How to detect if Azure Powershell session has expired?

Azure RM but this will check if there is an active account otherwise throw up a prompt.

if ([string]::IsNullOrEmpty($(Get-AzureRmContext).Account)) {Login-AzureRmAccount}

Cheers

You need to run Get-AzureRmContext and check if the Account property is populated. In the latest version of AzureRM, Get-AzureRmContext doesn't raise error (the error is raised by cmdlets that require active session). However, apparently in some other versions it does.

This works for me:

function Login
{
    $needLogin = $true
    Try 
    {
        $content = Get-AzureRmContext
        if ($content) 
        {
            $needLogin = ([string]::IsNullOrEmpty($content.Account))
        } 
    } 
    Catch 
    {
        if ($_ -like "*Login-AzureRmAccount to login*") 
        {
            $needLogin = $true
        } 
        else 
        {
            throw
        }
    }

    if ($needLogin)
    {
        Login-AzureRmAccount
    }
}

If you are using the new Azure PowerShell API, it's much simpler

function Login($SubscriptionId)
{
    $context = Get-AzContext

    if (!$context -or ($context.Subscription.Id -ne $SubscriptionId)) 
    {
        Connect-AzAccount -Subscription $SubscriptionId
    } 
    else 
    {
        Write-Host "SubscriptionId '$SubscriptionId' already connected"
    }
}