How can I determine if a session is active?

[halr9000]

When writing scripts, I want to check at the top whether or not a session exists, and if not, prompt a user for credentials and server name in order to create one. I'd like to be able to do something like this:

if ($ViSession) { get-vm }

or

if (!Get-ViSession) { 
  Get-ViServer -server (read-host "Enter server name") 
}

So how will we be able to do this?

[admin]

You can't tell if a session is still valid strictly from the client

since session management is owner by the server. Sessions may time out

or be killed by administrators. So the only way to tell is to initiate

a request to the server. We might want to add this as something we

explicitly support but given what you currently have available, you

could try something like:

function test-viserver {
  $needSession = $false

  $session = $null
  trap {
    Set-Variable needSession $true -Scope 1
    continue
  }

  Get-OSCustomizationSpec -name __foo__
  if ($needSession -eq $true) {
    $session = Get-VIServer -Server (Read-Host "Enter server name")

    if ($session -ne $null) {
      $needSession = $false
    }   
  }

  return !$needSession
}

And use it like this:

PS C:\> . test-viserver
Enter server name: junk
False
PS C:\> . test-viserver
Enter server name: server
True
PS C:\> . test-viserver
True

[admin]

I give up on trying to format that thing. Anyway, that should work if you insert the appropriate line breaks.

[halr9000]

The trick is #your code here

Remove the spaces between the {}'s and the keyword.

[admin]

cool. thanks.

[halr9000]

So the only way to tell is to initiate

a request to the server. We might want to add this as something we

explicitly support

Yeah...a Test-ViSession cmdlet could query the server, that would be cool.

[admin · Accepted solution]

Yeah...a Test-ViSession cmdlet could query the server, that would be cool.

Sure. Until then, I think this fits the bill. It's effectively doing the same thing.