config_decorator package

Submodules

config_decorator.config_decorator module

Class @decorator for defining exquisite settings configurations.

Concepts

A configurable setting is some value in an application that can be “globally” set.

Most often, a configurable setting is used so that an end user can change the behavior of an application. All settings might be saved to a file on disk and read whenever the application starts. In this case, the collection of configurable settings might simply be called the “user options”.

But you could also use configurable settings to decouple code. For example, rather than two objects sharing values by interacting with one another, they could instead share values using a common settings configuration. Then the two objects only need to know common key names, and not about each other.

At its core, each setting has a name (its key), and a value. The value could be a default value specified in code, or it could be a value somehow specified by the user, such as from the command line, or from an environment variable, or from a file saved on disk.

Furthermore, each setting has a description (some helpful text), a type (int, bool, list, etc.), an optional validation function, and other qualities (see more in the key_chained_val module).

Multiple settings can be organized into hierarchically-related groups, or sections (as represented by the ConfigDecorator class, but generated using the @section decorator).

In addition to settings, each section may also contain sections (or, more aptly, subsections).

You can think of the complete hierarchical collection of sections and their settings as a settings configuration, or as the user options.

Each section of a settings configuration is represented by a ConfigDecorator instance. The settings themselves are each represented by a KeyChainedVal instance.

Typical usage

To create a settings configuration, use the @section decorator once to designate the root object of the settings configuration. The decorated class is then used to decorate each subsection class, as well as each settings method. (And then the subsection classes can be used to decorate sub-subsections and their settings, and so on.)

For example:

def generate_config(self):
    '''An example setting configuration generator.'''

    @section(None)
    class RootSection(object):
        pass

    @RootSection.section('foo')
    class RootSectionFoo(object):
        def __init__(self):
            pass

    @RootSection.section('bar')
    class RootSectionBar(object):
        def __init__(self):
            pass

    @RootSectionBar.section('baz')
    class BarSubsectionBaz(object):
        def __init__(self):
            pass

        @property
        @RootSectionBar.setting(
            "An example setting.",
        )
        def bat(self):
            return 'Ta-Da!'

    return RootSection

In the example above, there are two root sections defined, “foo” and “bar”. And there’s one setting defined in the “bar.baz” subsection. You could run, e.g.,:

>>> cfg = generate_config()
>>> cfg.bar.baz.bat
'Ta-Da!'

Note that because of how decorators operate on a class (they execute after the class is defined), the settings defined in a class definition must be decoratored using that class’s parent section. (In the previous example, @RootSectionBar.setting was used inside BarSubsectionBaz.)

Important

You cannot access the decorated user class using its name.
- The @section decorator wraps the class definition in a ConfigDecorator instance, and it returns that object.
- So in the previous example, RootSection is a ConfigDecorator instance and not a class object. I.e., you cannot call obj = RootSection().

class config_decorator.config_decorator.ConfigDecorator(cls, cls_or_name, parent=None, default_value_type=None, default_allow_none=False)[source]

Bases: object

Represents one section of a hierarchical settings configuration.

A settings configuration is a collection of user-settable key-value settings grouped and organized into a tree-like graph of sections.

A settings configuration has one root section, which may have any number of subsections and settings therein. Each subsection may also contain any number of subsections and settings.

Each ConfigDecorator wraps a user class that defines the settings in that section. To add subsections to a section, use the section object’s ConfigDecorator.section() decorator. One or more classes are defined and decorated this way to build a hierarchical settings configuration.

Important

Users of this library do not call ConfigDecorator() directly.

Rather, object creation is handled by the config_decorator.section() and ConfigDecorator.section() decorators.

Parameters:

cls – The class being decorated.
cls_or_name – The section name to use in the settings configuration.
parent – A reference to the parent section (a ConfigDecorator object), or None for the root section.
default_value_type – Default value_type for unstructured @settings (KeyChainedValue objects) under this section (e.g., where the config does not define any specific key names, but it expects to read those key names from user’s config). Typically used for unstructured list config.
default_allow_none – Default allow_none for unstructured @settings (KeyChainedValue objects) under this section. Pairs well with default_value_type.

_innercls: The class object that was decorated (whose name now references a ConfigDecorator instance, and not the class object that was defined.

_innerobj: An instance of the class object that was decorated.

_parent: A reference to the parent ConfigDecorator section, or None for the root section.

_kv_cache: An ordered dict of settings defined by the class, used internally when build the settings configuration (i.e., used internally while sourcing Python code).

