feat: add configuration checking

internal/checkConfig.go

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2024 Jonas Kaninda
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package pkg
+
+import (
+	"fmt"
+	"github.com/jkaninda/goma-gateway/util"
+	"gopkg.in/yaml.v3"
+	"log"
+	"os"
+)
+
+func CheckConfig(fileName string) error {
+	if !util.FileExists(fileName) {
+		return fmt.Errorf("config file not found: %s", fileName)
+	}
+	buf, err := os.ReadFile(fileName)
+	if err != nil {
+		return err
+	}
+	c := &GatewayConfig{}
+	err = yaml.Unmarshal(buf, c)
+	if err != nil {
+		return fmt.Errorf("parsing the configuration file %q: %w", fileName, err)
+	}
+	gateway := &GatewayServer{
+		ctx:         nil,
+		version:     c.Version,
+		gateway:     c.GatewayConfig,
+		middlewares: c.Middlewares,
+	}
+	for index, route := range gateway.gateway.Routes {
+		if len(route.Name) == 0 {
+			log.Printf("Warning: route name is empty, index: [%d]", index)
+		}
+		if route.Destination == "" && len(route.Backends) == 0 {
+			log.Printf("Error: no destination or backends specified for route: %s | index: [%d] \n", route.Name, index)
+		}
+	}
+
+	//Check middleware
+	for index, mid := range c.Middlewares {
+		if util.HasWhitespace(mid.Name) {
+			log.Printf("Warning: Middleware contains whitespace: %s | index: [%d], please remove whitespace characters\n", mid.Name, index)
+		}
+	}
+
+	log.Printf("Routes count=%d Middlewares count=%d\n", len(gateway.gateway.Routes), len(gateway.middlewares))
+
+	return nil
+
+}