Functions/Resolve-WhiskeyVariable.ps1
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function Resolve-WhiskeyVariable { <# .SYNOPSIS Replaces any variables in a string to their values. .DESCRIPTION The `Resolve-WhiskeyVariable` function replaces any variables in strings, arrays, or hashtables with their values. Variables have the format `$(VARIABLE_NAME)`. Variables are expanded in each item of an array. Variables are expanded in each value of a hashtable. If an array or hashtable contains an array or hashtable, variables are expanded in those objects as well, i.e. `Resolve-WhiskeyVariable` recursivelye expands variables in all arrays and hashtables. You can add variables to replace via the `Add-WhiskeyVariable` function. If a variable doesn't exist, environment variables are used. If a variable has the same name as an environment variable, the variable value is used instead of the environment variable's value. If no variable or environment variable is found, `Resolve-WhiskeyVariable` will write an error and return the origin string. See the `about_Whiskey_Variables` help topic for a list of variables. .EXAMPLE '$(COMPUTERNAME)' | Resolve-WhiskeyVariable Demonstrates that you can use environment variable as variables. In this case, `Resolve-WhiskeyVariable` would return the name of the current computer. .EXAMPLE @( '$(VARIABLE)', 4, @{ 'Key' = '$(VARIABLE') } ) | Resolve-WhiskeyVariable Demonstrates how to replace all the variables in an array. Any value of the array that isn't a string is ignored. Any hashtable in the array will have any variables in its values replaced. In this example, if the value of `VARIABLE` is 'Whiskey`, `Resolve-WhiskeyVariable` would return: @( 'Whiskey', 4, @{ Key = 'Whiskey' } ) .EXAMPLE @{ 'Key' = '$(Variable)'; 'Array' = @( '$(VARIABLE)', 4 ) 'Integer' = 4; } | Resolve-WhiskeyVariable Demonstrates that `Resolve-WhiskeyVariable` searches hashtable values and replaces any variables in any strings it finds. If the value of `VARIABLE` is set to `Whiskey`, then the code in this example would return: @{ 'Key' = 'Whiskey'; 'Array' = @( 'Whiskey', 4 ); 'Integer' = 4; } #> [CmdletBinding()] param( [Parameter(Mandatory=$true,ValueFromPipeline=$true)] [AllowNull()] [object] # The object on which to perform variable replacement/substitution. If the value is a string, all variables in the string are replaced with their values. # # If the value is an array, variable expansion is done on each item in the array. # # If the value is a hashtable, variable replcement is done on each value of the hashtable. # # Variable expansion is performed on any arrays and hashtables found in other arrays and hashtables, i.e. arrays and hashtables are searched recursively. $InputObject, [Parameter(Mandatory=$true)] [Whiskey.Context] # The context of the current build. Necessary to lookup any variables. $Context ) begin { Set-StrictMode -Version 'Latest' Use-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState $version = $Context.Version $buildInfo = $Context.BuildMetadata; $sem1Version = '' if( $version.SemVer1 ) { $sem1Version = '{0}.{1}.{2}' -f $version.SemVer1.Major,$version.SemVer1.Minor,$version.SemVer1.Patch } $sem2Version = '' if( $version.SemVer2 ) { $sem2Version = '{0}.{1}.{2}' -f $version.SemVer2.Major,$version.SemVer2.Minor,$version.SemVer2.Patch } $wellKnownVariables = @{ 'WHISKEY_BUILD_ID' = $buildInfo.BuildID; 'WHISKEY_BUILD_NUMBER' = $buildInfo.BuildNumber; 'WHISKEY_BUILD_ROOT' = $Context.BuildRoot; 'WHISKEY_BUILD_SERVER_NAME' = $buildInfo.BuildServer; 'WHISKEY_BUILD_STARTED_AT' = $Context.StartedAt; 'WHISKEY_BUILD_URI' = $buildInfo.BuildUri; 'WHISKEY_ENVIRONMENT' = $Context.Environment; 'WHISKEY_JOB_URI' = $buildInfo.JobUri; 'WHISKEY_MSBUILD_CONFIGURATION' = (Get-WhiskeyMSBuildConfiguration -Context $Context); 'WHISKEY_OUTPUT_DIRECTORY' = $Context.OutputDirectory; 'WHISKEY_PIPELINE_NAME' = $Context.PipelineName; 'WHISKEY_SCM_BRANCH' = $buildInfo.ScmBranch; 'WHISKEY_SCM_COMMIT_ID' = $buildInfo.ScmCommitID; 'WHISKEY_SCM_URI' = $buildInfo.ScmUri; 'WHISKEY_SEMVER1' = $version.SemVer1; 'WHISKEY_SEMVER1_VERSION' = $sem1Version; 'WHISKEY_SEMVER2' = $version.SemVer2; 'WHISKEY_SEMVER2_NO_BUILD_METADATA' = $version.SemVer2NoBuildMetadata; 'WHISKEY_SEMVER2_VERSION' = $sem2Version; 'WHISKEY_TASK_NAME' = $Context.TaskName; 'WHISKEY_VERSION' = $version.Version; } } process { Set-StrictMode -Version 'Latest' Use-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState if( $InputObject -eq $null ) { return $InputObject } if( (Get-Member -Name 'Keys' -InputObject $InputObject) ) { $newValues = @{ } $toRemove = New-Object 'Collections.Generic.List[string]' # Can't modify a collection while enumerating it. foreach( $key in $InputObject.Keys ) { $newKey = $key | Resolve-WhiskeyVariable -Context $Context if( $newKey -ne $key ) { $toRemove.Add($key) } $newValues[$newKey] = Resolve-WhiskeyVariable -Context $Context -InputObject $InputObject[$key] } foreach( $key in $newValues.Keys ) { $InputObject[$key] = $newValues[$key] } $toRemove | ForEach-Object { $InputObject.Remove($_) } | Out-Null return $InputObject } if( (Get-Member -Name 'Count' -InputObject $InputObject) ) { for( $idx = 0; $idx -lt $InputObject.Count; ++$idx ) { $InputObject[$idx] = Resolve-WhiskeyVariable -Context $Context -InputObject $InputObject[$idx] } return ,$InputObject } $startAt = 0 $haystack = $InputObject.ToString() do { # Parse the variable expression, everything between $( and ) $needleStart = $haystack.IndexOf('$(',$startAt) if( $needleStart -lt 0 ) { break } elseif( $needleStart -gt 0 ) { if( $haystack[$needleStart - 1] -eq '$' ) { $haystack = $haystack.Remove($needleStart - 1, 1) $startAt = $needleStart continue } } # Variable expressions can contain method calls, which begin and end with parenthesis, so # make sure you don't treat the close parenthesis of a method call as the close parenthesis # to the current variable expression. $needleEnd = $needleStart + 2 $depth = 0 while( $needleEnd -lt $haystack.Length ) { $currentChar = $haystack[$needleEnd] if( $currentChar -eq ')' ) { if( $depth -eq 0 ) { break } $depth-- } elseif( $currentChar -eq '(' ) { $depth++ } ++$needleEnd } $variableName = $haystack.Substring($needleStart + 2, $needleEnd - $needleStart - 2) $memberName = $null $arguments = $null # Does the variable expression contain a method call? if( $variableName -match '([^.]+)\.([^.(]+)(\(([^)]+)\))?' ) { $variableName = $Matches[1] $memberName = $Matches[2] $arguments = $Matches[4] $arguments = & { if( -not $arguments ) { return } $currentArg = New-Object 'Text.StringBuilder' $currentChar = $null $inString = $false # Parse each of the arguments in the method call. Each argument is # seperated by a comma. Ignore whitespace. Commas and whitespace that # are part of an argument must be double or single quoted. To include # a double quote inside a double-quoted string, double it. To include # a single quote inside a single-quoted string, double it. for( $idx = 0; $idx -lt $arguments.Length; ++$idx ) { $nextChar = '' if( ($idx + 1) -lt $arguments.Length ) { $nextChar = $arguments[$idx + 1] } $currentChar = $arguments[$idx] if( $currentChar -eq '"' -or $currentChar -eq "'" ) { if( $inString ) { if( $nextChar -eq $currentChar ) { [void]$currentArg.Append($currentChar) $idx++ continue } } $inString = -not $inString continue } if( $currentChar -eq ',' -and -not $inString ) { $currentArg.ToString() [void]$currentArg.Clear() continue } if( $inString -or -not [string]::IsNullOrWhiteSpace($currentChar) ) { [void]$currentArg.Append($currentChar) } } if( $currentArg.Length ) { $currentArg.ToString() } } } $envVarPath = 'env:{0}' -f $variableName if( $Context.Variables.ContainsKey($variableName) ) { $value = $Context.Variables[$variableName] } elseif( $wellKnownVariables.ContainsKey($variableName) ) { $value = $wellKnownVariables[$variableName] } elseif( (Test-Path -Path $envVarPath) ) { $value = (Get-Item -Path $envVarPath).Value } else { Write-Error -Message ('Variable ''{0}'' does not exist. We were trying to replace it in the string ''{1}''. You can: * Use the `Add-WhiskeyVariable` function to add a variable named ''{0}'', e.g. Add-WhiskeyVariable -Context $context -Name ''{0}'' -Value VALUE. * Create an environment variable named ''{0}''. * Prevent variable expansion by escaping the variable with a backtick or backslash, e.g. `$({0}) or \$({0}). * Remove the variable from the string. ' -f $variableName,$InputObject) -ErrorAction $ErrorActionPreference return $InputObject } if( $value -eq $null ) { $value = '' } if( $value -ne $null -and $memberName ) { if( -not (Get-Member -Name $memberName -InputObject $value ) ) { Write-Error -Message ('Variable ''{0}'' does not have a ''{1}'' member. Here are the available members:{2} {2}{3}{2} ' -f $variableName,$memberName,[Environment]::NewLine,($value | Get-Member | Out-String)) return $InputObject } if( $arguments ) { try { $value = $value.$memberName.Invoke($arguments) } catch { Write-Error -Message ('Failed to call ([{0}]{1}).{2}(''{3}''): {4}.' -f $value.GetType().FullName,$value,$memberName,($arguments -join ''','''),$_) return $InputObject } } else { $value = $value.$memberName } } $variableNumChars = $needleEnd - $needleStart + 1 if( $needleStart + $variableNumChars -gt $haystack.Length ) { Write-Error -Message ('Unclosed variable expression ''{0}'' in value ''{1}''. Add a '')'' to the end of this value or escape the variable expression with a double dollar sign, e.g. ''${1}''.' -f $haystack.Substring($needleStart),$haystack) return $InputObject } $haystack = $haystack.Remove($needleStart,$variableNumChars) $haystack = $haystack.Insert($needleStart,$value) # No need to keep searching where we've already looked. $startAt = $needleStart } while( $true ) return $haystack } } |