_key_vals: This section’s settings, stored as a dict (setting name ⇒ config_decorator.key_chained_val.KeyChainedValue object).

_sections: An ordered dict of subsections (section name ⇒ ConfigDecorator object).

_name: The section name, specified in the decorator, or inferred from the class name.

SEP = '.': Separator character used to (un)flatten section.subsection.settings paths.

apply_items(config, **kwargs)[source]

Prepares the passed dict with the config, stringifying values by default.

Args: Same as for _prepare_dict().

as_dict(**kwargs)[source]

Returns a new dict representing the configuration settings tree.

Args: Same as for _prepare_dict().

property asobj

Returns a representation of the section that can be accessed like an object.

Returns:

An object that overrides __getattr__ to find the section or setting in the current section that has the given name.

The object also has a magic _ method, if you want to use dot-notation to get at a subsection, but then want access to the actual section object.

classmethod create_root_for_section(section_name, section_cdec)[source]: Creates a new ConfigDecorator as root of the passed instance.

del_not_persisted(config_obj)[source]: Removes entries from config_obj without a value from the “config” source.

find_all(parts, skip_sections=False)[source]

Returns all matching sections or settings.

Parameters:

parts –
A list of strings used to find matching sections and settings.
- If empty, the currect section is returned (the identify function).
- If just one name is specified in “parts”, all sections and settings that match that name are assembled and returned (by performing a breadth-first search of the current section and its subsections).
- If more than one name is specified, the leading names form the path to the section to search; and then any section or setting in that section matching the final name in “parts” is returned.
skip_sections – If True, do not include section objects in the results.

Returns:

A list of matching sections and settings.

find_root()[source]: Returns the topmost section object, that which has no parent.

find_setting(parts)[source]

Returns the setting with the given path and name.

Parameters:: parts – A list of strings indicating the section names and setting name.
Returns:: The indentified setting, or None if no setting found.

forget_config_values()[source]

Visits every setting and removes the value from the “config” source.

Unless a setting’s value can be gleaned from an environment variable, or was parsed from the command line, or was forceable set by the code, calling this method will effectively set the value back to its default.

get_section_or_create_new(section_name)[source]

items()[source]: Returns dict of section names → subsections, and setting names → values.

keys()[source]: Returns a list of the top-level section and settings names.

section(name, default_value_type=None, default_allow_none=False)[source]

Class decorator used to create subsections.

For instance:

@section(None)
class RootSection(object):
    pass

@RootSection.section('My Subsection')
class MySubsection(object):
    pass

@MySubsection.section('A Grandsubsection')
class AGrandsubsection(object):
    pass

Parameters:: name – The name of the subsection.
Returns:: A ConfigDecorator instance.

See config_decorator.config_decorator.section() section() for a more complete explanation.

section_path(sep=None, _parts=None)[source]

Returns a flattened canonicalized representation of the complete section path.

Parameters:

sep – The separator character to use, defaults to ConfigDecorator.SEP.
_parts – Used internally on recursive calls to this function.

Returns:

The “path” to this section, as derived from the name of the root section on downward to this section, using the separator character between each successive section’s name.

set_section(section_name, sub_dcor)[source]

Assigns the passed ConfigDecorator to the section key named.

# NOTE: This method is clobbery.

setdefault(*args)[source]

Ensures the indicated setting exists, much like dict.setdefault.

Parameters:: args – one or more arguments indicating the section path and setting name, and one final argument indicating the default setting value to use.
Returns:: The setting value (the existing value if already set; otherwise the new default value, which is also the last item in *args).

setting(message=None, **kwargs)[source]

Method decorator used to create individual settings in a configuration section.

For instance:

...

@RootSection.section('My Subsection')
class MySubsection(object):
    @property
    @RootSection.setting(
        "An example setting.",
        name="my-setting"
    )
    def my_setting(self):
        return 'My Setting's Default Value'

update(other, errors_ok=False)[source]: Alias to update_gross().

update_gross(other, errors_ok=False)[source]

Consumes all values from a dict, creating new sections and settings as necessary.

Parameters:: other – The dict whose contents will be consumed.

See also update_known(), which does not add unknown values.

This method is less discerning. It grabs everything from other and shoves it in the ConfigDecorator object, creating section and setting objects as necessary.

