// apdebug.js
//
// This script takes an app pool name on the command line, iterates the running
// instances of w3wp.exe, and then launches the JIT debugger with a command line
// that instructs it to attach to the process that's hosting the specified
// app pool.
//
// Mike Woodring
// Bear Canyon Consulting LLC
// http://www.bearcanyon.com
// http://www.pluralsight.com/mike
//

// Parse/validate the command line (a single app pool name argument is required).
//
var targetAppPool = (WScript.Arguments.Length == 1 ? WScript.Arguments(0) : null);

if( targetAppPool == null )
{
    WScript.Echo("You must specify an app pool name on the command line.");
    WScript.Quit();
}

// Enumerate the running instances of w3wp.exe.
//
var wmi = GetObject("winmgmts://./root/cimv2");
var w3wpInstances = wmi.ExecQuery("SELECT * FROM Win32_Process WHERE Name = 'w3wp.exe'");

if( w3wpInstances.Count == 0)
{
    WScript.Echo("No running instances of w3wp.exe found.");
    WScript.Quit();
}

// Setup a regular expression that can parse the -ap command line switch
// for an instance of w3wp.exe.  VBScript's regex support doesn't include
// named capture, but it does support capturing groups which can be referred
// to by index.
//
var regexp = /-ap\s+\"([^.]+)\"/i;

// Iterate over the collection of w3wp.exe processes identified above,
// using the regex to extract the contents of the -ap (app pool)
// command line option.
//
WScript.Echo("Active app pools...");

var targetPID = 0;
var targetAppPoolLowerCase = targetAppPool.toLowerCase();
var enumerator = new Enumerator(w3wpInstances);

for( enumerator.moveFirst(); !enumerator.atEnd(); enumerator.moveNext() )
{
    var w3wp = enumerator.item();
    var matches = regexp.exec(w3wp.CommandLine);

    if( matches.length == 2 )
    {
        // Successfully parsed the -ap command line for the running
        // instance of w3wp.exe being operated on.  Perform a case-insensitive
        // string comparison of that app pool name with the app pool name
        // passed to this script's command line.  If we've found a match,
        // make a note of this w3wp's process ID (and original-case app pool name).
        //
        var appPoolName = matches[1];
        
        WScript.Echo("  " + appPoolName + " (" + w3wp.ProcessId + ")");
        
        if( appPoolName.toLowerCase() == targetAppPoolLowerCase )
        {
            // This is instances of w3wp.exe we want to attach the
            // debugger to.  So make a note.
            //
            targetPID = w3wp.ProcessId;
            targetAppPool = appPoolName;
        }
    }
}

WScript.Echo();

if( targetPID != 0 )
{
    // Found it - debug it.
    //
    WScript.Echo("Launching debugger for '" + targetAppPool + "' (" + targetPID + ")...");
    var vsjitCommandLine = "vsjitdebugger -p " + targetPID;
    var shell = WScript.CreateObject("WScript.Shell");
    shell.Run(vsjitCommandLine, 1, false);
}
else
{
    WScript.Echo("The app pool specified (" + targetAppPool + ") is not running.");
}