Retry VM Delete without Force if Bad Request

Azure Stack returns a 400 error when trying to delete a VM with
the force flag and the error message suggests retrying without
the flag.

Author: patrickdillon

azure/errors.go

@@ -34,6 +34,12 @@ func ResourceNotFound(err error) bool {
 	return errors.As(err, &rerr) && rerr.StatusCode == http.StatusNotFound
 }
 
+// BadRequest parses an error to check if it its status code is Bad Request (400).
+func BadRequest(err error) bool {
+	var rerr *azcore.ResponseError
+	return errors.As(err, &rerr) && rerr.StatusCode == http.StatusBadRequest
+}
+
 // VMDeletedError is returned when a virtual machine is deleted outside of capz.
 type VMDeletedError struct {
 	ProviderID string

azure/services/virtualmachines/client.go

@@ -109,14 +109,21 @@ func (ac *AzureClient) CreateOrUpdateAsync(ctx context.Context, spec azure.Resou
 // request to Azure and if accepted without error, the func will return a Poller which can be used to track the ongoing
 // progress of the operation.
 func (ac *AzureClient) DeleteAsync(ctx context.Context, spec azure.ResourceSpecGetter, resumeToken string) (poller *runtime.Poller[armcompute.VirtualMachinesClientDeleteResponse], err error) {
-	ctx, _, done := tele.StartSpanWithLogger(ctx, "virtualmachines.AzureClient.Delete")
+	ctx, log, done := tele.StartSpanWithLogger(ctx, "virtualmachines.AzureClient.Delete")
 	defer done()
 
 	forceDelete := ptr.To(true)
 	opts := &armcompute.VirtualMachinesClientBeginDeleteOptions{ResumeToken: resumeToken, ForceDeletion: forceDelete}
 	poller, err = ac.virtualmachines.BeginDelete(ctx, spec.ResourceGroupName(), spec.ResourceName(), opts)
 	if err != nil {
-		return nil, err
+		if azure.BadRequest(err) {
+			log.Info("Failed to Begin VM Delete with Force Deletion, retrying without the force flag")
+			opts.ForceDeletion = ptr.To(false)
+			poller, err = ac.virtualmachines.BeginDelete(ctx, spec.ResourceGroupName(), spec.ResourceName(), opts)
+		}
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	ctx, cancel := context.WithTimeout(ctx, ac.apiCallTimeout)