style: logger formatting

main.go

@@ -2,6 +2,9 @@ package main
 
 import (
 	"fmt"
+	"log/slog"
+	"os"
+	"strings"
 
 	"realdnydns/pkg/config"
 	"realdnydns/pkg/dnsProvider"
@@ -15,48 +18,84 @@ import (
 )
 
 func main() {
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+		Level: slog.LevelInfo,
+	}))
+
 	configClient := config.Config{}
 	err := configClient.Load("config.yaml")
 	if err != nil {
+		logger.Error("Failed to load config file", slog.String("error", err.Error()))
 		panic(err)
 	}
 
+	if configClient.LogLevel != "" {
+		logger = slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+			Level: slog.Level(config.LogLevelMap[strings.ToLower(configClient.LogLevel)]),
+		}))
+	}
+
 	var externalIpProvider externalIpProvider.ExternalIpProvider
 	switch configClient.ExternalIPProvider.Type {
 	case "plain":
+		logger.Info("Using plain external IP provider", slog.String("external_ip_provider", "plain"))
+
 		var plainConfig plainExternalIpProvider.PlainExternalIpProviderConfig
 		err := configClient.ExternalIPProvider.ProviderConfig.Decode(&plainConfig)
 		if err != nil {
+			logger.Error("Failed to create config",
+				slog.String("external_ip_provider", "plain"),
+				slog.String("error", err.Error()),
+			)
 			panic(err)
 		}
 
 		externalIpProvider, err = plainExternalIpProvider.New(plainConfig)
 		if err != nil {
+			logger.Error("Failed to create plain external IP provider",
+				slog.String("external_ip_provider", "plain"),
+				slog.String("error", err.Error()),
+			)
 			panic(err)
 		}
 	default:
+		logger.Error("Unknown external IP provider", slog.String("external_ip_provider", configClient.ExternalIPProvider.Type))
 		panic(fmt.Errorf("unknown external IP provider: %s", configClient.ExternalIPProvider.Type))
 	}
 
 	var dnsProvider dnsProvider.DNSProvider
 	switch configClient.DNSProvider.Type {
 	case "ionos":
+		logger.Info("Using IONOS DNS provider", slog.String("dns_provider", "ionos"))
+
 		var ionosConfig ionos.IONOSConfig
 		err := configClient.DNSProvider.ProviderConfig.Decode(&ionosConfig)
 		if err != nil {
+			logger.Error("Failed to create IONOS DNS provider",
+				slog.String("dns_provider", "ionos"),
+				slog.String("error", err.Error()),
+			)
 			panic(err)
 		}
+
 		dnsProvider, err = ionos.NewIonos(&ionosConfig)
 		if err != nil {
+			logger.Error("Failed to create IONOS DNS provider",
+				slog.String("dns_provider", "ionos"),
+				slog.String("error", err.Error()),
+			)
 			panic(err)
 		}
 	default:
+		logger.Error("Unknown DNS provider", slog.String("dns_provider", configClient.DNSProvider.Type))
 		panic(fmt.Errorf("unknown DNS provider: %s", configClient.DNSProvider.Type))
 	}
 
 	var notificationProvider notificationProvider.NotificationProvider
 	switch configClient.NotificationProvider.Type {
 	case "gotify":
+		logger.Info("Using Gotify notification provider", slog.String("notification_provider", "gotify"))
+
 		var gotifyConfig gotify.NotificationProviderImplGotifyConfig
 		err := configClient.NotificationProvider.ProviderConfig.Decode(&gotifyConfig)
 		if err != nil {
@@ -65,29 +104,39 @@ func main() {
 
 		notificationProvider, err = gotify.New(gotifyConfig)
 		if err != nil {
+			logger.Error("Failed to create Gotify notification provider",
+				slog.String("notification_provider", "gotify"),
+				slog.String("error", err.Error()),
+			)
 			panic(err)
 		}
 	default:
+		logger.Info("Using console notification provider", slog.String("notification_provider", "console"))
+
 		notificationProvider = notificationProviderConsole.New()
 	}
 
-	rdd := realDynDns.New(externalIpProvider, dnsProvider, notificationProvider, configClient.Domains)
+	rdd := realDynDns.New(externalIpProvider, dnsProvider, notificationProvider, configClient.Domains, logger.With(slog.String("service", "realDynDns")))
 
 	switch configClient.Mode {
 	case config.ScheduledMode:
+		logger.Info("Running in scheduled mode", slog.String("interval", configClient.CheckInterval))
+
 		schedule, job, err := rdd.RunWithSchedule(configClient.CheckInterval)
 		if err != nil {
+			logger.Error("Failed to create scheduler", slog.String("error", err.Error()))
 			panic(err)
 		}
 
-		fmt.Println("Starting scheduler")
+		logger.Info("Next run:", slog.String("time", job.NextRun().String()))
-		fmt.Println("Next run:", job.NextRun())
 		schedule.StartBlocking()
 	case config.RunOnceMode:
-		numberOfChanges, err := rdd.RunOnce()
+		logger.Info("Running in run once mode")
+
+		_, err := rdd.RunOnce()
 		if err != nil {
+			logger.Error("Failed to run once", slog.String("error", err.Error()))
 			panic(err)
 		}
-		fmt.Println("Number of changes:", numberOfChanges)
 	}
 }

pkg/config/config.go

@@ -3,7 +3,9 @@ package config
 import (
 	"errors"
 	"fmt"
+	"log/slog"
 	"os"
+	"strings"
 
