Powershell Script Capture Cmdlet Result/Errors - powershell

I'm writing a small Powershell script (.ps1 file) to allow some of our users to manage active directory users in a very simple interface. The problem is, I'm having trouble capturing the result/output from a cmdlet like New-ADUser to see if it was successful.
I'm looking for a way to obtain the result of a cmdlet like New-ADUser so that I can gracefully tell the user whether or not the user was created successfully.
Just for further info, this is just a small app running a System.Windows.Forms.Form and it starts with the command line window hidden.
In the past for some of our tech guys, I've run the little powershell app with the command line open in the background. That way they see the red error message fly by and can debug, but that won't work for these everyday users.

What have you tried?
It's not different from your normal error handling. Set your $ErrorActionPreference to e.g. Stop, and use try/catch to run commands and catch the errors.
$ErrorActionPreference = "Stop"
try {
#Run code
} catch {
#Handle error objects, which you access with $_
}

Related

Question about ISE vs Console with SystemEvents

When I run the following in PowerShell ISE, it works perfectly, gives me the reason "AccountLock" or "AccountUnlock" exactly as it's supposed to. However, when I run this exact command in an elevated powershell console, it does not return the sessionswitch reason at all in console. It returns nothing after an unlock.
I checked Get-EventSubscriber as well as Get-Job and both look successfully created.
Screenshot of Subscriber & Job:
Register-ObjectEvent -InputObject $([microsoft.win32.systemevents]) -EventName "SessionSwitch" -Action {write-host $event.SourceEventArgs.Reason}
One thing I would like to do is have windows detect when the session is unlocked (after a user syncs their password with the domain) and open a program.
OS: Windows 10
Version: 5.1 Build 17134 R 590
After a lot of looking around, i couldn't find a good way to use [windows.win32.systemevents], so i reached out to Lee Holmes. He said it is because the powershell console host runs by default in the Single Thread Apartment (STA) model. If you run it in MTA, it works fine.
Simplest workaround is to use code similar to this at the beginning of your script to ensure you are in MTA mode, and if start a new powershell process if you are not and reload the script.
if ([System.Threading.Thread]::CurrentThread.ApartmentState -ne [System.Threading.ApartmentState]::MTA)
{
powershell.exe -MTA -File $MyInvocation.MyCommand.Path
return
}
Have a look to Microsoft documentation : SystemEvents.SessionSwitch Event, the explanation seems to be that this message is sent to message pump which is the part of code that process graphic messages. You perhaps can try to use an hidden form in your code to force creation of a message pump.
Note :
This event is only raised if the message pump is running. In a Windows service, unless a hidden form is used or the message pump has been started manually, this event will not be raised. For a code example that shows how to handle system events by using a hidden form in a Windows service, see the SystemEvents class.

Powershell - Log file

I have a PowerShell script, at its begining I added: $ErrorActionPreference = "Stop". It's good, if there is an error the script won't go further.
Fact is that when an error occurs, the script stop and exit itself and so, I can not see the error.
The best option is to crate a logfile that will write EVERYTHING that was in the PowerShell terminal, including succesful lines.
If not, at least make the terminal keep opened even if an error occurs, but stop the script.
I would recommend Start-Transcript:
The Start-Transcript cmdlet creates a record of all or part of a
PowerShell session to a text file. The transcript includes all command
that the user types and all output that appears on the console.

