functions/message/Write-PSFMessage.ps1

function Write-PSFMessage
{
    <#
        .SYNOPSIS
            This function receives messages, then logs and reports them.
         
        .DESCRIPTION
            This function receives messages, then logs and reports them.
            Other functions hand off all their information output for processing to this function.
 
            This function will then handle:
            - Warning output
            - Error management for non-terminating errors (For errors that terminate execution or continue on with the next object use "Stop-PSFFunction")
            - Logging
            - Verbose output
            - Message output to users
 
            For the complex description on how this works and how users and developers can influence it, run:
            Get-Help about_psf_message
         
        .PARAMETER Message
            The message to write/log. The function name and timestamp will automatically be prepended.
         
        .PARAMETER Level
            This parameter represents the verbosity of the message. The lower the number, the more important it is for a human user to read the message.
            By default, the levels are distributed like this:
            - 1-3 Direct verbose output to the user (using Write-Host)
            - 4-6 Output only visible when requesting extra verbosity (using Write-Verbose)
            - 1-9 Debugging information, written using Write-Debug
 
            In addition, it is possible to select the level "Warning" which moves the message out of the configurable range:
            The user will always be shown this message, unless he silences the entire verbosity.
 
            Possible levels:
            Critical (1), Important / Output / Host (2), Significant (3), VeryVerbose (4), Verbose (5), SomewhatVerbose (6), System (7), Debug (8), InternalComment (9), Warning (666)
            Either one of the strings or its respective number will do as input.
     
        .PARAMETER Tag
            Tags to add to the message written.
            This allows filtering and grouping by category of message, targeting specific messages.
         
        .PARAMETER FunctionName
            The name of the calling function.
            Will be automatically set, but can be overridden when necessary.
     
        .PARAMETER ModuleName
            The name of the module, the calling function is part of.
            Will be automatically set, but can be overridden when necessary.
         
        .PARAMETER ErrorRecord
            If an error record should be noted with the message, add the full record here.
            Especially designed for use with Warning-mode, it can legally be used in either mode.
            The error will be added to the $Error variable and enqued in the logging/debugging system.
         
        .PARAMETER Once
            Setting this parameter will cause this function to write the message only once per session.
            The string passed here and the calling function's name are used to create a unique ID, which is then used to register the action in the configuration system.
            Thus will the lockout only be written if called once and not burden the system unduly.
            This lockout will be written as a hidden value, to see it use Get-PSFConfig -Force.
         
        .PARAMETER Target
            Add the object the message is all about, in order to simplify debugging / troubleshooting.
            For example, when calling this from a function targeting a remote computer, the computername could be specified here, allowing all messages to easily be correlated to the object processed.
         
        .PARAMETER EnableException
            This parameters disables user-friendly warnings and enables the throwing of exceptions.
            This is less user friendly, but allows catching exceptions in calling scripts.
         
        .EXAMPLE
            PS C:\> Write-PSFMessage -Level Verbose -Message "Connecting to $computer"
     
            Writes the message "Connecting to $computer" to verbose.
            Will also log the message.
     
        .EXAMPLE
            PS C:\> Write-PSFMessage -Level Warning -Message "Failed to retrieve additional network adapter information from $computer"
     
            Writes the message "Failed to retrieve additional network adapter information from $computer" as a warning.
            Will also log the message.
     
        .EXAMPLE
            PS C:\> Write-PSFMessage -Level Verbose -Message "Connecting to $computer" -Target $computer
     
            Writes the message "Connecting to $computer" to verbose.
            Includes the variable $computer in the message. This has no effect on the text shown but will be available for debugging purposes.
            Will also log the message.
     
        .EXAMPLE
            PS C:\> Write-PSFMessage -Level Host -Message "This command has been deprecated, use 'Get-NewExample' instead" -Once 'Get-Example'
     
            Writes the message "This command has been deprecated, use 'Get-NewExample' instead" to the screen.
            This message will only be shown once per powershell process.
            Will also log the message.
     