You might find this useful if your app handles arbitrary config. In this case, the application cannot define the config in the code, because it lets the user use whatever names they want. In that case, load the config into a dict (say, using ConfigObj), and then pass that dictionary to this method.

update_known(config, errors_ok=False)[source]

Updates existing settings values from a given dictionary.

Parameters:: config – A dict whose key-values will be used to set settings “config” value sources accordingly.
Returns:: A dict containing any unknown key-values from “config” that did not correspond to a known section or setting.

values()[source]: Returns a list of sub-section branches and top-level settings values.

walk(visitor)[source]

Visits every section and runs the passed method on every setting.

Parameters:: visitor – Function to run on each setting. Will be passed a reference to the ConfigDecorator, and a reference to the config_decorator.key_chained_val.KeyChainedValue object.

config_decorator.key_chained_val module

Class to manage key-value settings.

class config_decorator.key_chained_val.KeyChainedValue(section=None, name='', default_f=None, value_type=None, allow_none=False, choices='', doc='', ephemeral=False, hidden=False, validate=None, conform=None, recover=None)[source]

Bases: object

Represents one setting of a section of a hierarchical settings configuration.

__init__(section=None, name='', default_f=None, value_type=None, allow_none=False, choices='', doc='', ephemeral=False, hidden=False, validate=None, conform=None, recover=None)[source]

Inits a KeyChainedValue object.

Do not create these objects directly, but instead use the config_decorator.config_decorator.ConfigDecorator.settings() decorator.

Except for section, the following arguments may be specified in the decorator call.

For instance:

@property
@RootSectionBar.setting(
    "An example setting.",
    name='foo-bar',
    value_type=bool,
    hidden=True,
    # etc.
)
def foo_bar(self):
    return 'True'

Parameters:

section – A reference to the section that contains this setting (a config_decorator.config_decorator.ConfigDecorator).
name – The setting name, either inferred from the class method that is decorated, or specified explicitly.
default_f – A method (i.e., the decorated class method) that generates the default setting value.
value_type – The setting type, either inferred from the type of the default value, or explicitly indicated. It’s often useful to explicitly set bool types so that the default function can return a 'True' or 'False' string.
allow_none – True if the value is allowed to be None, otherwise when the value is set, it will be passed to the type converted, which might fail on None, or produce unexpected results (such as converting None to 'None').
choices – A optional list of valid values, used to validate input when setting the value.
doc – Helpful text about the setting, which your application could use to show the user. The doc can specified as a keyword argument, or as the first positional argument to the decorator.
ephemeral – If True, the setting is meant not to be persisted between sessions (e.g., ephemeral settings are excluded on a call to config_decorator.config_decorator.ConfigDecorator.apply_items() .)
hidden – If True, the setting is excluded from an output operation if the value is the same as the setting’s default value.
validate – An optional function to validate the value when set from user input. If the validate function returns a falsey value, setting the value raises ValueError.
conform – If set, function used to translate config value to the value used internally. Useful for log levels, datetime, etc.
recover – If set, function used to convert internal value back to storable value. Useful to covert log level back to name, etc.

property asobj: Returns self, behaving as identify function (need to quack like ConfigDecorator).

property default: Returns the default setting value.

property doc: Returns the setting help text.

property ephemeral: Returns the ephemeral state.

find_root()[source]: Returns the topmost section object.

forget_config_value()[source]: Removes the “config” setting value set by the value_from_config() setter.

property hidden: Returns the hidden state.

property name: Returns the setting name.

property persisted: Returns True if the setting value was set via value_from_config().

property source

Returns the setting value source.

Returns:

The name of the highest priority source, as determined by the order of this list:

If the setting value was forced, by a call to the value_from_forced() setter, the value ‘forced’ is returned.
If the setting value was read from a command line argument, by a call to the value_from_cliarg() setter, the value ‘cliarg’ is returned.
If the setting value was read from an environment variable, by a call to the value_from_envvar() setter, the value ‘envvar’ is returned.
If the setting value was read from the dictionary source, by a call to the value() or value_from_config() setters, the value ‘config’ is returned.
Finally, if a value was not obtained from any of the above sources, the value ‘default’ is returned.

property value

Returns the setting value read from the highest priority source.

