CacheRegion.get_or_create_multi()` method which was erroneously considering the cached value as the timestamp field if the `CacheRegion.invalidate()` method had ben used, usually causing a `TypeError` to occur, or in less frequent cases an invalid result for whether or not the cached value was invalid, leading to excessive caching or regeneration. The issue was a regression caused by an implementation issue in the pluggable invalidation feature added in #38.

  References: #128

## 0.6.6

Released: Wed Jun 27 2018

### feature

- [feature]

  Added method `CacheRegion.actual_backend` which calculates and caches the actual backend for the region, which may be abstracted by the use of one or more `ProxyBackend` subclasses.

  References: #123

### bug

- [bug]

  Fixed a condition in the `Lock` where the “get” function could be called a second time unnecessarily, when returning an existing, expired value from the cache.

  References: #122

## 0.6.5

Released: Mon Mar 5 2018

### bug

- [bug]

  Fixed import issue for Python 3.7 where several variables named “async” were, leading to syntax errors. Pull request courtesy Brian Sheldon.

  References: #119

## 0.6.4

Released: Mon Jun 26, 2017

### bug

- [bug]

  The method `Region.get_or_create_multi()` will not pass to the cache backend if no values are ultimately to be stored, based on the use of the `Region.get_or_create_multi.should_cache_fn` function. This empty dictionary is unnecessary and can cause API problems for backends like that of Redis. Pull request courtesy Tobias Sauerwein.

- [bug]

  The `api.NO_VALUE` constant now has a fixed `__repr__()` output, so that scenarios where this constant’s string value ends up being used as a cache key do not create multiple values. Pull request courtesy Paul Brown.

- [bug]

  A new exception class `exception.PluginNotFound` is now raised when a particular cache plugin class cannot be located either as a setuptools entrypoint or as a registered backend. Previously, a plain `Exception` was thrown. Pull request courtesy Jamie Lennox.

## 0.6.3

Released: Thu May 18, 2017

### feature

- [feature]

  Added `replace_existing_backend` to `CacheRegion.configure_from_config()`. Pull request courtesy Daniel Kraus.

## 0.6.2

Released: Tue Aug 16 2016

### feature

- [feature]

  Added a new system to allow custom plugins specific to the issue of “invalidate the entire region”, using a new base class `RegionInvalidationStrategy`. As there are many potential strategies to this (special backend function, storing special keys, etc.) the mechanism for both soft and hard invalidation is now customizable. New approaches to region invalidation can be contributed as documented recipes. Pull request courtesy Alexander Makarov.

  References: #38

- [feature]

  Added a new cache key generator `kwarg_function_key_generator()`, which takes keyword arguments as well as positional arguments into account when forming the cache key.

  References: #43

### bug

- [bug]

  Restored some more util symbols that users may have been relying upon (although these were not necessarily intended as user-facing): `dogpile.cache.util.coerce_string_conf`, `dogpile.cache.util.KeyReentrantMutex`, `dogpile.cache.util.memoized_property`, `dogpile.cache.util.PluginLoader`, `dogpile.cache.util.to_list`.

## 0.6.1

Released: Mon Jun 6 2016

### bug

- [bug]

  Fixed imports for `dogpile.core` restoring `ReadWriteMutex` and `NameRegistry` into the base namespace, in addition to `dogpile.core.nameregistry` and `dogpile.core.readwrite_lock`.

  References: #99

## 0.6.0

Released: Mon Jun 6 2016

### feature

- [feature]

  The `dogpile.core` library has been rolled in as part of the `dogpile.cache` distribution. The configuration of the `dogpile` name as a namespace package is also removed from `dogpile.cache`. In order to allow existing installations of `dogpile.core` as a separate package to remain unaffected, the `.core` package has been retired within `dogpile.cache` directly; the `Lock` class is now available directly as `dogpile.Lock` and the additional `dogpile.core` constructs are under the `dogpile.util` namespace.

  Additionally, the long-deprecated `dogpile.core.Dogpile` and `dogpile.core.SyncReaderDogpile` classes have been removed.

  References: #91

### bug

- [bug]

  The Redis backend now creates a copy of the “arguments” dictionary passed to it, before popping values out of it. This prevents the given dictionary from losing its keys.

- [bug]

  Fixed bug in “null” backend where `NullLock` did not accept a flag for the `NullLock.acquire()` method, nor did it return a boolean value for “success”.

  References: #97

## 0.5.7

Released: Mon Oct 19 2015

### feature

- [feature]

  Added new parameter `GenericMemcachedBackend.lock_timeout`, used in conjunction with `GenericMemcachedBackend.distributed_lock`, will specify the timeout used when communicating to the `.add()` method of the memcached client. Pull request courtesy Frits Stegmann and Morgan Fainberg.

