Asynchronously call powershell script from ASP.NET

Question

Trying to asynchronously call a powershell script within an ASP.NET IHttHandler, I stumbled accross the example on http://msdn.microsoft.com/en-us/library/ee706580(v=vs.85).aspx. My own code looks like this:

using (PowerShell powershell = PowerShell.Create()) {
    powershell.AddScript("1..10 | foreach {$_ ; start-sleep -milli 500}");

    PSDataCollection<PSObject> output = new PSDataCollection<PSObject>();

    output.DataAdded += delegate(object sender, DataAddedEventArgs e) {
        PSDataCollection<PSObject> myp = (PSDataCollection<PSObject>)sender;
        Collection<PSObject> results = myp.ReadAll();
    };

    powershell.InvocationStateChanged += delegate(object sender, PSInvocationStateChangedEventArgs e) {
        if (e.InvocationStateInfo.State == PSInvocationState.Completed) {
            // Clean up
        }
    };

    IAsyncResult asyncResult = powershell.BeginInvoke<PSObject, PSObject>(null, output);
}

Unfortunately, the powershell script is obviously not being executed. No powershell process shows up in the task manager.

I set break points withing the DataAdded and IncovationStateChanged handlers. The first one never gets called, the second one shows, that e.InvocationStateInfo.State never becomes Completed but ends with Stopped.

What am I doing wrong?

This approach doesn't spin up a PowerShell process. You have the PowerShell engine running in-process. By using BeginInvoke, that same in-process engine executes your request async on another thread and not in another process. At some point, you should call EndInvoke(). — Keith Hill
– Keith Hill, Commented Mar 26, 2014 at 15:52
I guess you're refering to my remark, that no powershell process shows up? Still, the script isn't executed. InvocationStateInfo.State changes from running immediately to Stopping, although the script is expected to run 2:30 minutes. — sk904861
– sk904861, Commented Mar 26, 2014 at 16:11

Keith Hill · Accepted Answer · 2014-03-26 17:39:02Z

This works in a console app:

using (PowerShell powershell = PowerShell.Create())
{
    powershell.AddScript("1..10 | foreach {$_ ; start-sleep -milli 500}");

    var output = new PSDataCollection<PSObject>();

    output.DataAdded += delegate(object sender, DataAddedEventArgs e)
    {
        Console.WriteLine(output[e.Index]);
        var myp = (PSDataCollection<PSObject>)sender;
        Collection<PSObject> results = myp.ReadAll();
    };

    powershell.InvocationStateChanged += delegate(object sender, PSInvocationStateChangedEventArgs e)
    {
        if (e.InvocationStateInfo.State == PSInvocationState.Completed)
        {
            // Clean up
        }
    };

    IAsyncResult asyncResult = powershell.BeginInvoke<PSObject, PSObject>(null, output);

    asyncResult.AsyncWaitHandle.WaitOne();
}

If you don't somehow synchronize or comeback later and wait for the invoke to finish, the PowerShell engine shuts down because powershell.Dispose() gets called as it falls out of your using {} scope.

Collectives™ on Stack Overflow

Asynchronously call powershell script from ASP.NET

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related