如何使Powershell等待内部命令完成？

Question

I have a PS script that creates a new app pool and then changes it's .Net version to 4.0:

new-webapppool -name 'ABC' -force
Set-ItemProperty IIS:\AppPools\ABC managedRuntimeVersion v4.0

This script is run on an AWS EC2 instance non-interactively as part of a Cloudformation stack creation.

My problem is that randomly I will get the following error:

Set-ItemProperty : Cannot find path 'IIS:\AppPools\ABC' because it does not exist.

Do I need some additional logic to force the PS script to wait until the "new-webapppool" command completes? If so, what is the correct way?

From my Googling I am finding that one should only have to explicitly tell it to wait if an external program (.exe, etc) is being executed. Thoughts?

Answer 1

You can add a while loop, which will wait until the previous command has fully replicated to your connected cloud instance. I feel like this is a side effect of cloud.

new-webapppool -name 'ABC' -force

while (!(get-childitem IIS:\AppPools\ABC -errorAction SilentlyContinue)) {
     start-sleep 5 # recheck every 5 seconds
}

Set-ItemProperty IIS:\AppPools\ABC managedRuntimeVersion v4.0

You can also store your -name as a variable and use the same variable in the while loop. That way you don't have to update the String in multiple places for each subsequent run of the code.