  References: #54, pull request 37

- [feature]

  Added a new flag `CacheRegion.configure.replace_existing_backend`, allows a region to have a new backend replace an existing one. Pull request courtesy hbccbh.

  References: #65, pull request 35

- [feature] [tests]

  Test suite now runs using py.test. Pull request courtesy John Anderson.

  References: pull request 33

### bug

- [bug] [redis]

  Repaired the `CacheRegion.get_multi()` method when used with a list of zero length against the redis backend.

  References: #74

## 0.5.6

Released: Mon Feb 2 2015

### feature

- [feature]

  Changed the pickle protocol for the file/DBM backend to `pickle.HIGHEST_PROTOCOL` when producing new pickles, to match that of the redis and memorypickle backends. Pull request courtesy anentropic.

  References: pull request 30

## 0.5.5

Released: Wed Jan 21 2015

### feature

- [feature]

  Added new arguments `CacheRegion.cache_on_arguments.function_key_generator` and `CacheRegion.cache_multi_on_arguments.function_multi_key_generator` which serve as per-decorator replacements for the region-wide `CacheRegion.function_key_generator` and `CacheRegion.function_multi_key_generator` parameters, respectively, so that custom key production schemes can be applied on a per-function basis within one region. Pull request courtesy Hongbin Lu.

  References: pull request 26

### bug

- [bug]

  Fixed bug where sending -1 for the `CacheRegion.get_or_create.expiration_time` parameter to `CacheRegion.get_or_create()` or `CacheRegion.get_or_create_multi()` would fail to honor the setting as “no expiration time”. Pull request courtesy Hongbin Lu.

  References: #71, pull request 25

- [bug]

  The `wrap` argument is now propagated when calling `CacheRegion.configure_from_config()`. Pull request courtesy Jonathan Vanasco.

  References: #41, pull request 28

- [bug]

  Fixed tests under py.test, which were importing a symbol from pytest itself `is_unittest` which has been removed.

## 0.5.4

Released: Sat Jun 14 2014

### feature

- [feature]

  Added new `NullBackend`, for testing and cache-disabling purposes. Pull request courtesy Wichert Akkerman.

  References: pull request 18

- [feature]

  Added new `RedisBackend.connection_pool` option on the Redis backend; this can be passed a `redis.ConnectionPool` instance directly. Pull request courtesy Masayuko.

  References: pull request 17

- [feature]

  Added new `RedisBackend.socket_timeout` option on the Redis backend. Pull request courtesy Saulius Menkevičius.

  References: pull request 16

- [feature]

  Added support for tests to run via py.test.

### bug

- [bug]

  Added missing Mako test dependency to setup.py. Pull request courtesy Wichert Akkerman.

  References: pull request 19

- [bug]

  Fixed bug where calling `CacheRegion.get_multi()` or `CacheRegion.set_multi()` with an empty list would cause failures based on backend. Pull request courtesy Wichert Akkerman.

  References: #58, pull request 20

- [bug]

  Repaired the entry point for Mako templates; the name of the entrypoint itself was wrong vs. what was in the docs, but beyond that the entrypoint would load the wrong module name. Pull request courtesy zoomorph.

  References: pull request 15

- [bug]

  The `coerce_string_conf()` function, which is used by `Region.configure_from_config()`, will now recognize floating point values when parsing conf strings and deliver them as such; this supports non-integer values such as Redis `lock_sleep`. Pullreq courtesy Jeff Dairiki.

  References: #57, pull request 13

## 0.5.3

Released: Wed Jan 8 2014

### feature

- [feature]

  Added a `get()` method to complement the `set()`, `invalidate()` and `refresh()` methods established on functions decorated by `CacheRegion.cache_on_arguments()` and `CacheRegion.cache_multi_on_arguments()`. Pullreq courtesy Eric Hanchrow.

  References: #55

- [feature]

  Added a new variant on `MemoryBackend`, `MemoryPickleBackend`. This backend applies `pickle.dumps()` and `pickle.loads()` to cached values upon set and get, so that similar copy-on-cache behavior as that of other backends is employed, guarding cached values against subsequent in-memory state changes. Pullreq courtesy Jonathan Vanasco.

  References: #51, pull request 11

### bug

- [bug]

  Fixed bug where the key_mangler would get in the way of usage of the async_creation_runner feature within the `Region.get_or_create()` method, by sending in the mangled key instead of the original key. The “mangled” key is only supposed to be exposed within the backend storage, not the creation function which sends the key back into the `Region.set()`, which does the mangling itself. Pull request courtesy Ryan Kolak.

  References: pull request 10

- [bug] [py3k]

  Fixed bug where the `Region.get_multi()` method wasn’t calling the backend correctly in Py3K (e.g. was passing a destructive `map()` object) which would cause this method to fail on the memcached backend.

