PowerShell Log Function Readability - powershell

Question

Currently my log function spits out the information in a single column and is hard to read. Is there a way to make it split up into different columns which each (DisplayName, PoolName, PoolSnapshot, and DesktopSVIVmSnapshot) and its respective information is put correctly?
function log ([string]$entry) {
Write-Output $entry | Out-File -Append "C:\logs\SNAPSHOT.csv"
}
Add-PSSnapin Quest.ActiveRoles.ADManagement
$date = Get-Date -Format "MM-dd-yyyy"
$time = Get-Date -Format "hh:mm:sstt"
# begin log
log $(Get-Date)
log "The below Desktops are not using the correct Snapshot."
if (#($DesktopExceptions).Count -lt 1) {
Write-Output "All desktops in $pool are currently using the correct snapshots." |
Out-File -Append "C:\logs\SNAPSHOT.csv"
} else {
Write-Output $DesktopExceptions |
Select-Object DisplayName,PoolName,PoolSnapshot,DesktopSVIVmSnapshot |
sort DisplayName |
Out-File -Append "C:\logs\SNAPSHOT.csv"
}
log $(Get-Date)
09/11/2017 12:16:17
DisplayName PoolName PoolSnapshot DesktopSVIVmSnapshot
----------- -------- ------------ --------------------
xxxc-13v xxxc-xxx /8-11-2017/09-07-2017 /8-11-2017
xxxc-15v xxxc-xxx /8-11-2017/09-07-2017 /8-11-2017
xxxc-1v xxxc-xxx /8-11-2017/09-07-2017 /8-11-2017
xxxc-20v xxxc-xxx /8-11-2017/09-07-2017 /8-11-2017
Note: I removed parts of the log for in the hopes to not make the post long.

Answer 1

CSV files require uniform lines: a header line with column names, followed by data lines containing column values.
By writing the output from Get-Date first - a single date/time string - followed by another single-string output, followed by multi-column output from your $DesktopExceptions | Select-Object ... call, you're by definition not creating a valid CSV file.
If you still want to create such a file:
log (Get-Date) # With a single command, you don't need $(...) - (...) will do.
log "The below Desktops are not using the correct Snapshot."
If ($DesktopExceptions) # a non-empty array / non-$null object
{
log ($DesktopExceptions |
Select-Object DisplayName,PoolName,PoolSnapshot,DesktopSVIVmSnapshot |
Sort-Object DisplayName |
ConvertTo-Csv -NoTypeInformation)
}
Else
{
log "All desktops in $pool are currently using the correct snapshots."
}
log (Get-Date)
By defining your log() function's parameter as type [string], you're effectively forcing stringification of whatever object you pass to it. This stringification is the same you get when you embed a variable reference or command inside "..." (string expansion / interpolation) - but it is not the same as what you get by default, when you print to the console.
Out-File, by contrast, does result in the same output you get when printing to the console, which, however, is a format for human consumption, not for machine parsing (as CSV is, for instance).
To get CSV-formatted output, you must either use Export-Csv - to write directly to a file - or ConvertTo-Csv- to get a string representation.
Also note that there's typically no reason to use Write-Output explicitly - any command / expression's output that is not explicitly assigned to a variable / redirected (to a file or $null) is implicitly sent to PowerShell's [success] output stream; e.g., Write-Output Get-Date is the same as just Get-Date.

Answer 2

It looks like you're just writing an object, and taking the default PowerShell formatter behavior.
A better thing to do is make your log only responsible for one thing - writing messages to a file (no formatting). Here's an example of what you might try:
function Write-LogMessage {
[CmdletBinding()]
param (
[Parameter(Mandatory = $true, HelpMessage = "The text-content to write to the log file.",
ValueFromPipeline = $true)]
[string]$Text
)
Process {
Write-Host -ForegroundColor Green $Text
}
}
Set-Alias log Write-LogMessage
Note: This example writes directly to the PowerShell console, but you would in practice need to direct output to a file (using Out-File or one of the redirection operators - see Get-Help about_Operators).
To use it, you would write something like this:
"This is a message that would be written" | Write-LogMessage
For your specific example, you could just format the message inline, and pipe it:
Write-Output $DesktopExceptions | Select-Object DisplayName,PoolName,PoolSnapshot,DesktopSVIVmSnapshot | sort DisplayName | ForEach-Object { "{0}: Host = {1}, Pool = {2}, Pool SN = {3}, SVIV Snapshot = {4}" -f (Get-Date), $_.DisplayName, $_.PoolName, $_.PoolSnapshot, $_.DesktopSVIVmSnapshot } | log
Note that you don't need the log statement: just add formatting before piping to the Out-File cmdlet, and you'll get what you're after.
Edit: The OP asked in the original post how to format columns (tabular output). To achieve this, you can use either the ConvertTo-Csv or Export-Csv cmdlets (generally, you would use the -NoTypeInformation switch parameter with these commands, to avoid the first line of the output being a type definition). An example of this is:
$DesktopExceptions | Select-Object DisplayName,PoolName,PoolSnapshot,DesktopSVIVmSnapshot | sort DisplayName | Export-Csv C:\Temp\Datum.csv -NoTypeInformation
As pointed out in another answer, using Write-Output is not required, because PowerShell automatically writes all output to the output stream unless otherwise directed (using file redirection, a redirection operator, or the Out-Null cmdlet).

Answer 3

Please read my answer as part solution and part advice.
The "problem" with PowerShell is that it doesn't capture only the output of your code. It will capture output from other scripts, modules and executables. In other words, any attempt to make logging behave like it's generated by e.g. C# with NLOG, has an inherent problem.
I looked into this subject myself for a complex continuous delivery pipeline I'm building. I understood that a structured log will not be 100% possible and therefore I accepted the purpose of PowerShell transcription (Start-Transcript). But still I wanted to avoid creating functions like Write-Log and if possible provide an enhanced output for all code that uses Write-Debug, Write-Verbose functionality.
I ended up creating XWrite PowerShell module which works very well, even to my own suprize. I use it because it enhances the produced trace message by the caller's name (cmdlet or script) and a timestamp. The caller's name helps a lot with troubleshooting and the timestamp I use to implicitly benchmark. here are a couple of example
DEBUG: Test-MyXWrite.ps1: Hello
DEBUG: Script: Test-MyXWrite.ps1: 20170804: 10:57:27.845: Hello
There are some limitations though. Any binary's code trace output will not be enhanced. Also if a cmllet refers explicitly to the Write-* using their full namespace it will not work. To capture line by line all trace and output requires some very deep into the .net types of PowerShell implementation hooking. There is a guy who has done this, but I don't want to get influence the PowerShell process's behavior that aggresively. And at this moment I believe that to be the role of the transcription.
If you like the idea, install the module from XWrite
At some point, I would like to extend the module with a redirection to telemetry services, but I've still not decided I want to do that, because I will not capture the above mentioned exceptions and other executable. It will just offer me visible progress as the script is executing.