functions/Test-DbaBuild.ps1

function Test-DbaBuild {
    <#
    .SYNOPSIS
        Returns SQL Server Build "compliance" level on a build
 
    .DESCRIPTION
        It answers the question "is this build up to date ?"
        Returns info about the specific build of a SQL instance, including the SP, the CU and the reference KB, End Of Support, wherever possible.
        It adds a Compliance property as true/false, and adds details about the "targeted compliance"
 
    .PARAMETER Build
        Instead of connecting to a real instance, pass a string identifying the build to get the info back.
 
    .PARAMETER MinimumBuild
        This is the build version to test "compliance" against. Anything below this is flagged as not compliant
 
    .PARAMETER MaxBehind
        Instead of using a specific MinimumBuild here you can pass "how many service packs and cu back" is the targeted compliance level
        You can use xxSP or xxCU or both, where xx is a number. See Examples for more informations
 
    .PARAMETER Latest
        Shortcut for specifying the very most up-to-date build available.
 
    .PARAMETER SqlInstance
        Target any number of instances, in order to return their compliance state.
 
    .PARAMETER SqlCredential
        When connecting to an instance, use the credentials specified.
 
    .PARAMETER Update
        Looks online for the most up to date reference, replacing the local one.
 
    .PARAMETER Quiet
        Makes the function just return $true/$false. It's useful if you use Test-DbaBuild in your own scripts, like
            if (Test-DbaBuild -Build "12.0.5540" -MaxBehind "0CU" -Quiet) {
                Do-Something
            }
 
    .PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.5540" -MinimumBuild "12.0.5557"
 
        Returns information about a build identified by "12.0.5540" (which is SQL 2014 with SP2 and CU4), which is not compliant as the minimum required
        build is "12.0.5557" (which is SQL 2014 with SP2 and CU8)
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.5540" -MaxBehind "1SP"
 
        Returns information about a build identified by "12.0.5540", making sure it is AT MOST 1 Service Pack "behind". For that version,
        that identifies an SP2, means accepting as the lowest compliance version as "12.0.4110", that identifies 2014 with SP1
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.5540" -MaxBehind "1SP 1CU"
 
        Returns information about a build identified by "12.0.5540", making sure it is AT MOST 1 Service Pack "behind", plus 1 CU "behind". For that version,
        that identifies an SP2 and CU, rolling back 1 SP brings you to "12.0.4110", but given the latest CU for SP1 is CU13, the target "compliant" build
        will be "12.0.4511", which is 2014 with SP1 and CU12
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.5540" -MaxBehind "0CU"
 
        Returns information about a build identified by "12.0.5540", making sure it is the latest CU release.
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.5540" -Latest
 
        Same as previous, returns information about a build identified by "12.0.5540", making sure it is the latest build available.
 
    .EXAMPLE
        Test-DbaBuild -Build "12.00.4502" -MinimumBuild "12.0.4511" -Update
 
        Same as before, but tries to fetch the most up to date index online. When the online version is newer, the local one gets overwritten
 
    .EXAMPLE
        Test-DbaBuild -Build "12.0.4502","10.50.4260" -MinimumBuild "12.0.4511"
 
        Returns information builds identified by these versions strings
 
    .EXAMPLE
        Get-DbaRegisteredServer -SqlInstance sqlserver2014a | Test-DbaBuild -MinimumBuild "12.0.4511"
 
        Integrate with other commandlets to have builds checked for all your registered servers on sqlserver2014a
 
    .NOTES
        Author: niphlod
        Editor: Fred
        Tags: SqlBuild
 
        dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
        Copyright (C) 2016 Chrissy LeMaire
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Test-DbaBuild
#>

    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSUseShouldProcessForStateChangingFunctions", "")]
    [CmdletBinding()]
    param (
        [version[]]
        $Build,

        [version]
        $MinimumBuild,

        [string]
        $MaxBehind,

        [switch]
        $Latest,

        [parameter(Mandatory = $false, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]
        $SqlInstance,

        [Alias("Credential")]
        [PSCredential]
        $SqlCredential,

        [switch]
        $Update,

        [switch]
        $Quiet,

        [switch]
        [Alias('Silent')]$EnableException
    )

    begin {
        #region Helper functions
        function Get-DbaBuildReferenceIndex {
            [CmdletBinding()]

            $DbatoolsData = Get-DbatoolsConfigValue -Name 'Path.DbatoolsData'
            $writable_idxfile = Join-Path $DbatoolsData "dbatools-buildref-index.json"
            $result = Get-Content $writable_idxfile -Raw | ConvertFrom-Json
            $result.Data | Select-Object @{ Name = "VersionObject"; Expression = { [version]$_.Version } }, *
        }

