added overwrite if rule exists

AddTransportRule/run.ps1

@@ -6,17 +6,28 @@ param($Request, $TriggerMetadata)
 $APIName = $TriggerMetadata.FunctionName
 Write-LogMessage -user $request.headers.'x-ms-client-principal' -API $APINAME  -message "Accessed this API" -Sev "Debug"
 
-$RequestParams = $Request.Body.PowerShellCommand | ConvertFrom-Json | Select-Object -Property * -ExcludeProperty GUID
+$RequestParams = $Request.Body.PowerShellCommand | ConvertFrom-Json | Select-Object -Property * -ExcludeProperty GUID, Comments
 
 $Tenants = ($Request.body | Select-Object Select_*).psobject.properties.value
 $Result = foreach ($Tenantfilter in $tenants) {
+    $Existing = New-ExoRequest -ErrorAction SilentlyContinue -tenantid $Tenantfilter -cmdlet "Get-TransportRule" -useSystemMailbox $true | Where-Object -Property Identity -EQ $RequestParams.name
     try {
-        $GraphRequest = New-ExoRequest -tenantid $Tenantfilter -cmdlet "New-TransportRule" -cmdParams $RequestParams
-        "Successfully created transport rule for $tenantfilter."
+        if ($Existing) {
+            Write-Host "Found existing"
+            $RequestParams | Add-Member -NotePropertyValue $RequestParams.name -NotePropertyName Identity
+            $GraphRequest = New-ExoRequest -tenantid $Tenantfilter -cmdlet "Set-TransportRule" -cmdParams ($RequestParams | Select-Object -Property * -ExcludeProperty UseLegacyRegex) -useSystemMailbox $true
+            "Successfully set transport rule for $tenantfilter."
+        }
+        else {
+            Write-Host "Creating new"
+            $GraphRequest = New-ExoRequest -tenantid $Tenantfilter -cmdlet "New-TransportRule" -cmdParams $RequestParams -useSystemMailbox $true
+            "Successfully created transport rule for $tenantfilter."
+        }
+
         Write-LogMessage -API $APINAME -tenant $tenantfilter -message "Created transport rule for $($tenantfilter)" -sev Debug
     }
     catch {
-        "Could not create created transport rule for $($tenantfilter): $($_.Exception.message)"
+        "Could not create transport rule for $($tenantfilter): $($_.Exception.message)"
     }
 }