Powershell to EXE tool Advice

So here's the deal. Because of a number of... let's just say not PowerShell smart people who will be using an incredibly complex application that I just finished, I need the ability to package it in an exe wrapper.
This shouldn't be that hard
I was able to successfully use PS2EXE, except for some reason with AD, it throws out a whooooole bunch of AD text that I can't get rid of. Tried to fix that for a few days before getting frustrated and moving on.
Then, I discovered PowerGUI. I can't say that I like it, at all. However, its compiler was exactly what I was looking for! Except for the fact that Exchange 2010 snap-ins are not compatible with .NET 4.5 through this application.
I want to make it very clear that my script works perfectly on multiple different computers, but as soon as I use any of these tools, everything breaks.
An exe is the best thing that I can think of to simplify the interface, and keep the Technically Intellectually Stunted from breaking everything, or running to me with every little error because they somehow got into the code and typed something and saved it, and now nothing works and it's the end of the world and they have no idea what happened.
If you guys know of any tools to wrap this up into an exe, or have any other ideas on how to help, I would really appreciate anything you guys can give me.
You have never failed me in the past!
From my point of view if you really want an EXE file you should write a .NET application, it's not so hard to embed PowerShell CmdLets.
In order to avoid end user modifying your code I know two solutions :
First : set execution policy to AllSigned on the user computer and sign the scripts you deploy. You can manage to use our own certificates (not expensive at all) or public certificates (more expensive). One of the drawback of this solution is that it does not prevent users from seeing the code. Another big drawback is that a PKI and sign code infrastructure is a lot of wast time.
Second : for non interactive scripts (be carefull it's a kind of makeshift job) :
Create a new user account
Only allow access to the script file for the new account.
Set up a task in the Windows scheduler to run that script file with PowerShell under that specific account. The permissions for the scheduled tasks allow read and execute access to the user(s). Then set the task to "disabled".
Whenever the script file needs to be run, the corresponding task is manually started by the user.
Using this solution will also allow you to remote execute your script.
When I had a similar deployment problem - 1) user's didn't know powershell 2) I didn't want them to have to understand things like execution policy, 3) how to start PS, 4) etc. I wrapped it in a batch file. I also wanted to make sure that experienced PS users still had the capabilities of PS, so the batch file determined if it was running under PS or not and ran in the current PS session if applicable. I was never too worried that users would mess with the script - they were happy if it "just worked". So whether users liked Explorer, CMD.EXE, or PS, they all were accommodated.
The batch file I wrote first runs a bit of powershell code to determine if the process of the batch file is the grandchild of a powershell process. If it is then the batch file is being invoked from PS. The execution policy is also checked and if it is lenient enough then Wscript.SendKeys is used to send keystrokes to PS to get the script running in the current PS session. If it isn't then it starts a new PS session using -ExecutionPolicy parameter and passes the script as a command line argument (-Command).
This bit of powershell code communicates back to the .CMD file using a return code. Sorry it's cryptic, but the length of command line parameters is limited. Here's the code:
set scr= $mp=[diagnostics.process]::getcurrentprocess().id
set scr=%scr%; $pp=([wmi]\"win32_process.handle='$mp'\").parentprocessid
set scr=%scr%; $gp=([wmi]\"win32_process.handle='$pp'\").parentprocessid
set scr=%scr%; $ep=[int][microsoft.powershell.executionpolicy](get-executionpolicy)
set scr=%scr%; try {$pnp=1-[int](([wmi]\"win32_process.handle='$gp'\").Name -eq \"powershell.exe\")
set scr=%scr%; } catch {$pnp=1}
set scr=%scr%; $ev = (8 * $pnp + $ep) -band 0xB; %wo% pp: $pp gp: $gp ev: $ev; if ($ev -le 1) {
set scr=%scr% %wo% Launching within existing powershell session...`n;
set scr=%scr% $w=new-object -com wscript.shell;$null=$w.appactivate($gp);
set scr=%scr%; $w.sendkeys(\"^&{{}`$st =cat "%me%";`$sc=`$st -join [char]10 -split 'rem PS script';
set scr=%scr% `$script:myArgs = `\" %*`\";`$sb=[scriptblock]::create{(} `$sc[3]{)};. `$sb{}}~\")
set scr=%scr%; }
set scr=%scr%; exit $ev
powershell -noprofile -Command %scr%
%wo% is to allow debugging this "checker script". If debugging is on the %wo% is set to write-host. Otherwise it is set to define a "null" function and then invoke the null function. The null doesn't do anything so the message that is the argument to the function is not output.
Note the escaping when invoking SendKeys. ^ is the CMD.EXE escape character and SendKeys has it's own escape mechanism, as does PS.
If run from PS you end up in a PS session thanks to SendKeys. Otherwise the batch file does this:
set scr= ren function:prompt prompto
set scr=%scr%; function prompt{ 'myApp: '+(prompto)}
set scr=%scr%; $st= (cat %me%) -join \"`n\";
set scr=%scr%; $sx=($st -split 'rem PS script')
set scr=%scr%; $sc=$sx[3]
set scr=%scr%; %wo% myArgs: $myArgs script length: $sc.length
set scr=%scr%; ^&{$script:myArgs=\"%*\"; iex $sc}
title MyApp
rem Change the number of lines on the console if currently set to 25
for /f "tokens=2" %%i in ('mode con^|findstr Lines:') do if %%i LEQ 25 (mode con lines=50&color 5F)
powershell -noexit -noprofile -command "%scr%"
This "helper script" also can't be too long. So the helper script reads the original .CMD file and then splits it by using the string 'rem PS script'. That string will be in both this helper script as well as in the batch file (separating the batch file statements from PS statements). In my case the string is also in the batch file comments, so that is why the index of 3 is used.
Your PS script can define functions or a module. Your PS script can also output some introductory info to explain to users how to get started, how to get help, or whatever you want.
Rather than just using the PS command line, your PS script could create it's own interactive environment (using Read-Host for example). However I didn't want to do that because it would have prevented experienced PS users from using their knowledge about PS. For example if your script requires a username/password, an experienced PS user could use get-credential to create a credential to send to your script.

