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Configuration settings: customize applications towards the users' needs. It fulfills following properties:
- It is provided by the execution environment.
- It can be changed by the maintainer, user, or system administrator of the software.
- It consists of a key name, a configuration value, and potentially metadata.
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A configuration file: is a file containing configuration settings.
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Configuration storage: makes configuration settings persistent. The application will read the configuration at every start from the configuration storage, but it is only stored if a user changes settings.
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Key databases: are used for configuration storages because of these constraints. They can do fast key lookups and the keys can be structured hierarchically by defining separators in the key names.
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Global key database: provides global access to all configuration storages of all applications in a system. Abbreviated as
KDB
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LibElektra: is a set of libraries to access configuration parameters in a global, hierarchical key database.
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SpecElektra: is a specification language that allows us to describe the content of the global key database.
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Elektra: is a framework consisting of LibElektra, SpecElektra, and a collection of tools.
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To elektrify an application: to change the application so that it uses LibElektra afterwards.
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Elektra Initiative: is a community that develops LibElektra, expands SpecElektra, improves Elektra's tooling and helps to elektrify applications.
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Option, more specifically Command-line option: is a special argument passed on the command-line. Short options are single characters prefixed with '-'; Long options are arbitrarily long and start with '--'.
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Backends: A collection of plugins to be mounted. A backend typically is responsible to read and write a configuration file.
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Bootstrapping: To read the mounting configuration and mount during
kdbOpen()
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Cascading: To consider multiple places to look for a key.
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Contracts: Contracts state the purpose, functionality and requirements of plugins.
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Mounting: To persistently and permanently include a backend in the global key database. The mountpoint is the key where the backend is mounted to. All keys of the backend are below that key.
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Key name: All keys in the KDB have a name. This name is the keys unique identifier and follows a particular structure. For more information take look at the keyname documentation.
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Key name part: Key names consist of a series parts (and a namespace).
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Key base name: The last part of a key name.
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Key dir name: The key name obtained by omitting both namespace and base name from a key name.
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Namespaces: Allow us to have multiple keys for the same purpose and otherwise the same key name.
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Plugins: The unit of implementation for a feature.
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Metadata: Allows us to describe configuration settings.
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Sync Flag: Marks keys that were changed and need to be written out to disc.
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Null Keys, Null Values: The absence of keys or values.
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pop: used in
ksPop()
and @ref KDB_O_POP means to remove a key from a keyset. -
delete: or abbr. del, used in
keyDel()
,ksDel()
and @ref KDB_O_DEL means to free a key or keyset. The memory can be used for something else afterwards. -
remove: means that the key-value information in the physical database will be removed permanently.