Resolve-DSCConfigurationData

Resolve-DSCConfigurationData resolves parameter, variable, and expression references in DSC configuration data.

Typical flow:

$merged = Merge-DSCConfigurationData -Template $service -Deployment $environment
$resolved = Resolve-DSCConfigurationData -ConfigurationData $merged

Expressions use an ARM-like syntax:

"[parameters('DatabasePrefix')]"
"[variables('ServiceDbPrefix')]"
"[concat(parameters('DatabasePrefix'), '_', parameters('ServiceDatabaseSegment'))]"

Parameter Example

This block shows all currently supported parameter properties.

@{
    Parameters = @{
        DatabasePrefix = @{
            Type = 'string'

            # Optional explicit value. If Value is present, it wins over DefaultValue.
            Value = 'SharePoint'

            # Used when Value is not present.
            DefaultValue = 'SharePoint'

            # If true, Value or DefaultValue must be present and not empty.
            Required = $true

            # Optional fixed set of valid values.
            AllowedValues = @(
                'SharePoint',
                'ProjectServer',
                'Search'
            )

            # Optional string length validation.
            MinLength = 2
            MaxLength = 32

            # Optional regex validation.
            Pattern = '^[A-Za-z][A-Za-z0-9_-]*$'

            # Metadata for later reporting/output tooling. The resolver does not mask values yet.
            Sensitive = $false

            # Emits a warning when the parameter is present.
            Deprecated = @{
                Message = @{
                    'de-DE' = 'Der Parameter [DatabasePrefix] ist veraltet. Verwende [SharePointDatabasePrefix].'
                    'en-US' = 'Parameter [DatabasePrefix] is deprecated. Use [SharePointDatabasePrefix].'
                }
            }

            Metadata = @{
                Description = @{
                    'de-DE' = 'Praefix fuer alle von der SharePoint-Farm angelegten Datenbanken.'
                    'en-US' = 'Prefix for all databases created by the SharePoint farm.'
                }
            }
        }
    }
}

Notes:

• Value wins over DefaultValue.
• Required, AllowedValues, MinLength, MaxLength, and Pattern are validated by the resolver.
• Sensitive is currently metadata only.
• Deprecated.Message can be a string or a localized hashtable.
• Optional string parameters can allow empty values with a pattern like '^$|^[A-Za-z][A-Za-z0-9_-]*$'.

Variable Example

Variables may reference parameters and other variables. Nested variable references are supported. Circular references are rejected.

@{
    Parameters = @{
        DatabasePrefix = @{
            Type = 'string'
            DefaultValue = 'SharePoint'
        }
        DomainLabel = @{
            Type = 'string'
            Value = 'LAN'
        }
        Landscape = @{
            Type = 'string'
            Value = 'Test'
            AllowedValues = @(
                'Prod',
                'Test'
            )
        }
        ServiceDatabaseSegment = @{
            Type = 'string'
            DefaultValue = 'Services'
        }
    }

    Variables = @{
        StageCode = "[if(equals(parameters('Landscape'), 'Test'), 'TST', 'PRD')]"
        DatabasePrefix = "[joinNotEmpty('_', parameters('DatabasePrefix'), parameters('DomainLabel'), variables('StageCode'))]"
        ServiceDbPrefix = "[joinNotEmpty('_', variables('DatabasePrefix'), parameters('ServiceDatabaseSegment'))]"
        ConfigDbName = "[joinNotEmpty('_', variables('DatabasePrefix'), 'Farm_Config')]"
    }
}

Example output:

StageCode       : TST
DatabasePrefix  : SharePoint_LAN_TST
ServiceDbPrefix : SharePoint_LAN_TST_Services
ConfigDbName    : SharePoint_LAN_TST_Farm_Config

Functions

References

"[parameters('DatabasePrefix')]"
"[variables('ServiceDbPrefix')]"

parameters(name) returns the effective parameter value. Value is used before DefaultValue.

variables(name) resolves another variable. Variables may reference other variables.

String Composition

"[concat('SharePoint', '_', 'Services')]"
# SharePoint_Services

"[format('{0}_{1}_{2}', parameters('DatabasePrefix'), parameters('DomainLabel'), parameters('Landscape'))]"
# SharePoint_LAN_Test

"[joinNotEmpty('_', parameters('DatabasePrefix'), parameters('DomainLabel'), '', 'Services')]"
# SharePoint_LAN_Services

"[defaultIfEmpty(parameters('DatabasePrefix'), 'SharePoint')]"
# SharePoint, when DatabasePrefix is empty

"[coalesce(parameters('CustomPrefix'), parameters('DatabasePrefix'), 'SharePoint')]"
# First non-empty value

