Powershell exitcode from MDM - powershell

I'm writing a powershell script that:
Downloads a file
Checks it's hashsum
If hashsum is correct it installs it
If hashsum is incorrect it does not install it
I have a problem, where I'm using an MDM to deploy it automatically on many machines at the same time. Feedback from MDM shows that installation failed - but installed file works as intended for sure. Therefore most likely MDM receives bad return value. MDM exits code are like this
Success exit code equal 0
Failed exit code not equal 0
So: How to make sure powershell script return Success after 3. If hashsum is correct it installs it
Will $LASTEXITCODE = 0 make it work?

Just use exit and the exit code you want. Like:
Function CustomExit{
Write-Output "This function returns exit code 1613"
Exit 1613 # Custom Exit Code
}
CustomExit
to test just run the file and give out the exitcode
PS C:\script> .\CustomExitCode.ps1
This function returns exit code 1613
PS C:\script> $LASTEXITCODE
1613
PS C:\script>

Related

How to return non zero exit code from a Powershell module function without closing the powershell console?

My powershell module has a function and I want it to return a non zero exit code. However, being a module function it is loaded into the context of the powershell console when I run Import-Module. So, when the function executes exit 1 - poof, goes the console window!
At least, this is how I explain it closing the powershell window when it exits.
So, how can a ps module function exit with a non zero exit code without killing the console where the module was imported?
P.S.
I did notice several questions on SO about this subject, but none seems to examine this particular case.
EDIT 1
I would like to provide some context. I have a PS module with a lot of functions. Some of them are used as is in Azure DevOps yaml build scripts. The latter knows to recognize non zero exit code and abort the pipeline, so it is not necessary to throw from a function to abort the flow.
However, if I want to call that function from the console, e.g. to test something quickly and it exits with non zero code, the whole console window is closed. This is extremely annoying.
Sometimes there is a workaround. So, instead of this code:
dotnet build ...
$ExitCode = $LastExitCode
DoSomethingInAnyCase()
if ($ExitCode)
{
exit $ExitCode
}
We can have the following version:
try
{
dotnet build ...
}
finally
{
DoSomethingInAnyCase()
}
Both versions would correctly return the right exit code, but because the second one does not have the explicit exit statement, it does not close the console.
You'll have to set $global:LASTEXITCODE in order to set the exit code, but note that PowerShell functions aren't really meant to set exit codes, only scripts, and the latter only for reporting exit codes to the outside world, via the PowerShell process' own exit code, when PowerShell is called via its (CLI powershell.exe for Windows PowerShell, pwsh for PowerShell Core) from a build tool, scheduled task, or another shell, for instance.
Also note that setting $global:LASTEXITCODE directly:
does not make $?, the automatic success-status variable, reflect $false in the caller's context, the way that exit <nonzero-value> does from a script and the way that calling an external program that reports a nonzero exit code does.
is not enough to make the PowerShell process as a whole report this exit code.
In short: All this gains you is that the caller can inspect $LASTEXITCODE after your function was called, as you would after calling an external program.
Generally, exit codes are an inter-process concept and do not fit well into PowerShell's in-process world.
For more information about exit codes in PowerShell, see this post.
PowerShell's analog to exit codes is $?, the automatic, Boolean success-status variable ($true or $false), which reflects a PowerShell command's success immediately afterwards.
(If that command is an external-program call, an exit code of 0 sets $? to $true, and any nonzero one sets it to $false).
As it turns out, setting that was what you really meant to ask.
As of PowerShell Core 7.0.0-preview.5, you cannot set $? directly.
For now, these are the only ways to cause $? to reflect $false in the caller's scope, and, conversely, you cannot always ensure that it is $true:
From a script: Exit the script with exit <nonzero-integer>
From a cmdlet or function (script as well):
Throw a script-terminating error (Throw) or a statement-terminating error ($PSCmdlet.ThrowTerminatingError()) - the latter being only available in advanced functions and scripts.
Write an error to PowerShell's error stream with $PSCmdlet.WriteError() - the latter being only available in advanced functions and scripts.
Note that this unexpectedly currently does not apply to the Write-Error cmdlet - see this GitHub issue
Note that both techniques invariably involve emitting an error.
Since it sounds like that's precisely what you're trying to avoid, you'll have to wait until the ability to set $? directly is implemented.
The decision to implement this ability has been made, but it's unclear when it will be implemented.
Workaround: Run cmd.exe and set whatever exit code you want before exiting the function. Example:
function Test-Function {
$cmd = Join-Path ([Environment]::GetFolderPath([Environment+SpecialFolder]::System)) "cmd.exe"
& $cmd /c exit 3
# $LASTEXITCODE will be set to 3
}

does AzCopy have an exit code which can be used to throw error in a PowerShell script

Like Robocopy (http://ss64.com/nt/robocopy-exit.html) does Azcopy have an exit code. If not what would be the best way to throw error for Azcopy when transfer was not successful inside a PowerShell script.
Exit code 0 means transferring succeeded, other exit codes means different kinds of error in AzCopy. Currently we haven't officially announced meaning of all error codes.