Returns:

The setting value from the highest priority source, as determined by the order of this list:

If the setting value was forced, by a call to the value_from_forced() setter, that value is returned.
If the setting value was read from a command line argument, by a call to the value_from_cliarg() setter, that value is returned.
If the setting value was read from an environment variable, by a call to the value_from_envvar() setter, that value is returned.
If the setting value was read from the dictionary source, by a call to the value() or value_from_config() setters, that value is returned.
Finally, if a value was not obtained from any of the above sources, the default value is returned.

property value_from_cliarg: Returns the “cliarg” setting value.

property value_from_config: Returns the “config” setting value.

property value_from_default: Returns the conformed default value.

property value_from_envvar

Returns the “envvar” setting value, sourced from the environment when called.

A name derived from a special prefix, the section path, and the setting name is used to look for an environment variable of the same name.

For example, consider that an application use the prefix “CFGDEC_”, and the setting is under a subsection called “pokey” which is under a topmost section called “hokey”. If the setting is named “foot”, then the environment variable would be named, “CFGDEC_HOKEY_POKEY_FOOT”.

property value_from_forced: Returns the “forced” setting value.

property value_unmutated: Returns the storable config value, generally just the stringified value.

walk(visitor)[source]

warn_if_no_envvar_prefix()[source]

config_decorator.slug_name_util module

Real powerful stuff.

config_decorator.slug_name_util.train2snakecase(name)[source]

Module contents

Root module package-level alias to config_decorator.config_decorator.section().

So you can call, e.g.,

from config_decorator import section

instead of

from config_decorator.config_decorator import section

class config_decorator.ConfigDecorator(cls, cls_or_name, parent=None, default_value_type=None, default_allow_none=False)[source]

Bases: object

Represents one section of a hierarchical settings configuration.

A settings configuration is a collection of user-settable key-value settings grouped and organized into a tree-like graph of sections.

A settings configuration has one root section, which may have any number of subsections and settings therein. Each subsection may also contain any number of subsections and settings.

Each ConfigDecorator wraps a user class that defines the settings in that section. To add subsections to a section, use the section object’s ConfigDecorator.section() decorator. One or more classes are defined and decorated this way to build a hierarchical settings configuration.

Important

Users of this library do not call ConfigDecorator() directly.

Rather, object creation is handled by the config_decorator.section() and ConfigDecorator.section() decorators.

Parameters:

cls – The class being decorated.
cls_or_name – The section name to use in the settings configuration.
parent – A reference to the parent section (a ConfigDecorator object), or None for the root section.
default_value_type – Default value_type for unstructured @settings (KeyChainedValue objects) under this section (e.g., where the config does not define any specific key names, but it expects to read those key names from user’s config). Typically used for unstructured list config.
default_allow_none – Default allow_none for unstructured @settings (KeyChainedValue objects) under this section. Pairs well with default_value_type.

_innercls: The class object that was decorated (whose name now references a ConfigDecorator instance, and not the class object that was defined.

_innerobj: An instance of the class object that was decorated.

_parent: A reference to the parent ConfigDecorator section, or None for the root section.

_kv_cache: An ordered dict of settings defined by the class, used internally when build the settings configuration (i.e., used internally while sourcing Python code).

_key_vals: This section’s settings, stored as a dict (setting name ⇒ config_decorator.key_chained_val.KeyChainedValue object).

_sections: An ordered dict of subsections (section name ⇒ ConfigDecorator object).

_name: The section name, specified in the decorator, or inferred from the class name.

SEP = '.': Separator character used to (un)flatten section.subsection.settings paths.

apply_items(config, **kwargs)[source]

Prepares the passed dict with the config, stringifying values by default.

Args: Same as for _prepare_dict().

as_dict(**kwargs)[source]

Returns a new dict representing the configuration settings tree.

Args: Same as for _prepare_dict().

property asobj

Returns a representation of the section that can be accessed like an object.

Returns:

An object that overrides __getattr__ to find the section or setting in the current section that has the given name.

The object also has a magic _ method, if you want to use dot-notation to get at a subsection, but then want access to the actual section object.

classmethod create_root_for_section(section_name, section_cdec)[source]: Creates a new ConfigDecorator as root of the passed instance.

del_not_persisted(config_obj)[source]: Removes entries from config_obj without a value from the “config” source.

find_all(parts, skip_sections=False)[source]

Returns all matching sections or settings.

Parameters:

parts –
A list of strings used to find matching sections and settings.
- If empty, the currect section is returned (the identify function).
- If just one name is specified in “parts”, all sections and settings that match that name are assembled and returned (by performing a breadth-first search of the current section and its subsections).
- If more than one name is specified, the leading names form the path to the section to search; and then any section or setting in that section matching the final name in “parts” is returned.
skip_sections – If True, do not include section objects in the results.