Conditions And Boolean Logic

"[if(equals(parameters('Landscape'), 'Test'), 'TST', 'PRD')]"
# TST

"[equals(parameters('Landscape'), 'Test')]"
"[notEquals(parameters('Landscape'), 'Prod')]"
"[and(equals(parameters('Landscape'), 'Test'), not(empty(parameters('DatabasePrefix'))))]"
"[or(equals(parameters('Landscape'), 'Prod'), equals(parameters('Landscape'), 'Test'))]"
"[not(empty(parameters('DatabasePrefix')))]"

Case And Text

"[toLower('BGW-LAN')]"
# bgw-lan

"[toUpper('bgw-lan')]"
# BGW-LAN

"[trim('  SharePoint  ')]"
"[trimStart('  SharePoint')]"
"[trimEnd('SharePoint  ')]"

"[replace('BGW-LAN', '-', '_')]"
# BGW_LAN

"[substring('SharePoint', 5, 5)]"
# Point

"[indexOf('BGW', 1)]"
# G

firstIndexOf and lastIndexOf return the first or last function argument:

"[firstIndexOf('a', 'b', 'c')]"
# a

"[lastIndexOf('a', 'b', 'c')]"
# c

Name Cleanup

"[sanitizeName(' SharePoint LAN/Test DB ')]"
# SharePoint_LAN_Test_DB

"[sanitizeName(' SharePoint LAN/Test DB ', '-')]"
# SharePoint-LAN-Test-DB

"[normalizeSeparator('__SharePoint___LAN_Test__', '_')]"
# SharePoint_LAN_Test

"[prefixIfNotEmpty('LAN', 'BGW-')]"
# BGW-LAN

"[suffixIfNotEmpty('SharePoint', '_DB')]"
# SharePoint_DB

Collections

"[split(parameters('DomainFQDN'), '.')]"
# @('bgw-online', 'de')

"[join(split(parameters('DomainFQDN'), '.'), '_')]"
# bgw-online_de

"[first(split(parameters('DomainFQDN'), '.'))]"
# bgw-online

"[last(split(parameters('DomainFQDN'), '.'))]"
# de

"[take(split(parameters('DomainFQDN'), '.'), 1)]"
# @('bgw-online')

"[skip(split(parameters('DomainFQDN'), '.'), 1)]"
# @('de')

"[unique(split('SP.SP.SQL', '.'))]"
# @('SP', 'SQL')

"[sort(split('SQL.SP.APP', '.'))]"
# @('APP', 'SP', 'SQL')

Inspection

"[contains(parameters('DomainFQDN'), 'online')]"
# True

"[contains(split(parameters('DomainFQDN'), '.'), 'de')]"
# True

"[startsWith(parameters('DomainFQDN'), 'bgw')]"
# True

"[endsWith(parameters('DomainFQDN'), 'de')]"
# True

"[length(split(parameters('DomainFQDN'), '.'))]"
# 2

"[empty(parameters('OptionalValue'))]"
# True, when OptionalValue is empty

Padding

"[padLeft('1', 2, '0')]"
# 01

"[padRight('SP', 4, '0')]"
# SP00

Full Function List

• parameters(name)
• variables(name)
• concat(value1, value2, ...)
• format(formatString, value1, value2, ...)
• coalesce(value1, value2, ...)
• defaultIfEmpty(value, defaultValue)
• if(condition, trueValue, falseValue)
• equals(left, right)
• notEquals(left, right)
• and(value1, value2, ...)
• or(value1, value2, ...)
• not(value)
• toLower(value)
• toUpper(value)
• firstIndexOf(value1, value2, ...)
• lastIndexOf(value1, value2, ...)
• indexOf(value, index)
• substring(value, startIndex)
• substring(value, startIndex, length)
• replace(value, oldValue, newValue)
• sanitizeName(value)
• sanitizeName(value, separator)
• normalizeSeparator(value, separator)
• prefixIfNotEmpty(value, prefix)
• suffixIfNotEmpty(value, suffix)
• contains(value, search)
• startsWith(value, search)
• endsWith(value, search)
• split(value, separator)
• join(array, separator)
• joinNotEmpty(separator, value1, value2, ...)
• take(array, count)
• skip(array, count)
• first(array)
• last(array)
• unique(array)
• sort(array)
• trim(value)
• trimStart(value)
• trimEnd(value)
• padLeft(value, totalWidth)
• padLeft(value, totalWidth, paddingCharacter)
• padRight(value, totalWidth)
• padRight(value, totalWidth, paddingCharacter)
• length(value)
• empty(value)

Validation

Run the tests:

Invoke-Pester -Script '.\PowerShell\Resolve-DSCConfigurationData\.tests\Resolve-DSCConfigurationData.Tests.ps1'