146 lines
4.4 KiB
Text
146 lines
4.4 KiB
Text
.. default-role:: literal
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Local statuses and global setting
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=====================================
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Available configuration statuses
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----------------------------------
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.. currentmodule:: tiramisu
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The configuration's status lives in an :class:`setting.Setting()` object.
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This configuration status corresponds to specific attributes or bunch of
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attributes that can be accessed together with some `setting.Setting`
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method:
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**read write status**
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The configuration can be accessed by `__get__` and `__set__`
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properties, except for the `hidden` configuration options but, yes, it is
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possible to modify a disabled option.
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To enable read-write status, call
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:class:`~config.CommonConfig.read_write()` on the config.
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**read only status**
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The whole configuration is `frozen`, that is modifiying a value is
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forbidden. We can access to a configuration option only with the
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`__getattr__` property.
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The configuration has not an access to the hidden options
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but can read the disabled options.
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To enable read only status, call :class:`~config.SubConfig.read_only()` on
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the config.
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.. csv-table:: **Configuration's statuses summary**
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:header: " ", "Hidden", "Disabled", "Mandatory"
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"read only status", `False`, `True`, `True`
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"read-write status", `True`, `False`, `False`
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.. _`frozenconfig`:
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Freezing a configuration
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---------------------------
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.. todo:: freeze at configuration level
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At the configuration level, `setting.Setting.freeze` freezes
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the whole configuration options.
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.. _`frozen`:
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It is possible to *freeze* a single :class:`option.Option()` object with
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:meth:`config.SubConfig.cfgimpl_get_settings()`. If you try to modify a frozen
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:option, it raises a `TypeError: trying to change a frozen option object`.
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To find out if an option `myoption` is frozen, just make an assertion on the
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settings like that::
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'frozen' in cfg.cfgimpl_get_settings()[myoption]
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Moreover, frozen option can return their default values if
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`option.Option.force_default()` is called on this option.
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Restricted access to an `Option()`
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-----------------------------------
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.. currentmodule:: tiramisu.setting
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.. autoclass:: Property
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The `properties` attribute is in charge of the access rules' option's value.
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Configuration options access statuses are defined at configuration level
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that corresponds to the `option.Option()`'s `properties` attribute,
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for example: hidden, disabled.
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Use the pythonic way to know if a property is there::
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'hidden' in c.cfgimpl_get_settings()
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'frozen' in c.cfgimpl_get_settings()[opt]
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To access to the global settings::
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cfg.cfgimpl_get_settings()
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cfg.cfgimpl_get_settings()[option1]
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to add, or suppress a global property::
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cfg.cfgimpl_get_settings()[option1].append('hidden')
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cfg.cfgimpl_get_settings()[option1].remove('hidden')
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to activate, deactivate properties::
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cfg.cfgimpl_get_settings().append('hidden')
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cfg.cfgimpl_get_settings().remove('hidden')
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Value owners
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-------------
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Every configuration option has a **owner**. When the option is instanciated,
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the owner is :obj:`setting.owners.default` because a default value has been set
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(including `None`, wich means that no value has been set yet).
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.. method:: config.CommonConfig.getowner()
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This method can retrieve an Option's owner.
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- At the instance of the `Config` object, the value owner is
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:obj:`setting.owners.default` because
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the default values are set at the instance of the configuration option
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object,
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- at the modification of an option, the owner is `owners.default`, (which is
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:obj:`owners.user`)
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Special behaviors for an option
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---------------------------------
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**mandatory**
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A mandatory option shall return a value. If a value, or a default value
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has not been set, a error is raised.
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**has a callback**
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This means that it is a calculated value and therefore automatically
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protected it cannot be modified by attribute access.
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**force_store_value**
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if the configuration option has a default value, the default is
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returned, otherwise the value is calculated.
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Its inner state is represented by `option.Option.force_default()`
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Configuration options have default values that are stored in the
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`Option()` object itself. Default values, the `default`, can be set in
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various ways.
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If a default value is modified by overriding it, not only the value of
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the option resets to the default that is proposed, but the owner is
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modified too, it is reseted to `owners.default`.
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