BugFix: Better error handling for azure

Azure didn't handle error handling for cases when NIC wasn't created properly. This commit fixes that by embedding appropriate error messages when errors occur in Azure driver machine creation logic.

Author: prashanth26

pkg/driver/driver_azure.go

@@ -76,6 +76,9 @@ func (d *AzureDriver) Create() (string, string, error) {
 		"",
 	)
 	err = onErrorFail(err, fmt.Sprintf("subnetClient.Get failed for subnet %q", subnet.Name))
+	if err != nil {
+		return "Error", "Error", err
+	}
 
 	enableIPForwarding := true
 	nicParameters := network.Interface{
@@ -94,11 +97,20 @@ func (d *AzureDriver) Create() (string, string, error) {
 		},
 		Tags: &tagList,
 	}
-	cancel := make(chan struct{})
+
+	var cancel chan struct{}
+
 	_, errChan := interfacesClient.CreateOrUpdate(resourceGroup, nicName, nicParameters, cancel)
 	err = onErrorFail(<-errChan, fmt.Sprintf("interfacesClient.CreateOrUpdate for NIC '%s' failed", nicName))
+	if err != nil {
+		return "Error", "Error", err
+	}
+
 	nicParameters, err = interfacesClient.Get(resourceGroup, nicName, "")
 	err = onErrorFail(err, fmt.Sprintf("interfaces.Get for NIC '%s' failed", nicName))
+	if err != nil {
+		return "Error", "Error", err
+	}
 
 	vm := compute.VirtualMachine{
 		Location: &location,
@@ -155,9 +167,13 @@ func (d *AzureDriver) Create() (string, string, error) {
 		},
 		Tags: &tagList,
 	}
+
+	cancel = nil
 	_, errChan = vmClient.CreateOrUpdate(resourceGroup, vmName, vm, cancel)
 	err = onErrorFail(<-errChan, "createVM failed")
-	//glog.Infof("Created machine '%s' successfully\n", vmName)
+	if err != nil {
+		return "Error", "Error", err
+	}
 
 	return d.encodeMachineID(location, vmName), vmName, err
 }