Yesterday we looked at stopping ASP.NET worker processes using PowerShell. However, I don't always want to stop the process by exe name or process ID, but by the name of the IIS application pool that the process is hosting. One way to do the job is with the iisapp.vbs script that ships with Windows Server.
PS>iisapp.vbs W3WP.exe PID: 4420 AppPoolId: aspNet20 W3WP.exe PID: 2572 AppPoolId: DefaultAppPool
How does iisapp.vbs figure this out? The script uses WMI to look at the command line that started w3wp.exe. There is a parameter (-ap) that specifies the application pool by name.
I beat my head against the wall trying to figure out a nice way to do this in PowerShell. Finally, I came across a post by abhishek, who wrote some script to find the services living inside svchost.exe, and everything became clear.
This is a function named get-aspnetwp. I can put this in my home configuration so it's always available. The function first gets a list of all processes named w3wp. The System.Diagnostics.Process objects in the list do not expose a property to inspect the command line, but we can use a WMI query to fetch the command line. A regular expression (-match) can parse out the application pool name (which always follows the -ap switch).
The function dynamically adds a property with the add-member cmdlet. The new property (AppPoolName) holds the application pool name. Ah, the power of a dynamic language! The last step in the function is to filter the list of objects against the incoming name parameter.
Now we can party...
PS> get-aspnetwp Handles NPM(K) PM(K) WS(K) VM(M) CPU(s) Id ProcessName ------- ------ ----- ----- ----- ------ -- ----------- 419 30 31128 3924 144 2.09 2572 w3wp 387 14 24580 7232 157 1.00 4420 w3wp
PS> get-aspnetwp | select Id, AppPoolName, StartTime | format-list Id : 4420 AppPoolName : aspNet20 StartTime : 7/10/2006 10:31:08 PM Id : 6064 AppPoolName : DefaultAppPool StartTime : 7/10/2006 11:56:57 PM
PS> get-aspnetwp DefaultAppPool | kill
The little function gives us object we can pipe to other cmdlets, like measure-object, where-object, select-object, etc. Sweetness.