Dot-sourcing PowerShell script file and return code

Here's some PowerShell code:
test.ps1:
. C:\path\to\test2.ps1
exit 5
test2.ps1:
exit 7
Run test.ps1 from a standard command prompt however you like to run PowerShell scripts, then call:
echo %errorlevel%
The expected result is a return code of 7. This is the first exit command in the PowerShell script. The actual result, however, is a return code of 5. Obviously the included script was terminated but its return code was ignored and the calling script happily continued.
How can I really terminate a script and return a result code no matter how it was called?
Or alternatively, how should I call test2.ps1 so that its return code is passed on to the outside world?
Background: My build script is made with PowerShell and it includes module files for different tasks. One task currently fails and the build server didn't detect the error because my start build script still returned 0.
You should query $lastExitCode that would have nonzero value if the last script/program exited with failure. So, your sample's test1.ps1 should be like this:
. C:\path\to\test2.ps1
if ($lastexitcode -ne 0) { exit $lastexitcode}
exit 5

Detecting PowerShell script is executed with error

I have a PowerShell script:
...
Any-Command -ErrorCode Stop
...
Then I call this script from a bat script:
...
powershell myscript.ps1
...
Now I would like to know in the bat script if the called PowerShell script is stopped on error and not reached the end of the script. How to do it?
One way to do it would be to add a top level trap statement to your script, something like:
trap {
exit 1; # or whatever error code
}
Note: trap may be considered old fashioned (although I like it top-level), the other option would be a try-finally around your whole script.
So when Any-Command exits with an exception, the trap statement is executed and the script exits with error code 1. If you don't add this, Powershell will exit with error code 0 (after all Powershell ran just fine, although the script didn't).
You can then detect the error code in a bat script using something like:
powershell -noprofile -noninteractive -file <<your script>>
IF ERRORLEVEL 1 (echo ERROR) ELSE (echo OK)
pause
This will detect any error code of 1 or higher.
You can also use %ERRORLEVEL% but be wary that this may be overridden as an environment variable.
Note: if you're running your script in a nested runspace, you could consider using $host.SetShouldExit(1) to ensure the root host exits as well.
Just adding to the answer given by Marcus
I noticed that the trap code even hides the actual error. In my case I needed the actual error occurred. Just adding the modified code for the completion.
trap
{
write-error $("Error: " + $_.Exception.Message);
exit 1; # or whatever error code
}
More info at http://huddledmasses.org/trap-exception-in-powershell/

