GetOvsPortForContIface should not return error if iface not found (#305)

Currently the function returns '"",false, err' in case if interface
not found.

The signature and usage of this function assume that the
function should not return and error in case if interface not
found.

Fix the function to return '"", false, nil' in case if the interface
not found.

This change fixes CmdDel for scenario when CmdDel is called
after failed CmdAdd or when port was manually removed from the ovs.

Signed-off-by: Yury Kulazhenkov <[email protected]>

Author: ykulazhenkov

pkg/ovsdb/ovsdb.go

@@ -33,6 +33,10 @@ const (
 	ovsTable    = "Open_vSwitch"
 )
 
+var (
+	errObjectNotFound = errors.New("object not found")
+)
+
 // Bridge defines an object in Bridge table
 type Bridge struct {
 	UUID string `ovsdb:"_uuid"`
@@ -631,6 +635,9 @@ func (ovsd *OvsDriver) GetOvsPortForContIface(contIface, contNetnsPath string) (
 	colums := []string{"name", "external_ids"}
 	port, err := ovsd.findByCondition("Port", condition, colums)
 	if err != nil {
+		if errors.Is(err, errObjectNotFound) {
+			return "", false, nil
+		}
 		return "", false, err
 	}
 
@@ -745,7 +752,7 @@ func (ovsd *OvsDriver) findByCondition(table string, condition ovsdb.Condition,
 	}
 
 	if len(operationResult.Rows) != 1 {
-		return nil, fmt.Errorf("failed to find object from table %s", table)
+		return nil, fmt.Errorf("%w in the table %s", errObjectNotFound, table)
 	}
 
 	return operationResult.Rows[0], nil