        .EXAMPLE
            PS C:\> Write-PSFMessage -Level Warning -Message "Failed to retrieve additional network adapter information from $computer" -Target $computer -ErrorRecord $_
     
            Writes the message "Failed to retrieve additional network adapter information from $computer" as a warning.
            Will also append the message of the exception to the text.
            Will also add the error record to the error log
            Will also log the message.
    #>

    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSAvoidUsingWriteHost", "")]
    [CmdletBinding()]
    Param (
        [PSFramework.Message.MessageLevel]
        $Level = [PSFramework.Message.MessageLevel]::Verbose,
        
        [Parameter(Mandatory = $true, Position = 0)]
        [string]
        $Message,
        
        [string[]]
        $Tag,
        
        [string]
        $FunctionName = ((Get-PSCallStack)[0].Command),
        
        [string]
        $ModuleName = ((Get-PSCallStack)[0].InvocationInfo.MyCommand.ModuleName),
        
        [System.Management.Automation.ErrorRecord[]]
        $ErrorRecord,
        
        [System.Exception]
        $Exception,
        
        [string]
        $Once,
        
        [switch]
        $OverrideExceptionMessage,
        
        [object]
        $Target,
        
        [bool]
        $EnableException
    )
    
    <#
    # Workflow guide #
    #----------------#
     
    Since this command has gotten a bit complex, here's a short guide to its workflow (with considerations attached)
     
    1. Process Statics
       For performance reasons, some static information is retrieved/determined at the start.
    2. Apply Transforms
       Users/Modules can specify global transforms, that can - depending on the target or exception type - transform
       those objects. For example, it could unwrap a wrapped exception or convert a live-state object into a static value object.
    3. Exception Integration
       If the user specified an exception to override anything within the error record (or compßletely without an error record),
       this integrates those into a standard error record. This has to be fairly at the top, in order for subsequent steps to have
       the finalized version and not care about this complexity.
    4. Handle Message content
       With all preliminaries dealt with, the finalized message versions are processed. Here it will create two message versions:
       - A colorful, for host output
       - A base version, stripped of all color tags, for logging
       If developer mode is enabled, it will instead create more detailed messages
    5. Handle Errors
       With all properties determined, it will now create the logging entry for errors (if any were specified).
    6. Message Modes
       Based on levels specified, it will now write to the message to the determined channels and create entries in the message log.
    #>

    
    #region Preliminary statics
    $timestamp = Get-Date
    $developerMode = [PSFramework.Message.MessageHost]::DeveloperMode
    
    $max_info = [PSFramework.Message.MessageHost]::MaximumInformation
    $max_verbose = [PSFramework.Message.MessageHost]::MaximumVerbose
    $max_debug = [PSFramework.Message.MessageHost]::MaximumDebug
    $min_info = [PSFramework.Message.MessageHost]::MinimumInformation
    $min_verbose = [PSFramework.Message.MessageHost]::MinimumVerbose
    $min_debug = [PSFramework.Message.MessageHost]::MinimumDebug
    $info_color = [PSFramework.Message.MessageHost]::InfoColor
    $dev_color = [PSFramework.Message.MessageHost]::DeveloperColor
    $silent = $false
    if ($psframework_silence) { $silent = $true }
    if ([PSFramework.Message.MessageHost]::DisableVerbosity) { $silent = $true }
    if (-not $ModuleName) { $ModuleName = "<Unknown>" }
    $fromStopFunction = (Get-PSCallStack)[1].Command -eq "Stop-PSFFunction"
    #endregion Preliminary statics
    
    #region Apply Transforms
    #region Target Transform
    if ((-not $fromStopFunction) -and ($Target -ne $null))
    {
        $Target = Convert-PsfMessageTarget -Target $Target -FunctionName $FunctionName -ModuleName $ModuleName
    }
    #endregion Target Transform
    
    #region Exception Transforms
    if (-not $fromStopFunction)
    {
        if ($Exception)
        {
            $Exception = Convert-PsfMessageException -Exception $Exception -FunctionName $FunctionName -ModuleName $ModuleName
        }
        elseif ($ErrorRecord)
        {
            $int = 0
            while ($int -lt $ErrorRecord.Length)
            {
                $tempException = Convert-PsfMessageException -Exception $ErrorRecord[$int].Exception -FunctionName $FunctionName -ModuleName $ModuleName
                if ($tempException -ne $ErrorRecord[$int].Exception)
                {
                    $ErrorRecord[$int] = New-Object System.Management.Automation.ErrorRecord($tempException, $ErrorRecord[$int].FullyQualifiedErrorId, $ErrorRecord[$int].CategoryInfo.Category, $ErrorRecord[$int].TargetObject)
                }
                
