Cédric Krier
a99931c5c4
On distributed setup, the cache is not synchronized instantaneously so we can not use the cache if the record was modified by another process since the last synchronisation. issue9013 review262841002
63 lines
1.8 KiB
ReStructuredText
63 lines
1.8 KiB
ReStructuredText
.. _ref-cache:
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.. module:: trytond.cache
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=====
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Cache
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=====
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.. class:: Cache(name[, size_limit[, duration[, context]]])
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The class is used to cache values between server requests. The `name` should be
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unique and it's used to identify the cache. We usually use
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`<class_name>.<content_name>` to make it unique. The `size_limit` parameter can
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be used to limit the number of values cached and it has 1024 as the default
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value. The `duration` parameter defines how long a cached value stays valid
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but if it is not set the value remains valid until it is cleared. And the
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`context` parameter is used to indicate if the cache depends on the user
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context and is true by default. The cache is cleaned on :class:`Transaction`
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starts and resets on :class:`Transaction` commit or rollback.
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.. warning::
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As there is no deepcopy of the values cached, they must never be mutated
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after being set in or retrieved from the cache.
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..
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.. method:: get(key[, default])
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Retrieve the value of the key in the cache. If a `default` is specified it
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will be returned when the key is missing otherwise it will return `None`.
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.. method:: set(key, value)
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Sets the `value` of the `key` in the cache.
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.. method:: clear()
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Clears all the keys in the cache.
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.. classmethod:: sync(transaction)
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Synchronize cache instances using transaction.
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.. method:: sync_since(value)
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Return `True` if the last synchronization was done before `value`.
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.. classmethod:: commit(transaction)
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Apply cache changes from transaction.
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.. classmethod:: rollback(transaction)
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Remove cache changes from transaction.
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.. staticmethod:: drop(dbname)
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Drops all the caches for database `dbname`
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.. note::
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By default Tryton uses a MemoryCache, but this behaviour can be overridden
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by setting a fully qualified name of an alternative class defined in the
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configuration `class` of the `cache` section.
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..
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