.TH "doc_usecases_kdb_UC_validate_config_md" 3elektra "Thu Sep 7 2023" "Version 0.11.0" "Elektra" \" -*- nroff -*-
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.SH NAME
doc_usecases_kdb_UC_validate_config_md \- Use Case: Validating Configuration with Specification 
 
.SH "Summary"
.PP
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\fBScope:\fP \fClibelektra-kdb\fP, \fCspec\fP
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\fBLevel:\fP Developer Goal, User Goal
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\fBActors:\fP Elektra, Application, User
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\fBBrief:\fP After loading configuration, Application can assume the configuration is valid
.PP
.SH "Scenarios"
.PP
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\fBPrecondition:\fP
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A specification, defining how a valid configuration for Application looks like, exists\&.
.PP

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\fBMain success scenario:\fP
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\fBApplication loads configuration\fP During this process Elektra checks the configuration against the specification\&.
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Loading configuration results in no errors or warnings\&.
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Application knows configuration is valid\&.
.PP

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\fBAlternative scenario:\fP
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User requests to change configuration value via \fBApplication (e\&.g\&. `kdb`) stores configuration\fP\&. During this process Elektra checks the changed configuration against the specification\&.
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Elektra blocks the modification, if it violates the specification\&.
.PP

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\fBError scenario:\fP
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\fBApplication loads configuration\fP During this process Elektra checks the configuration against the specification\&.
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Loading configuration results in an error or warning\&.
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If a configuration is returned at all, Application knows the configuration may not be fully valid and can react accordingly\&.
.PP

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\fBPostcondition:\fP
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Configuration stored in the KDB and modified only via Elektra MUST be valid according to the specification\&.
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Configuration loaded by an application \fIwithout\fP error or warning MUST be valid according to the specification\&.
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Configuration loaded by an application \fIwith\fP error or warning MUST be valid according to the specification, except where an error or warning indicates otherwise\&.
.PP

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\fBNon-functional Constraints:\fP
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Because validation happens during \fBApplication loads configuration\fP, it MUST also be reasonably performant\&. Results MAY be cached to achieve this performance\&.
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Fixing an invalid configuration via Elektra MUST be possible\&. This SHOULD NOT require more changes than necessary, i\&.e\&., fixing invalid configuration MUST NOT be equivalent to 'delete everything and start again'\&. 
.PP

.PP