- [bug]

  Fixed a format call in the redis backend which would otherwise fail on Python 2.6; courtesy Jeff Dairiki.

  References: pull request 9

## 0.5.2

Released: Fri Nov 15 2013

### feature

- [feature]

  Added a new argument `lock_factory` to the `DBMBackend` implementation. This allows for drop-in replacement of the default `FileLock` backend, which builds on `os.flock()` and only supports Unix platforms. A new abstract base `AbstractFileLock` has been added to provide a common base for custom lock implementations. The documentation points to an example thread-based rw lock which is now tested on Windows.

  References: #44

### bug

- [bug]

  Fixes to routines on Windows, including that default unit tests pass, and an adjustment to the “soft expiration” feature to ensure the expiration works given windows time.time() behavior.

- [bug]

  Added py2.6 compatibility for unsupported `total_seconds()` call in region.py

## 0.5.1

Released: Thu Oct 10 2013

### feature

- [feature]

  The `CacheRegion.invalidate()` method now supports an option `hard=True|False`. A “hard” invalidation, equivalent to the existing functionality of `CacheRegion.invalidate()`, means `CacheRegion.get_or_create()` will not return the “old” value at all, forcing all getters to regenerate or wait for a regeneration. “soft” invalidation means that getters can continue to return the old value until a new one is generated.

  References: #38

- [feature]

  New dogpile-specific exception classes have been added, so that issues like “region already configured”, “region unconfigured”, raise dogpile-specific exceptions. Other exception classes have been made more specific. Also added new accessor `CacheRegion.is_configured`. Pullreq courtesy Morgan Fainberg.

  References: #40

### bug

- [bug]

  Erroneously missed when the same change was made for `set()` in 0.5.0, the Redis backend now uses `pickle.HIGHEST_PROTOCOL` for the `set_multi()` method as well when producing pickles. Courtesy Łukasz Fidosz.

- [bug] [py3k] [redis]

  Fixed an errant `u''` causing incompatibility in Python3.2 in the Redis backend, courtesy Jimmey Mabey.

  References: #39

- [bug]

  The `util.coerce_string_conf()` method now correctly coerces negative integers and those with a leading + sign. This previously prevented configuring a `CacheRegion` with an `expiration_time` of `'-1'`. Courtesy David Beitey.

- [bug]

  The `refresh()` method on `CacheRegion.cache_multi_on_arguments()` now supports the `asdict` flag.

## 0.5.0

Released: Fri Jun 21 2013

### feature

- [feature]

  Now using the `Lock` included with the Python `redis` backend, which adds `lock_timeout` and `lock_sleep` arguments to the `RedisBackend`.

- [feature]

  Added new methods `CacheRegion.get_or_create_multi()` and `CacheRegion.cache_multi_on_arguments()`, which make use of the `CacheRegion.get_multi()` and similar functions to store and retrieve multiple keys at once while maintaining dogpile semantics for each.

  References: #33, #35

- [feature]

  Added a method `refresh()` to functions decorated by `CacheRegion.cache_on_arguments()` and `CacheRegion.cache_multi_on_arguments()`, to complement `invalidate()` and `set()`.

  References: #36

- [feature]

  `CacheRegion.configure()` accepts an optional `datetime.timedelta` object for the `expiration_time` argument as well as an integer, courtesy Jack Lutz.

  References: #13

- [feature]

  The `expiration_time` argument passed to `CacheRegion.cache_on_arguments()` may be a callable, to return a dynamic timeout value. Courtesy David Beitey.

  References: #20

- [feature]

  Added support for simple augmentation of existing backends using the `ProxyBackend` class. Thanks to Tim Hanus for the great effort with development, testing, and documentation.

  References: #26

- [feature]

  Full support for multivalue get/set/delete added, using `CacheRegion.get_multi()`, `CacheRegion.set_multi()`, `CacheRegion.delete_multi()`, courtesy Marcos Araujo Sobrinho.

  References: pull request 14

### bug

- [bug]

  The Redis backend now uses `pickle.HIGHEST_PROTOCOL` when producing pickles. Courtesy Lx Yu.

- [bug]

  `CacheRegion.cache_on_arguments()` now has a new argument `to_str`, defaults to `str()`. Can be replaced with `unicode()` or other functions to support caching of functions that accept non-unicode arguments. Initial patch courtesy Lx Yu.

- [bug]

  Fixed bug where the “name” parameter for `CacheRegion` was ignored entirely. Courtesy Wichert Akkerman.

  References: #27

### misc

- [misc]

  Source repository has been moved to git.

## 0.4.3

Released: Thu Apr 4 2013

### feature

- [feature]

  `CacheRegion.get_or_create()` and `CacheRegion.cache_on_arguments()` now accept a new argument `should_cache_fn`, receives the value returned by the “creator” and then returns True or False, where True means “cache plus return”, False means “return the value but don’t cache it.”

