created setup and backend structure

backend/config.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+var CONFIG_PATH = "config.yaml"
+
+type ConfigYaml struct {
+	LogLevel string `yaml:"log_level"`
+	Database struct {
+		Host     string `yaml:"host"`
+		User     string `yaml:"user"`
+		Password string `yaml:"password"`
+		Database string `yaml:"database"`
+	} `yaml:"database"`
+	ClientSession struct {
+		JwtSignature string `yaml:"jwt_signature"`
+		Expire       string `yaml:"expire"`
+	} `yaml:"client_session"`
+}
+
+type CacheConfig struct {
+	Expiration time.Duration
+	Purge      time.Duration
+}
+
+var config ConfigYaml
+
+func loadConfig() ConfigYaml {
+	config := ConfigYaml{}
+
+	yamlFile, err := os.ReadFile(CONFIG_PATH)
+	if err != nil {
+		panic(fmt.Sprintf("Error opening config-file: %v", err))
+	}
+
+	reader := bytes.NewReader(yamlFile)
+
+	dec := yaml.NewDecoder(reader)
+	dec.KnownFields(true)
+	err = dec.Decode(&config)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error parsing config-file: %v", err)
+		os.Exit(1)
+	}
+
+	return config
+}
+
+func writeConfig() {
+	buf := bytes.Buffer{}
+	enc := yaml.NewEncoder(&buf)
+	enc.SetIndent(2)
+	// Can set default indent here on the encoder
+	if err := enc.Encode(&config); err != nil {
+		panic(err)
+	} else {
+		if err := os.WriteFile(CONFIG_PATH, buf.Bytes(), 0644); err != nil {
+			panic(err)
+		}
+	}
+}
+
+func init() {
+	config = loadConfig()
+}