 	"gopkg.in/yaml.v3"
 )
@@ -15,6 +17,7 @@ type Config struct {
 	NotificationProvider NotificationProviderConfig `yaml:"notification_provider,omitempty"`
 	Domains              []DomainConfig             `yaml:"domains"`
 	CheckInterval        string                     `yaml:"check_interval"`
+	LogLevel             string                     `yaml:"log_level"`
 }
 
 const (
@@ -22,6 +25,18 @@ const (
 	ScheduledMode = "Scheduled"
 )
 
+var LogLevelMap = map[string]slog.Level{
+	"debug": slog.LevelDebug,
+	"info":  slog.LevelInfo,
+	"warn":  slog.LevelWarn,
+	"error": slog.LevelError,
+}
+
+func isValidLogLevel(level string) bool {
+	_, ok := LogLevelMap[strings.ToLower(level)]
+	return ok
+}
+
 type DomainConfig struct {
 	TLD        string   `yaml:"tld"`
 	Subdomains []string `yaml:"subdomains"`
@@ -68,5 +83,9 @@ func (c *Config) validate() error {
 		return errors.New("check interval must be set when mode is 'Scheduled'")
 	}
 
+	if c.LogLevel != "" && !isValidLogLevel(c.LogLevel) {
+		return fmt.Errorf("log level must be one of 'debug', 'info', 'warn', 'error', but got %s", c.LogLevel)
+	}
+
 	return nil
 }

pkg/realDynDns/realDynDns.go

@@ -2,6 +2,7 @@ package realDynDns
 
 import (
 	"fmt"
+	"log/slog"
 	"time"
 
 	"realdnydns/pkg/config"
@@ -17,6 +18,7 @@ type ChangeDetector struct {
 	dnsProvider          dnsProvider.DNSProvider
 	notificationProvider notificationProvider.NotificationProvider
 	domains              []config.DomainConfig
+	logger               *slog.Logger
 }
 
 func New(
@@ -24,12 +26,14 @@ func New(
 	dnsProvider dnsProvider.DNSProvider,
 	notificationProvider notificationProvider.NotificationProvider,
 	domains []config.DomainConfig,
+	logger *slog.Logger,
 ) ChangeDetector {
 	return ChangeDetector{
 		externalIpProvider:   externalIpProvider,
 		dnsProvider:          dnsProvider,
 		notificationProvider: notificationProvider,
 		domains:              domains,
+		logger:               logger,
 	}
 }
 
@@ -58,8 +62,11 @@ func (c *ChangeDetector) RunOnce() (int, error) {
 }
 
 func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
+	c.logger.Info("Detecting and applying changes")
+
 	externalIp, err := c.externalIpProvider.GetExternalIp()
 	if err != nil {
+		c.logger.Error("Failed to retrieve external IP", slog.String("error", err.Error()))
 		return 0, err
 	}
 
@@ -67,28 +74,59 @@ func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
 
 	for _, domain := range c.domains {
 		for _, subdomain := range domain.Subdomains {
+			c.logger.Info("Checking record",
+				slog.String("tld", domain.TLD),
+				slog.String("subdomain", subdomain),
+			)
 			currentRecord, err := c.dnsProvider.GetRecord(domain.TLD, subdomain)
 			if err != nil {
+				c.logger.Error("Failed to retrieve record",
+					slog.String("error", err.Error()),
+					slog.String("tld", domain.TLD),
+					slog.String("subdomain", subdomain),
+				)
 				return numberUpdated, err
 			}
 
 			if currentRecord.IP != externalIp.String() {
+				c.logger.Info("Record has changed",
+					slog.String("tld", domain.TLD),
+					slog.String("subdomain", subdomain),
+					slog.String("current_ip", currentRecord.IP),
+					slog.String("external_ip", externalIp.String()),
+				)
+
 				err = c.notificationProvider.SendNotification(
 					fmt.Sprintf("Update %s.%s", subdomain, domain.TLD),
 					fmt.Sprintf("The IP of %s has changed from %s to %s", domain.TLD, currentRecord.IP, externalIp.String()),
 				)
 				if err != nil {
+					c.logger.Warn("Failed to send notification",
+						slog.String("error", err.Error()),
+					)
 					return numberUpdated, err
 				}
 
+				c.logger.Info("Updating record",
+					slog.String("tld", domain.TLD),
+					slog.String("subdomain", subdomain),
+					slog.String("current_ip", currentRecord.IP),
+					slog.String("external_ip", externalIp.String()),
+				)
 				_, err = c.dnsProvider.UpdateRecord(domain.TLD, subdomain, externalIp, currentRecord.TTL, currentRecord.Prio, currentRecord.Disabled)
-				numberUpdated++
 				if err != nil {
+					c.logger.Error("Failed to update record",
+						slog.String("error", err.Error()),
+						slog.String("tld", domain.TLD),
+						slog.String("subdomain", subdomain),
+					)
 					return numberUpdated, err
 				}
+				numberUpdated++
 			}
 		}
 	}
 
+	c.logger.Info("Run completed", slog.Int("number_of_changes", numberUpdated))
 	return numberUpdated, nil
 }

pkg/realDynDns/realDynDns_test.go

@@ -1,6 +1,7 @@
 package realDynDns
 
 import (
+	"log/slog"
 	"net"
 	"realdnydns/model/common"
 	"realdnydns/pkg/config"
@@ -72,7 +73,9 @@ func testDetectAndApplyChangesWithChanges() func(t *testing.T) {
 						"@",
 					},
 				},
-			})
+			},
+			slog.Default(),
+		)
 
 		numberUpdated, err := changeDetector.RunOnce()
 		if err != nil {
@@ -101,7 +104,9 @@ func testDetectAndApplyChangesWithoutChanges() func(t *testing.T) {
 						"@",
 					},
 				},
-			})
+			},
+			slog.Default(),
+		)
 
 		numberUpdated, err := changeDetector.RunOnce()
 		if err != nil {