How do I get errors to propagate in the TeamCity PowerShell runner

I have a TeamCity 7 Build Configuration which is pretty much only an invocation of a .ps1 script using various TeamCity Parameters.
I was hoping that might be a simple matter of setting:
Script
File
Script File
%system.teamcity.build.workingDir%/Script.ps1
Script execution mode
Execute .ps1 script with "-File" argument
Script arguments
%system.teamcity.build.workingDir% -OptionB %BuildConfigArgument% %BuildConfigArg2%
And then I would expect:
if I mess up my arguments and the script won't start, the Build fails
if my Script.ps1 script throws, the Build fails
If the script exits with a non-0 Error Level I want the Build to Fail (maybe this is not idiomatic PS error management - should a .ps1 only report success by the absence of exceptions?)
The question: It just doesn't work. How is it supposed to work? Is there something I'm doing drastically wrong that I can fix by choosing different options?
As doc'd in the friendly TeamCity manual:
Setting Error Output to Error and adding build failure condition
In case syntax errors and exceptions are present, PowerShell writes them to stderr. To make TeamCity fail the build, set Error Output option to Error and add a build failure condition that will fail the build on any error output.
The keys to making this work is to change two defaults:
At the top level in the Build Failure Conditions, switch on an error message is logged by build runner:
In the [PowerShell] Build Step, Show advanced options and set Error output: Error
In 9.1 the following works (I wouldn't be surprised if it works for earlier versions too):
create a PowerShell Build Step with the default options
change the dropdown to say Script: Source code
Add a trap { Write-Error "Exception $_" ; exit 98 } at the top of the script
(Optional but more correct IMO for the kind of scripting that's appropriate for within TeamCity build scripts)
Show advanced options and switch on Options: Add -NoProfile argument
(Optional, but for me this should be the default as it renders more clearly as suggested by #Jamal Mavadat)
Show advanced options and switch on Error output: Error
(ASIDE #JetBrains: if the label was "Format stderr output as" it would be less misleading)
This covers the following cases:
Parse errors [bubble up as exceptions and stop execution immediately]
Exceptions [thrown directly or indirectly in your PS code show and trigger an exit code for TC to stop the build]
An explicit exit n in the script propagates out to the build (and fails it if non-zero)
There is an known bug in TeamCity that causes the behavior that the original poster noticed.
It is easy to work around, however.
At the end of your PowerShell script, add output indicating that the end of the script has been reached:
Echo "Packaging complete (end of script reached)"
Then, set up a new Build Failure Condition on your build to fail if the text you are echoing is NOT present in the output.
You're over-thinking things. Try this:
Script
File
Script File
Script.ps1
You don't need to give this a path - by default, it's relative to the checkout directory.
Script execution mode
Put script into PowerShell stdin with "-Command -" arguments
This is exactly what I use to run a bunch of powershell scripts within Teamcity.
Update
I missed the bit in the original post about having failures in the powershell script fail the build. Apologies!
I've solved that part of the puzzle in two different ways.
For regular powershell scripts
Wrap the main code block in a try...catch; if an exception occurs, return a non-zero integer value. For successful execution, return 0.
This convention of returning zero for success dates back a very long way in history - it's used by Unix/Linux systems, DOS, CP/M and more.
For PSake build scripts
Use a wrapper powershell script to invoke psake and directly set the result of the teamcity build by writing a response message to stdout.
At the start of the script, define a status message that represents failure:
$global:buildResult = "#teamcity[buildStatus status='FAILURE' text='It died.']
Within the psake script, update $global:buildResult to indicate success in a dedicated task that's run last of all.
$global:buildResult = "#teamcity[buildStatus status='SUCCESS' text='It lives.']
At the end of the wrapper script, output the status message
write-host $global:buildResult
If anything in the build script fails, that last task won't run, and the default message (indicating failure) will be output.
Either way, Teamcity will pick up on the message and set the build status appropriately.
An alternative to the accepted answer that works for me On TeamCity 9 (I don't like changing the 'Build Failure Conditions' option as it affects all build steps):-
I wanted PowerShell errors to fail the build step, but with a pretty message.
So I wanted to throw an error message AND return an error code.... try / catch / finally to the rescue.
EDIT for clarity: This script is supposed to fail. It is demonstrating that it is possible to throw an exception AND to return an exit code.
So you get both, the exit code for TeamCity to deal with, and, in my case, a nice clear debug message that shows where the issue was.
My demo script:
Try {
Write-Host "Demoing the finally bit"
# Make sure if anything goes wrong in the script we get an exception
$ErrorActionPreference = "Stop"
# This will fail and throw an exception (unless you add the file)
Get-Content IDontExist.txt
}
Catch
{
# Throwing like this gives a pretty error message in the build log
throw $_
# These give less pretty/helpful error messages
# Write-Host $_
# Write-Host $_.Exception.Message
}
Finally
{
# 69 because it's more funny than 1
exit(69)
}
If newer TeamCity versions are within your reach then it is worth checking out some of PowerShell build runner improvements.
In particular, changing Error Output from default warning to error may interest you.
Just praise the lawd you don't need to work with Jenkins.. Can't use the PowerShell step for similar issues. Instead we need to use a "cmd" step that calls the following magic wrapper that will fail the step on exception and exit codes:
%SystemRoot%\sysnative\WindowsPowerShell\v1.0\powershell.exe -ExecutionPolicy Bypass -NoLogo -NonInteractive -NoProfile -WindowStyle Hidden -Command "& { $ErrorActionPreference = 'Stop'; & 'path\to\script.ps1 -arg1 -arg2; EXIT $LASTEXITCODE }"
This has been superseded by options afforded by 9.x, but I'll leave it here as it definitely was bullet proof at the time and I couldn't find any other solution I liked better.
You could just do something that works. The following has been tested with
errors in the script bit
missing files
script exiting with non-0 ERRORLEVEL
In the TeamCity Powershell runner options, set it as follows:
Script File
Source code
Script source
$ErrorActionPreference='Stop'
powershell -NoProfile "Invoke-Command -ScriptBlock { `$errorActionPreference='Stop'; %system.teamcity.build.workingDir%/Script.ps1 %system.teamcity.build.workingDir% --OptionB %BuildConfigArgument% %BuildConfigArg2%; exit `$LastExitCode }"
(unwrapped version: powershell -NoProfile "Invoke-Command -ScriptBlock { $errorActionPreference='Stop'; %system.teamcity.build.workingDir%/Script.ps1 %system.teamcity.build.workingDir% --OptionB %BuildConfigArgument% %BuildConfigArg2%; exit$LastExitCode }"
Script execution mode
Put script into PowerShell stdin with "-Command -" arguments
Additional command line parameters
-NoProfile
I'm hoping against hope this isn't the best answer!
This checks the last error code and exits if is not 0.
If ($LASTEXITCODE -ne 0) {
Write-Host "The result was of the previous script was " $LASTEXITCODE
Exit $LASTEXITCODE
}
Powershell v2 atleast had an issue with the -File option messing up error codes. There is some details about how it messes up and stuff.
The answer is either switch to -Command option and/or wrap it with a bat file that checks the LastErrorCode and returns 1+ if its supposed to fail.
http://zduck.com/2012/powershell-batch-files-exit-codes/
Use something like this:
echo "##teamcity[buildStatus status='FAILURE' text='Something went wrong while executing the script...']";
For reference, take a look on Reporting Build Status from Teamcity