Resolve "Improve token usage for users"

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Resolves to #378

controller/northbound/server/auth.go

@@ -183,21 +183,9 @@ func (s AuthServer) handleLogout(ctx context.Context, userName string) error {
 			return err
 		}
 
-		storedTokens := storedUser.GetTokens()
-		foundToken := false
-		for _, storedToken := range storedTokens {
-			if storedToken == token {
-				err := storedUser.RemoveToken(token)
-				if err != nil {
-					return status.Errorf(codes.Aborted, "error checking match of token provied for user")
-				}
-				foundToken = true
-				break
-			}
-		}
-
-		if !foundToken {
-			return status.Errorf(codes.Aborted, "missing match of token provied for user")
+		err = removeTokenFromUserIfExists(storedUser, token)
+		if err != nil {
+			status.Errorf(codes.Aborted, "Error removing token from user, it was either already logged out or otherwise not found")
 		}
 
 		err = s.userService.Update(&rbac.User{UserID: storedUser.ID(),
@@ -227,3 +215,17 @@ func addTokenAndEnsureTokenLimit(userToUpdate rbacInterfaces.User, token string)
 	}
 	return nil
 }
+
+func removeTokenFromUserIfExists(storedUser rbacInterfaces.User, token string) error {
+	storedTokens := storedUser.GetTokens()
+	for _, storedToken := range storedTokens {
+		if storedToken == token {
+			err := storedUser.RemoveToken(token)
+			if err != nil {
+				return errors.New("could not remove token from user")
+			}
+			return nil
+		}
+	}
+	return errors.New("token not found for user")
+}