                $int++
            }
        }
    }
    #endregion Exception Transforms
    
    #region Message Level Transform
    # Never transform warning messages
    if ($Level -ne [PSFramework.Message.MessageLevel]::Warning)
    {
        $Level = Convert-PsfMessageLevel -OriginalLevel $Level -FromStopFunction $fromStopFunction -Tags $Tag -FunctionName $FunctionName -ModuleName $ModuleName
    }
    #endregion Message level Transform
    #endregion Apply Transforms
    
    #region Exception Integration
    # While conclusive error handling must happen after message handling,
    # in order to integrate the exception message into the actual message,
    # it becomes necessary to first integrate the exception and error record parameters into a uniform view
    
    # Note: Stop-PSFFunction never specifies this parameter, thus it is not necessary to check,
    # whether this function was called from Stop-PSFFunction.
    if ($Exception)
    {
        if ($ErrorRecord)
        {
            $ErrorRecord[0].Exception = $Exception
        }
        else
        {
            $ErrorRecord = @()
            $ErrorRecord += New-Object System.Management.Automation.ErrorRecord($Exception, "$($ModuleName)_$FunctionName", "NotSpecified", $Target)
        }
    }
    
    #endregion Exception Integration
    
    #region Handle Message Content
    $coloredMessage = $Message
    $baseMessage = $Message
    foreach ($match in ($baseMessage | Select-String '<c=["''](.*?)["'']>(.*?)</c>' -AllMatches).Matches)
    {
        $baseMessage = $baseMessage -replace ([regex]::Escape($match.Value)), $match.Groups[2].Value
    }
    
    if ($developerMode)
    {
        $channels_future = @()
        if ((-not $Silent) -and ($Level -eq [PSFramework.Message.MessageLevel]::Warning)) { $channels_future += "Warning" }
        if ((-not $Silent) -and ($max_info -ge $Level) -and ($min_info -le $Level)) { $channels_future += "Information" }
        if (($max_verbose -ge $Level) -and ($min_verbose -le $Level)) { $channels_future += "Verbose" }
        if (($max_debug -ge $Level) -and ($min_debug -le $Level)) { $channels_future += "Debug" }
        
        if ((Test-PSFParameterBinding "Target") -and ($null -ne $Target))
        {
            if ($Target.ToString() -ne $Target.GetType().FullName) { $targetString = " [T: $($Target.ToString())] " }
            else { $targetString = " [T: <$($Target.GetType().FullName.Split(".")[-1])>] " }
        }
        else { $targetString = "" }
        
        $newMessage = @"
[$($timestamp.ToString("HH:mm:ss"))][$FunctionName][L: $Level]$targetString[C: $channels_future][EE: $EnableException][O: $(Test-PSFParameterBinding Once)]
    $baseMessage
"@

        $newColoredMessage = @"
[<c='sub'>$($timestamp.ToString("HH:mm:ss"))</c>][<c='sub'>$FunctionName</c>][<c='sub'>L:</c> <c='em'>$Level</c>]<c='em'>$targetString</c>[<c='sub'>C:</c> <c='em'>$channels_future</c>][<c='sub'>EE:</c> <c='em'>$EnableException</c>][<c='sub'>O:</c> <c='em'>$(Test-PSFParameterBinding Once)</c>]
    $coloredMessage
"@

    }
    else
    {
        $newMessage = "[$($timestamp.ToString("HH:mm:ss"))][$FunctionName] $baseMessage"
        $newColoredMessage = "[<c='sub'>$($timestamp.ToString("HH:mm:ss"))</c>][<c='sub'>$FunctionName</c>] $coloredMessage"
    }
    
    
    if ($ErrorRecord -and (-not $OverrideExceptionMessage) -and ($Message -notmatch ([regex]::Escape("$($ErrorRecord[0].Exception.Message)"))))
    {
        $baseMessage += " | $($ErrorRecord[0].Exception.Message)"
        $newMessage += " | $($ErrorRecord[0].Exception.Message)"
        $newColoredMessage += " | $($ErrorRecord[0].Exception.Message)"
    }
    #endregion Handle Message Content