  References: pull request 13

### bug

- [bug]

  Added support for the `cache_timeout` Mako argument to the Mako plugin, which will pass the value to the `expiration_time` argument of `CacheRegion.get_or_create()`.

## 0.4.2

Released: Sat Jan 19 2013

### feature

- [feature]

  An “async creator” function can be specified to `CacheRegion` which allows the “creation” function to be called asynchronously or be subsituted for another asynchronous creation scheme. Courtesy Ralph Bean.

  References: pull request 10

## 0.4.1

Released: Sat Dec 15 2012

### feature

- [feature]

  The function decorated by `CacheRegion.cache_on_arguments()` now includes a `set()` method, in addition to the existing `invalidate()` method. Like `invalidate()`, it accepts a set of function arguments, but additionally accepts as the first positional argument a new value to place in the cache, to take the place of that key. Courtesy Antoine Bertin.

  References: pull request 9

- [feature]

  Redis backend now accepts optional “url” argument, will be passed to the new `StrictRedis.from_url()` method to determine connection info. Courtesy Jon Rosebaugh.

- [feature]

  Redis backend now accepts optional “password” argument. Courtesy Jon Rosebaugh.

- [feature]

  DBM backend has “fallback” when calling dbm.get() to instead use dictionary access + KeyError, in the case that the “gdbm” backend is used which does not include .get(). Courtesy Jon Rosebaugh.

### bug

- [bug]

  Fixed bug in DBM backend whereby if an error occurred during the “write” operation, the file lock, if enabled, would not be released, thereby deadlocking the app.

  References: #15

- [bug]

  The `util.function_key_generator()` used by the function decorator no longer coerces non-unicode arguments into a Python unicode object on Python 2.x; this causes failures on backends such as DBM which on Python 2.x apparently require bytestrings. The key_mangler is still needed if actual unicode arguments are being used by the decorated function, however.

  References: #12

## 0.4.0

Released: Tue Oct 30 2012

### bug

- [bug]

  Using dogpile.core 0.4.0 now, fixes a critical bug whereby dogpile pileup could occur on first value get across multiple processes, due to reliance upon a non-shared creation time. This is a dogpile.core issue.

  References: #1

- [bug]

  Fixed missing __future__ with_statement directive in region.py.

## 0.3.1

Released: Tue Sep 25 2012

### bug

- [bug]

  Fixed the mako_cache plugin which was not yet covered, and wasn’t implementing the mako plugin API correctly; fixed docs as well. Courtesy Ben Hayden.

- [bug]

  Fixed setup so that the tests/* directory isn’t yanked into the install. Courtesy Ben Hayden.

## 0.3.0

Released: Thu Jun 14 2012

### feature

- [feature]

  get() method now checks expiration time by default. Use ignore_expiration=True to bypass this.

- [feature]

  Added new invalidate() method. Sets the current timestamp as a minimum value that all retrieved values must be created after. Is honored by the get_or_create() and get() methods.

  References: #7

### bug

- [bug]

  Fixed bug whereby region.get() didn’t work if the value wasn’t present.

  References: #8

## 0.2.4

no release date

- [no_tags]

  Fixed py3k issue with config string coerce, courtesy Alexander Fedorov

## 0.2.3

Released: Wed May 16 2012

- [no_tags]

  support “min_compress_len” and “memcached_expire_time” with python-memcached backend. Tests courtesy Justin Azoff

  References: #3

- [no_tags]

  Add support for coercion of string config values to Python objects - ints, “false”, “true”, “None”.

  References: #4

- [no_tags]

  Added support to DBM file lock to allow reentrant access per key within a single thread, so that even though the DBM backend locks for the whole file, a creation function that calls upon a different key in the cache can still proceed.

  References: #5

- [no_tags]

  Fixed DBM glitch where multiple readers could be serialized.

- [no_tags]

  Adjust bmemcached backend to work with newly-repaired bmemcached calling API (see bmemcached ef206ed4473fec3b639e).

## 0.2.2

Released: Thu Apr 19 2012

- [no_tags]

  add Redis backend, courtesy Ollie Rutherfurd

## 0.2.1

Released: Sun Apr 15 2012

- [no_tags]

  move tests into tests/cache namespace

- [no_tags]

  py3k compatibility is in-place now, no 2to3 needed.

## 0.2.0

Released: Sat Apr 14 2012

- [no_tags]

  Based on dogpile.core now, to get the package namespace thing worked out.

## 0.1.1

Released: Tue Apr 10 2012

- [no_tags]

  Fixed the configure_from_config() method of region and backend which wasn’t working. Courtesy Christian Klinger.

## 0.1.0

Released: Sun Apr 08 2012

- [no_tags]

  Initial release.

- [no_tags]

  Includes a pylibmc backend and a plain dictionary backend.