started working on the backend

backend/pkg/config/config.go

@@ -0,0 +1,95 @@
+package config
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/johannesbuehl/golunteer/backend/pkg/lib"
+	"github.com/rs/zerolog"
+	"gopkg.in/yaml.v3"
+)
+
+type ReservationConfig struct {
+	Expiration time.Duration
+}
+
+type ConfigStruct struct {
+	ConfigYaml
+	LogLevel      zerolog.Level
+	SessionExpire time.Duration
+}
+
+var Config ConfigStruct
+
+type Payload struct {
+	jwt.RegisteredClaims
+	CustomClaims map[string]any
+}
+
+func (config ConfigStruct) SignJWT(val any) (string, error) {
+	valMap, err := lib.StrucToMap(val)
+
+	if err != nil {
+		return "", err
+	}
+
+	payload := Payload{
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(config.SessionExpire)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+		},
+		CustomClaims: valMap,
+	}
+
+	t := jwt.NewWithClaims(jwt.SigningMethodHS256, payload)
+
+	return t.SignedString([]byte(config.ClientSession.JwtSignature))
+}
+
+func loadConfig() ConfigStruct {
+	Config := ConfigYaml{}
+
+	yamlFile, err := os.ReadFile("config.yaml")
+	if err != nil {
+		panic(fmt.Sprintf("Error opening config-file: %q", 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)
+	}
+
+	if logLevel, err := zerolog.ParseLevel(Config.LogLevel); err != nil {
+		panic(fmt.Errorf("can't parse log-level: %v", err))
+	} else {
+		var configStruct ConfigStruct
+
+		// parse the durations
+		if session_expire, err := time.ParseDuration(Config.ClientSession.Expire); err != nil {
+			log.Fatalf(`Error parsing "client_session.expire": %v`, err)
+
+			// parse the templates
+		} else {
+			configStruct = ConfigStruct{
+				ConfigYaml:    Config,
+				LogLevel:      logLevel,
+				SessionExpire: session_expire,
+			}
+		}
+
+		return configStruct
+	}
+}
+
+func init() {
+	Config = loadConfig()
+}