libnet/d/remote: replace errorWithRollback

Use defer funcs instead.

For no apparant reasons, a few error cases in the Join method were not
triggering a rollback. This is now fixed.

Signed-off-by: Albin Kerouanton <albinker@gmail.com>

libnetwork/drivers/remote/driver.go

@@ -172,7 +172,7 @@ func (d *driver) DeleteNetwork(nid string) error {
 	return d.call("DeleteNetwork", &api.DeleteNetworkRequest{NetworkID: nid}, &api.DeleteNetworkResponse{})
 }
 
-func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo, epOptions map[string]interface{}) error {
+func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo, epOptions map[string]interface{}) (retErr error) {
 	if ifInfo == nil {
 		return errors.New("must not be called with nil InterfaceInfo")
 	}
@@ -199,6 +199,16 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 		return err
 	}
 
+	defer func() {
+		if retErr != nil {
+			if err := d.DeleteEndpoint(nid, eid); err != nil {
+				retErr = fmt.Errorf("%w; failed to roll back: %w", err, retErr)
+			} else {
+				retErr = fmt.Errorf("%w; rolled back", retErr)
+			}
+		}
+	}()
+
 	inIface, err := parseInterface(res)
 	if err != nil {
 		return err
@@ -210,31 +220,23 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 
 	if inIface.MacAddress != nil {
 		if err := ifInfo.SetMacAddress(inIface.MacAddress); err != nil {
-			return errorWithRollback(fmt.Sprintf("driver modified interface MAC address: %v", err), d.DeleteEndpoint(nid, eid))
+			return fmt.Errorf("driver modified interface MAC address: %v", err)
 		}
 	}
 	if inIface.Address != nil {
 		if err := ifInfo.SetIPAddress(inIface.Address); err != nil {
-			return errorWithRollback(fmt.Sprintf("driver modified interface address: %v", err), d.DeleteEndpoint(nid, eid))
+			return fmt.Errorf("driver modified interface address: %v", err)
 		}
 	}
 	if inIface.AddressIPv6 != nil {
 		if err := ifInfo.SetIPAddress(inIface.AddressIPv6); err != nil {
-			return errorWithRollback(fmt.Sprintf("driver modified interface address: %v", err), d.DeleteEndpoint(nid, eid))
+			return fmt.Errorf("driver modified interface address: %v", err)
 		}
 	}
 
 	return nil
 }
 
-func errorWithRollback(msg string, err error) error {
-	rollback := "rolled back"
-	if err != nil {
-		rollback = "failed to roll back: " + err.Error()
-	}
-	return fmt.Errorf("%s; %s", msg, rollback)
-}
-
 func (d *driver) DeleteEndpoint(nid, eid string) error {
 	deleteRequest := &api.DeleteEndpointRequest{
 		NetworkID:  nid,
@@ -256,7 +258,7 @@ func (d *driver) EndpointOperInfo(nid, eid string) (map[string]interface{}, erro
 }
 
 // Join method is invoked when a Sandbox is attached to an endpoint.
-func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo, options map[string]interface{}) error {
+func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo, options map[string]interface{}) (retErr error) {
 	join := &api.JoinRequest{
 		NetworkID:  nid,
 		EndpointID: eid,
@@ -271,10 +273,20 @@ func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo,
 		return err
 	}
 
+	defer func() {
+		if retErr != nil {
+			if err := d.Leave(nid, eid); err != nil {
+				retErr = fmt.Errorf("%w; failed to roll back: %w", err, retErr)
+			} else {
+				retErr = fmt.Errorf("%w; rolled back", retErr)
+			}
+		}
+	}()
+
 	ifaceName := res.InterfaceName
 	if iface := jinfo.InterfaceName(); iface != nil && ifaceName != nil {
 		if err := iface.SetNames(ifaceName.SrcName, ifaceName.DstPrefix); err != nil {
-			return errorWithRollback(fmt.Sprintf("failed to set interface name: %s", err), d.Leave(nid, eid))
+			return fmt.Errorf("failed to set interface name: %s", err)
 		}
 	}
 
@@ -284,15 +296,15 @@ func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo,
 			return fmt.Errorf(`unable to parse Gateway "%s"`, res.Gateway)
 		}
 		if jinfo.SetGateway(addr) != nil {
-			return errorWithRollback(fmt.Sprintf("failed to set gateway: %v", addr), d.Leave(nid, eid))
+			return fmt.Errorf("failed to set gateway: %v", addr)
 		}
 	}
 	if res.GatewayIPv6 != "" {
 		if addr = net.ParseIP(res.GatewayIPv6); addr == nil {
 			return fmt.Errorf(`unable to parse GatewayIPv6 "%s"`, res.GatewayIPv6)
 		}
 		if jinfo.SetGatewayIPv6(addr) != nil {
-			return errorWithRollback(fmt.Sprintf("failed to set gateway IPv6: %v", addr), d.Leave(nid, eid))
+			return fmt.Errorf("failed to set gateway IPv6: %v", addr)
 		}
 	}
 	if len(res.StaticRoutes) > 0 {
@@ -302,7 +314,7 @@ func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo,
 		}
 		for _, route := range routes {
 			if jinfo.AddStaticRoute(route.Destination, route.RouteType, route.NextHop) != nil {
-				return errorWithRollback(fmt.Sprintf("failed to set static route: %v", route), d.Leave(nid, eid))
+				return fmt.Errorf("failed to set static route: %v", route)
 			}
 		}
 	}