Returns:

A list of matching sections and settings.

find_root()[source]: Returns the topmost section object, that which has no parent.

find_setting(parts)[source]

Returns the setting with the given path and name.

Parameters:: parts – A list of strings indicating the section names and setting name.
Returns:: The indentified setting, or None if no setting found.

forget_config_values()[source]

Visits every setting and removes the value from the “config” source.

Unless a setting’s value can be gleaned from an environment variable, or was parsed from the command line, or was forceable set by the code, calling this method will effectively set the value back to its default.

get_section_or_create_new(section_name)[source]

items()[source]: Returns dict of section names → subsections, and setting names → values.

keys()[source]: Returns a list of the top-level section and settings names.

section(name, default_value_type=None, default_allow_none=False)[source]

Class decorator used to create subsections.

For instance:

@section(None)
class RootSection(object):
    pass

@RootSection.section('My Subsection')
class MySubsection(object):
    pass

@MySubsection.section('A Grandsubsection')
class AGrandsubsection(object):
    pass

Parameters:: name – The name of the subsection.
Returns:: A ConfigDecorator instance.

See config_decorator.config_decorator.section() section() for a more complete explanation.

section_path(sep=None, _parts=None)[source]

Returns a flattened canonicalized representation of the complete section path.

Parameters:

sep – The separator character to use, defaults to ConfigDecorator.SEP.
_parts – Used internally on recursive calls to this function.

Returns:

The “path” to this section, as derived from the name of the root section on downward to this section, using the separator character between each successive section’s name.

set_section(section_name, sub_dcor)[source]

Assigns the passed ConfigDecorator to the section key named.

# NOTE: This method is clobbery.

setdefault(*args)[source]

Ensures the indicated setting exists, much like dict.setdefault.

Parameters:: args – one or more arguments indicating the section path and setting name, and one final argument indicating the default setting value to use.
Returns:: The setting value (the existing value if already set; otherwise the new default value, which is also the last item in *args).

setting(message=None, **kwargs)[source]

Method decorator used to create individual settings in a configuration section.

For instance:

...

@RootSection.section('My Subsection')
class MySubsection(object):
    @property
    @RootSection.setting(
        "An example setting.",
        name="my-setting"
    )
    def my_setting(self):
        return 'My Setting's Default Value'

update(other, errors_ok=False)[source]: Alias to update_gross().

update_gross(other, errors_ok=False)[source]

Consumes all values from a dict, creating new sections and settings as necessary.

Parameters:: other – The dict whose contents will be consumed.

See also update_known(), which does not add unknown values.

This method is less discerning. It grabs everything from other and shoves it in the ConfigDecorator object, creating section and setting objects as necessary.

You might find this useful if your app handles arbitrary config. In this case, the application cannot define the config in the code, because it lets the user use whatever names they want. In that case, load the config into a dict (say, using ConfigObj), and then pass that dictionary to this method.

update_known(config, errors_ok=False)[source]

Updates existing settings values from a given dictionary.

Parameters:: config – A dict whose key-values will be used to set settings “config” value sources accordingly.
Returns:: A dict containing any unknown key-values from “config” that did not correspond to a known section or setting.

values()[source]: Returns a list of sub-section branches and top-level settings values.

walk(visitor)[source]

Visits every section and runs the passed method on every setting.

Parameters:: visitor – Function to run on each setting. Will be passed a reference to the ConfigDecorator, and a reference to the config_decorator.key_chained_val.KeyChainedValue object.

class config_decorator.KeyChainedValue(section=None, name='', default_f=None, value_type=None, allow_none=False, choices='', doc='', ephemeral=False, hidden=False, validate=None, conform=None, recover=None)[source]

Bases: object

Represents one setting of a section of a hierarchical settings configuration.

__init__(section=None, name='', default_f=None, value_type=None, allow_none=False, choices='', doc='', ephemeral=False, hidden=False, validate=None, conform=None, recover=None)[source]

Inits a KeyChainedValue object.

Do not create these objects directly, but instead use the config_decorator.config_decorator.ConfigDecorator.settings() decorator.

Except for section, the following arguments may be specified in the decorator call.