    #region Handle Errors
    if ($ErrorRecord -and (-not $fromStopFunction))
    {
        foreach ($record in $ErrorRecord)
        {
            $Exception = New-Object System.Exception($Message, $record.Exception)
            $newRecord = New-Object System.Management.Automation.ErrorRecord($Exception, "psframework_$FunctionName", $record.CategoryInfo.Category, $Target)
            
            if ($EnableException) { Write-Error -Message $newRecord -Category $record.CategoryInfo.Category -TargetObject $Target -Exception $Exception -ErrorId "psframework_$FunctionName" -ErrorAction Continue }
            else { $null = Write-Error -Message $newRecord -Category $record.CategoryInfo.Category -TargetObject $Target -Exception $Exception -ErrorId "psframework_$FunctionName" -ErrorAction Continue 2>&1 }
        }
    }
    if ($ErrorRecord)
    {
        [PSFramework.Message.LogHost]::WriteErrorEntry($ErrorRecord, $FunctionName, $ModuleName, $Tag, $timestamp, $baseMessage, ([System.Management.Automation.Runspaces.Runspace]::DefaultRunspace.InstanceId), $env:COMPUTERNAME)
    }
    #endregion Handle Errors
    
    $channels = @()
    
    #region Warning Mode
    if ($Warning -or ($Level -like "Warning"))
    {
        if (-not $Silent)
        {
            if ($PSBoundParameters.ContainsKey("Once"))
            {
                $OnceName = "MessageOnce.$FunctionName.$Once"
                
                if (-not (Get-PSFConfigValue -Name $OnceName))
                {
                    Write-Warning $newMessage
                    Set-PSFConfig -Name $OnceName -Value $True -Hidden -ErrorAction Ignore
                }
            }
            else
            {
                Write-Warning $newMessage
            }
            $channels += "Warning"
        }
        elseif ($developerMode)
        {
            Write-Host $newMessage -ForegroundColor $dev_color
        }
        
        Write-Debug $newMessage
        $channels += "Debug"
    }
    #endregion Warning Mode
    
    #region Message Mode
    else
    {
        if ((-not $Silent) -and ($max_info -ge $Level) -and ($min_info -le $Level))
        {
            if (Test-PSFParameterBinding "Once")
            {
                $OnceName = "MessageOnce.$FunctionName.$Once"
                
                if (-not (Get-PSFConfigValue -Name $OnceName))
                {
                    Write-PSFHostColor -String $newColoredMessage -DefaultColor $info_color -ErrorAction Ignore
                    Set-PSFConfig -Name $OnceName -Value $True -Hidden -ErrorAction Ignore
                }
            }
            else
            {
                Write-PSFHostColor -String $newColoredMessage -DefaultColor $info_color -ErrorAction Ignore
            }
            $channels += "Information"
        }
        elseif ($developerMode)
        {
            Write-PSFHostColor -String $newColoredMessage -DefaultColor $dev_color
        }
        
        if (($max_verbose -ge $Level) -and ($min_verbose -le $Level))
        {
            Write-Verbose $newMessage
            $channels += "Verbose"
        }
        
        if (($max_debug -ge $Level) -and ($min_debug -le $Level))
        {
            Write-Debug $newMessage
            $channels += "Debug"
        }
    }
    #endregion Message Mode
    
    $channel_Result = $channels -join ", "
    if ($channel_Result)
    {
        $entry = [PSFramework.Message.LogHost]::WriteLogEntry($baseMessage, $channel_Result, $timestamp, $FunctionName, $ModuleName, $Tag, $Level, ([System.Management.Automation.Runspaces.Runspace]::DefaultRunspace.InstanceId), $env:COMPUTERNAME, $Target)
    }
    else
    {
        $entry = [PSFramework.Message.LogHost]::WriteLogEntry($baseMessage, "None", $timestamp, $FunctionName, $ModuleName, $Tag, $Level, ([System.Management.Automation.Runspaces.Runspace]::DefaultRunspace.InstanceId), $env:COMPUTERNAME, $Target)
    }
    
    foreach ($subscription in [PSFramework.Message.MessageHost]::Events.Values)
    {
        if ($subscription.Applies($entry))
        {
            $scriptBlock = [scriptblock]::Create($subscription.ScriptBlock.ToString())
            $ExecutionContext.InvokeCommand.InvokeScript($false, $scriptBlock, $null, $entry)
        }
    }
}