Powershell config to force a batch file to run within the powershell window?

I've got a powershell script that eventually passes a stack of arguments into a batch file via invoke-expression command.
However, on one server, when the powershell scripts executes that batch file, that batch file opens in a new window, but on the other server, the batch file executes within the powershell window.
What that means, is that I've got a sleep interval that is starting once the batch file begins executing in the new window, and thus screwing up my timings, unlike the other server, where the sleep interval doesn't begin until after the batch file has finished executing.
So my question is... does anybody know why the behaviours are different between the two servers, and how to get the batch file to execute in the powershell window? I'm thinking it's a configuration thing, but can't actually find anything that tells me how to make it do what I want it to do.....
Thanks!
--edit--
I'm currently just piping the line straight through like this:
E:\Software\ibm\WebSphere\AppServer\bin\wsadmin -lang jython -username $($username) -password $($password) -f "F:\Custom\dumpAllThreads.py" $($servers)
Previously, it was
$invokeString = 'E:\Software\ibm\WebSphere\AppServer\bin\wsadmin -lang jython -username $($username) -password $($password) -f "F:\Custom\dumpAllThreads.py" $($servers)'
$output = invoke-expression $invokeString
Both had the same behaviour.
So my question is... does anybody know why the behaviours are different between the two servers
Most often I've seen this sort of thing related to how a scripts is called. If the same user is logged on multiple times on the same server (i.e., console and RDP) then the window might appear in a different session. Similarly, if the script runs as a scheduled task and the user that runs the task isn't the user logged on, the window will never be visible. If the same user is logged on, it might be visible.
how to get the batch file to execute in the powershell window?
You could try Start-Process with -NoNewWindow, as #Paul mentions.
However....
What that means, is that I've got a sleep interval that is starting once the batch file begins executing in the new window, and thus screwing up my timings, unlike the other server, where the sleep interval doesn't begin until after the batch file has finished executing.
It sounds like your actual problem is that your code has a race condition. You should fix the actual problem. Use Start-Process with the -Wait parameter, or use the jobs system in PowerShell.