For instance:

@property
@RootSectionBar.setting(
    "An example setting.",
    name='foo-bar',
    value_type=bool,
    hidden=True,
    # etc.
)
def foo_bar(self):
    return 'True'

Parameters:

section – A reference to the section that contains this setting (a config_decorator.config_decorator.ConfigDecorator).
name – The setting name, either inferred from the class method that is decorated, or specified explicitly.
default_f – A method (i.e., the decorated class method) that generates the default setting value.
value_type – The setting type, either inferred from the type of the default value, or explicitly indicated. It’s often useful to explicitly set bool types so that the default function can return a 'True' or 'False' string.
allow_none – True if the value is allowed to be None, otherwise when the value is set, it will be passed to the type converted, which might fail on None, or produce unexpected results (such as converting None to 'None').
choices – A optional list of valid values, used to validate input when setting the value.
doc – Helpful text about the setting, which your application could use to show the user. The doc can specified as a keyword argument, or as the first positional argument to the decorator.
ephemeral – If True, the setting is meant not to be persisted between sessions (e.g., ephemeral settings are excluded on a call to config_decorator.config_decorator.ConfigDecorator.apply_items() .)
hidden – If True, the setting is excluded from an output operation if the value is the same as the setting’s default value.
validate – An optional function to validate the value when set from user input. If the validate function returns a falsey value, setting the value raises ValueError.
conform – If set, function used to translate config value to the value used internally. Useful for log levels, datetime, etc.
recover – If set, function used to convert internal value back to storable value. Useful to covert log level back to name, etc.

property asobj: Returns self, behaving as identify function (need to quack like ConfigDecorator).

property default: Returns the default setting value.

property doc: Returns the setting help text.

property ephemeral: Returns the ephemeral state.

find_root()[source]: Returns the topmost section object.

forget_config_value()[source]: Removes the “config” setting value set by the value_from_config() setter.

property hidden: Returns the hidden state.

property name: Returns the setting name.

property persisted: Returns True if the setting value was set via value_from_config().

property source

Returns the setting value source.

Returns:

The name of the highest priority source, as determined by the order of this list:

If the setting value was forced, by a call to the value_from_forced() setter, the value ‘forced’ is returned.
If the setting value was read from a command line argument, by a call to the value_from_cliarg() setter, the value ‘cliarg’ is returned.
If the setting value was read from an environment variable, by a call to the value_from_envvar() setter, the value ‘envvar’ is returned.
If the setting value was read from the dictionary source, by a call to the value() or value_from_config() setters, the value ‘config’ is returned.
Finally, if a value was not obtained from any of the above sources, the value ‘default’ is returned.

property value

Returns the setting value read from the highest priority source.

Returns:

The setting value from the highest priority source, as determined by the order of this list:

If the setting value was forced, by a call to the value_from_forced() setter, that value is returned.
If the setting value was read from a command line argument, by a call to the value_from_cliarg() setter, that value is returned.
If the setting value was read from an environment variable, by a call to the value_from_envvar() setter, that value is returned.
If the setting value was read from the dictionary source, by a call to the value() or value_from_config() setters, that value is returned.
Finally, if a value was not obtained from any of the above sources, the default value is returned.

property value_from_cliarg: Returns the “cliarg” setting value.

property value_from_config: Returns the “config” setting value.

property value_from_default: Returns the conformed default value.

property value_from_envvar

Returns the “envvar” setting value, sourced from the environment when called.

A name derived from a special prefix, the section path, and the setting name is used to look for an environment variable of the same name.

For example, consider that an application use the prefix “CFGDEC_”, and the setting is under a subsection called “pokey” which is under a topmost section called “hokey”. If the setting is named “foot”, then the environment variable would be named, “CFGDEC_HOKEY_POKEY_FOOT”.

property value_from_forced: Returns the “forced” setting value.

property value_unmutated: Returns the storable config value, generally just the stringified value.

walk(visitor)[source]

warn_if_no_envvar_prefix()[source]

config_decorator.section(cls_or_name, parent=None, default_value_type=None, default_allow_none=False)[source]

Class decorator used to indicate the root section of a settings configuration.

For instance:

@section(None)
class RootSection(object):
    pass

See Concepts for more help and usage examples.

Parameters:

cls_or_name – The section name, or the class being decorated if the decorator was not closed.
parent – When defining a subsection, the reference to the parent section (used internally by config_decorator.config_decorator.ConfigDecorator.section()).

Returns:

A ConfigDecorator instance.

Important

The name of the decorated class does not reference the defined user class, but rather it’s a config_decorator.config_decorator.ConfigDecorator instance.

To access the class definition that was decorated, use the return object’s _innercls attribute.

To access an instance of the decorated class, use _innerobj.