        $ComplianceSpec = @()
        $ComplianceSpecExclusiveParams = @('MinimumBuild', 'MaxBehind', 'Latest')
        foreach ($exclParam in $ComplianceSpecExclusiveParams) {
            if (Test-Bound -Parameter $exclParam) { $ComplianceSpec += $exclParam }
        }
        if ($ComplianceSpec.Length -gt 1) {
            Stop-Function -Category InvalidArgument -Message "-MinimumBuild, -MaxBehind and -Latest are mutually exclusive. Please choose only one. Quitting."
            return
        }
        if ($ComplianceSpec.Length -eq 0) {
            Stop-Function -Category InvalidArgument -Message "You need to choose one from -MinimumBuild, -MaxBehind and -Latest. Quitting."
            return
        }
        try {
            # Empty call just to make sure the buildref is updated and on the right path
            Get-DbaBuildReference -Update:$Update -EnableException:$true
            $IdxRef = Get-DbaBuildReferenceIndex
        }
        catch {
            Stop-Function -Message "Error loading SQL build reference" -ErrorRecord $_
            return
        }
        if ($MaxBehind) {
            $MaxBehindValidator = [regex]'^(?<howmany>[\d]+)(?<what>SP|CU)$'
            $pieces = $MaxBehind.Split(' ')    | Where-Object { $_ }
            try {
                $ParsedMaxBehind = @{}
                foreach ($piece in $pieces) {
                    $pieceMatch = $MaxBehindValidator.Match($piece)
                    if ($pieceMatch.Success -ne $true) {
                        Stop-Function -Message "MaxBehind has an invalid syntax ('$piece' could not be parsed correctly)" -ErrorRecord $_
                        return
                    }
                    else {
                        $howmany = [int]$pieceMatch.Groups['howmany'].Value
                        $what = $pieceMatch.Groups['what'].Value
                        if ($ParsedMaxBehind.ContainsKey($what)) {
                            Stop-Function -Message "The specifier $what has been already passed" -ErrorRecord $_
                            return
                        }
                        else {
                            $ParsedMaxBehind[$what] = $howmany
                        }
                    }
                }
                if (-not $ParsedMaxBehind.ContainsKey('SP')) {
                    $ParsedMaxBehind['SP'] = 0
                }
            }
            catch {
                Stop-Function -Message "Error parsing MaxBehind" -ErrorRecord $_
                return
            }
        }
    }
    process {
        if (Test-FunctionInterrupt) { return }
        $hiddenProps = @()
        if (-not $SqlInstance) {
            $hiddenProps += 'SqlInstance'
        }
        if ($MinimumBuild) {
            $hiddenProps += 'MaxBehind', 'SPTarget', 'CUTarget', 'BuildTarget'
        }
        elseif ($MaxBehind -or $Latest) {
            $hiddenProps += 'MinimumBuild'
        }
        $BuildVersions = Get-DbaBuildReference -Build $Build -SqlInstance $SqlInstance -SqlCredential $SqlCredential -Update:$Update -EnableException:$EnableException
        foreach ($BuildVersion in $BuildVersions) {
            $inputbuild = $BuildVersion.Build
            $compliant = $false
            $targetSPName = $null
            $targetCUName = $null
            if ($BuildVersion.MatchType -eq 'Approximate') {
                Stop-Function -Message "$($BuildVersion.Build) is not recognized as a correct version" -ErrorRecord $_ -Continue
            }
            if ($MinimumBuild) {
                Write-Message -Level Debug -Message "Comparing $MinimumBuild to $inputbuild"
                if ($inputbuild -ge $MinimumBuild) {
                    $compliant = $true
                }
            }
            elseif ($MaxBehind -or $Latest) {
                $IdxVersion = $IdxRef | Where-Object Version -like "$($inputbuild.Major).$($inputbuild.Minor).*"
                $lastsp = ''
                $SPsAndCUs = @()
                foreach ($el in $IdxVersion) {
                    if ($null -ne $el.SP) {
                        $lastsp = $el.SP | Where-Object { $_ -ne 'LATEST' }
                        $SPsAndCUs += @{
                            VersionObject = $el.VersionObject
                            SP            = $lastsp
                        }
                    }
                    if ($null -ne $el.CU) {
                        $SPsAndCUs += @{
                            VersionObject = $el.VersionObject
                            SP            = $lastsp
                            CU            = $el.CU
                        }
                    }
                }
                $targetedBuild = $SPsAndCUs[0]
                if ($Latest) {
                    $targetedBuild = $IdxVersion[$IdxVersion.Length - 1]
                }
                else {
                    if ($ParsedMaxBehind.ContainsKey('SP')) {
                        $AllSPs = $SPsAndCUs.SP | Select-Object -Unique
                        $targetSP = $AllSPs.Length - $ParsedMaxBehind['SP'] - 1
                        if ($targetSP -lt 0) {
                            $targetSP = 0
                        }
                        $targetSPName = $AllSPs[$targetSP]
                        Write-Message -Level Debug -Message "Target SP is $targetSPName - $targetSP on $($AllSPs.Length)"
                        $targetedBuild = $SPsAndCUs | Where-Object SP -eq $targetSPName | Select-Object -First 1
                    }
                    if ($ParsedMaxBehind.ContainsKey('CU')) {
                        $AllCUs = ($SPsAndCUs | Where-Object VersionObject -gt $targetedBuild.VersionObject).CU | Select-Object -Unique
                        if ($AllCUs.Length -gt 0) {
                            #CU after the targeted build available
                            $targetCU = $AllCUs.Length - $ParsedMaxBehind['CU'] - 1
                            if ($targetCU -lt 0) {
                                $targetCU = 0
                            }
                            $targetCUName = $AllCUs[$targetCU]
                            Write-Message -Level Debug -Message "Target CU is $targetCUName - $targetCU on $($AllCUs.Length)"
                            $targetedBuild = $SPsAndCUs | Where-Object VersionObject -gt $targetedBuild.VersionObject | Where-Object CU -eq $targetCUName | Select-Object -First 1
                        }
                    }
                }
                if ($inputbuild -ge $targetedBuild.VersionObject) {
                    $compliant = $true
                }
            }
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name Compliant -Value $compliant
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name MinimumBuild -Value $MinimumBuild
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name MaxBehind -Value $MaxBehind
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name SPTarget -Value $targetSPName
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name CUTarget -Value $targetCUName
            Add-Member -InputObject $BuildVersion -MemberType NoteProperty -Name BuildTarget -Value $targetedBuild.VersionObject
            if ($Quiet) {
                $BuildVersion.Compliant
            }
            else {
                $BuildVersion | Select-Object * | Select-DefaultView -ExcludeProperty $hiddenProps
            }
        }
    }
    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -EnableException:$false -Alias Test-DbaSqlBuild
    }
}