Powershell window disappears before I can read the error message

When I call a Powershell script, how can I keep the called script from closing its command window. I'm getting an error and I'm sure I can fix it if I could just read the error.
I have a Powershell script that sends an email with attachment using the .NET classes. If I call the script directly by executing it from the command line or calling it from the Windows Scheduler then it works fine. If I call it from within another script (IronPython, if that matters) then it fails. All scenarios work fine on my development machine. (I really do have to get that "Works on My Machine" logo!) I've got the call to Powershell happening in a way that displays a command window and I can see a flicker of red just before it closes.
Sorry: Powershell 1.0, IronPython 1.1
Solution: powershell -noexit d:\script\foo.ps1
The -noexit switch worked fine. I just added it to the arguments I pass from IronPython. As I suspected, it's something that I can probably fix myself (execution policy, although I did temporarily set as unrestricted with no effect, so I guess I need to look deeper). I'll ask another question if I run into trouble with that.
Thanks to all for the help. I learned that I need to investigate powershell switches a little more closely, and I can see quite a few things that will prove useful in the future.
Try with the -noexit switch:
powershell -noexit d:\script\foo.ps1
You basically have 3 options to prevent the PowerShell Console window from closing, that I describe in more detail on my blog post.
One-time Fix: Run your script from the PowerShell Console, or launch the PowerShell process using the -NoExit switch. e.g. PowerShell -NoExit "C:\SomeFolder\SomeScript.ps1"
Per-script Fix: Add a prompt for input to the end of your script file. e.g. Read-Host -Prompt "Press Enter to exit"
Global Fix: Change your registry key to always leave the PowerShell Console window open after the script finishes running.
Here are the registry keys to modify for option #3:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\Applications\powershell.exe\shell\open\command]
#="\"C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe\" -NoExit \"& \\\"%1\\\"\""
[HKEY_CLASSES_ROOT\Microsoft.PowerShellScript.1\Shell\0\Command]
#="\"C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe\" -NoExit \"-Command\" \"if((Get-ExecutionPolicy ) -ne 'AllSigned') { Set-ExecutionPolicy -Scope Process Bypass }; & \\\"%1\\\"\""
See my blog for more information and a .reg file that will apply these registry changes automatically.
I've needed this before and usually I didn't want to modify the script (typically for scripts fired off from the Task Scheduler). I just wanted to see what was spit out to console.
All you need to do is just append a Read-Host command after the script invocation e.g.:
PowerShell.exe -command { .\foo.ps1; read-host "Press enter key to continue" }
BTW the problem with using Start-Transcript is that it doesn't capture EXE output. And any form of attempted logging in V1 and even V2 with the standard host will not capture the verbose, debug, progress or warning streams. You can only see these by viewing the associated host window.
One cheesy but effective way to capture all script output (stdout, stderr, verbose, warning, debug) is to use another host like cmd.exe e.g.:
cmd.exe /c powershell.exe "$pwd\foo.ps1" > foo.log
I am generaly fine with scripts autoclosing except when an error occurs, where I need to see the error. Assuming you have not changed $ErrorActionPreference away from the default 'Continue', then for the behaviour I described do this at the end of you script
if ($Error)
{
Pause
}
There is no ordinary Try...Catch construction in Powershell; however you can trap exceptions instead and react properly.
I.E:
Function Example() {
trap [Exception] {
write-host "We have an error!";
write-error $("ERROR: " + $_.Exception.Message);
sleep 30;
break;
}
write-host "Hello world!";
throw "Something very bad has happened!";
}
You can also simulate Try...Catch construction:
Function Example2() {
${
write-host "Our try clause...";
throw "...caused an exception! It hurts!";
}
trap [Exception] {
write-error $_.Exception.Message;
sleep 30;
continue;
}
Of course as soon as you will trap an exception, you can log it, sleep, or whatever you want with the error message. My examples just sleep, allowing you to read what happened, but it's much better to log all the errors. (The simplest way is to redirect them with >>).
Look also at:
http://huddledmasses.org/trap-exception-in-powershell/
A quick and dirty solution is to use CTRL+S to halt the scrolling of the display and CTRL+Q to resume it.
You have three options:
Do a catch in the script (if using
Powershell V2)
Write a dummy
script which catches and redirects
stdout which you can then access as a
variable from your IronPython script.
VBS/Wscript Intro An addition to
this is just liberally drop
Read-Host commands everywhere,
and hit return to page through.
Rather than outputting anything to the shell, wrap your powershell script in a second script that redirects all output to a log file.
PS C:> myscript.ps1 |Out-File myscript.log
Create run_ps_script.bat file containing
#PowerShell.exe -command "try { %1 } finally { read-host 'Press ENTER...' }"
and make it default program to open PowerShell scrips.
My solution was to execute the script with a command line from the console window instead of right-clicking the file -> execute with powershell.
The console keeps displaying the error messages,
even though the execution of the script ended.
Have you thought about redirecting stdout and stderr to a file ex:
./ascript.ps1 >logs 2>&1
Note: You can create wrapper script in powershell that calls your powershell script with all necessary redirections.
My .PS1 script ran fine from the Powershell console but when "double-clicking" or "right-click open with powershell" it would exhibit the 'open/close' problem.
The Fix for me was to rename the script folder to a Name Without Spaces.
Then it all worked - Windows couldn't deal with
"C:\This is my folder\myscript.ps1" but
"C:\This_is_my_folder\myscript.ps1" worked just fine
A couple more ideas...You could use the start-sleep cmdlet at the end of you script to give you enough time to review the error.
You might also be able to use start-transcript to record the session to a text file.