PowerShell Script | Backup Azure SQL MI DB to Blob

#Install-Module dbatools
#Install-Module -Name Az -AllowClobber -Scope AllUsers


param(
[string]$server = ".", 
[string] $Database ,
[string] $subscription,
[string] $ResourceGroupName,
[string] $StorageAccount,
[string] $container,
[string] $BackupfileName = "1"
)
#Get-AzSubscription | Format-Table
#Set-AzContext "Rizwan_Internal_1000"
#$subscription = 'Rizwan_Internal_1000'
Select-AzSubscription -Subscription $subscription
Get-AzContext
#$server = "tcp:sql1243.public.b955f902d673.database.windows.net,3342"
#$Database = "Pubs"
$server_Login = (Get-Credential)

#Setting up backup file name
if ($BackupfileName -ne "1")
{
    $BackupfileName = $BackupfileName
}
else {
    $dt = Get-Date -Format yyyyMMdd_HHmmss
    $BackupfileName = $Database + "_$dt" + ".bak"
}

$BlobStorageURL = "https://$StorageAccount.blob.core.windows.net/$container"
Write-Host $BlobStorageURL, $Server, $Database, $subscription

$StorageAccount = Get-AzStorageAccount -ResourceGroupName $ResourceGroupName -Name $StorageAccount
$ctx = $storageAccount.Context


#checking if credential already exist or need be created
$SASCredential = Get-DbaCredential -SqlInstance $server -SqlCredential $server_Login 
$SQLMI = Connect-DbaInstance -SqlInstance $server -SqlCredential $server_Login

$sas = (New-AzStorageAccountSASToken -Service Blob -ResourceType Object -Permission "rwdl" -Context $ctx).TrimStart('?')
$serverCred = New-DbaCredential -SqlInstance $SQLMI `
                       -Name $BlobStorageURL `
                       -Identity "SHARED ACCESS SIGNATURE" `
                       -SecurePassword (ConvertTo-SecureString $sas -AsPlainText -Force) `
                       -Force
write-host "Credential recreated"
<#
if ($SASCredential.Name -eq $BlobStorageURL)
{
     
    write-host "Credential already exists, skipping this step"
}
Else {
    $sas = (New-AzStorageAccountSASToken -Service Blob -ResourceType Object -Permission "rwdl" -Context $ctx).TrimStart('?')
    $serverCred = New-DbaCredential -SqlInstance $SQLMI `
                           -Name $BlobStorageURL `
                           -Identity "SHARED ACCESS SIGNATURE" `
                           -SecurePassword (ConvertTo-SecureString $sas -AsPlainText -Force) `
                           -Force
                           
    write-host "Credential does NOT and it has been created"
}
#>
Backup-DbaDatabase -SqlInstance $SQLMI -Database $Database `
    -AzureBaseUrl $BlobStorageURL `
    -BackupFileName $BackupfileName `
    -Type Full -Checksum -CopyOnly -CompressBackup -Verbose
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