The new Azure Invoice API enables Azure Subscription users with the appropriate role assignments to download and view current and past Invoices programmatically. Till now, this was only possible via the Azure Management Portal.

For Subscription users to be able to download these invoices, the account administrator needs to enable the “Access to Invoice” feature for the subscription. This is accomplished by navigating to the Subscription blade in the Azure Management Portal and selecting the Invoices tab as indicated in the following screen shot:

The following PowerShell function has been deployed as an Azure Automation Runbook. The function gets the latest Subscription invoice object, passes it to a memory stream by using the DownloadData(Uri) method of the System.Net.WebClient .NET Framework class.This method takes a URI as argument and returns a Byte array containing the downloaded resource. The method enables me the sending of the invoice as an email attachment without having to save the file to a host machine directory.

The Runbook can be scheduled to run monthly depending on the needs of the Subscription Admins.The email password credential is retrieved as an Azure Key vault secret. It is worth a mention that for now (July 2017), the Invoice API does not work for Enterprise Agreement Subscriptions. According to Microsoft, this will be made available in the near future.

#region create email creds and variables
<# 
.SYNOPSIS
   This function gets the latest Subscription invoice object and sends it as an email attachment.
.DESCRIPTION
  This function gets the latest Subscription invoice object and sends it as an email attachment.
  The function passes the invoice Byte object it to a memory stream by using the DownloadData(Uri) method of the System.Net.WebClient .NET Framework class.
  This method, takes a URI as argument and returns a Byte array containing the downloaded resource.
  The method enables the sending of the invoice as an email attachment without having to save the file to a host machine directory.
  It can be deployed as a runbook to an Azure Automation account. 
.PARAMETER SubscriptionName
        Subscription Name.
.PARAMETER ResourceGroupName
        ResourceGroupName.
.PARAMETER VaultName
        Key vault name that holds the credential secret.
.PARAMETER To
        To email address.
.EXAMPLE
       Send-AzureRmBillingInvoice
       
.FUNCTIONALITY
        PowerShell Language
/#>
Param(
$ResourceGroupName = "RGXavier",
$VaultName = "SampleKeyVault",
$smtpserver = "smtp.sendgrid.net",
$from = "admin@democonsults.com",
$to = "jane.doe@democonsults.com",
$SubscriptionName = "Trial Subscription",
$port = "587"
)

#endregion

#region
#Azure Logon
$connectionName = "AzureRunAsConnection"

try
{
    # Get the connection "AzureRunAsConnection "
    $servicePrincipalConnection=Get-AutomationConnection -Name $connectionName         

    "Logging in to Azure..."
    Add-AzureRmAccount `
        -ServicePrincipal `
        -TenantId $servicePrincipalConnection.TenantId `
        -ApplicationId $servicePrincipalConnection.ApplicationId `
        -CertificateThumbprint $servicePrincipalConnection.CertificateThumbprint 
}
catch {
    if (!$servicePrincipalConnection)
    {
        $ErrorMessage = "Connection $connectionName not found."
        throw $ErrorMessage
    } else{
        Write-Error -Message $_.Exception
        throw $_.Exception
            }
    }
Select-AzureRmSubscription -SubscriptionName $SubscriptionName

#endregion

#region email creds
$SendGridSecretName = "SendGridPassword"
$sendgridusername = "azure_eb0fc2179dd8f386d4f4e1f60dc2aee2@azure.com"
[securestring]$emailpassword = ((Get-AzureKeyVaultSecret -VaultName $VaultName -Name $SendGridSecretName).SecretValue)
$emailcred = (New-Object System.Management.Automation.PSCredential($sendgridusername, $emailpassword))

#endregion

#region
#Get Billing Invoice Object and create memory stream
$invoiceObject = Get-AzureRmBillingInvoice -Latest
$webClient = New-Object -TypeName System.Net.WebClient
[Byte[]] $invoice = $webClient.DownloadData($invoiceObject.DownloadUrl)

#Create memory stream
$memorystream = New-Object -TypeName System.IO.MemoryStream
$memorystream.Write($invoice,0,$invoice.Length)

#Set the position to the beginning of the stream
[void]$memorystream.Seek(0,'Begin')

#endregion

#region
#Prep Message Object
$message = New-Object System.Net.Mail.MailMessage 
$smtpClient = New-Object System.Net.Mail.smtpClient($smtpserver,$port)
$smtpClient.EnableSsl = $true
$smtpClient.Credentials = $emailcred
$recipient = New-Object System.Net.Mail.MailAddress($to)
$sender = New-Object System.Net.Mail.MailAddress($from)
$message.Sender = $sender
$message.From = $sender
$message.Subject = "AzureRm Billing Invoice"
$message.To.add($recipient)
$message.Body = "The AzureRm Billing Invoice is attached."

#endregion

#region
#Creat and add the attachment
 $contentType = New-Object -TypeName System.Net.Mime.ContentType -Property @{
 MediaType = [Net.Mime.MediaTypeNames+Application]::Octet
 Name = "Invoice.pdf"
 }
$attachment = New-Object Net.Mail.Attachment $memoryStream, $contentType
$message.Attachments.Add($attachment)

#endregion
             
#region
# Send Mail via SmtpClient 
$smtpClient.Send($message)

#endregion

#Get-Variable | Remove-Variable -ErrorAction SilentlyContinue
#cls