refactor: update dependencies and enhance logging with slog

.devcontainer/devcontainer.json

@@ -0,0 +1,32 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/go
+{
+  "name": "Go",
+  // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+  "image": "mcr.microsoft.com/devcontainers/go:1-1.23-bookworm",
+
+  // Features to add to the dev container. More info: https://containers.dev/features.
+  // "features": {},
+
+  // Configure tool-specific properties.
+  "customizations": {
+    // Configure properties specific to VS Code.
+    "vscode": {
+      "settings": {},
+      "extensions": ["streetsidesoftware.code-spell-checker"]
+    }
+  },
+
+  // Use 'forwardPorts' to make a list of ports inside the container available locally.
+  // "forwardPorts": [9000],
+
+  // Use 'portsAttributes' to set default properties for specific forwarded ports.
+  // More info: https://containers.dev/implementors/json_reference/#port-attributes
+  "portsAttributes": {},
+
+  // Use 'postCreateCommand' to run commands after the container is created.
+  "postCreateCommand": "go mod download"
+
+  // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+  // "remoteUser": "root"
+}

avahi/publisher.go

@@ -2,6 +2,7 @@ package avahi
 
 import (
 	"fmt"
+	"log/slog"
 
 	"github.com/godbus/dbus/v5"
 	"github.com/holoplot/go-avahi"
@@ -25,24 +26,27 @@ type Publisher struct {
 
 // NewPublisher creates a new service for Publisher.
 func NewPublisher() (*Publisher, error) {
+	slog.Debug("creating new publisher")
+
 	conn, err := dbus.SystemBus()
 	if err != nil {
-		return nil, fmt.Errorf("failed to connect to system bus: %v", err)
+		return nil, fmt.Errorf("failed to connect to system bus: %w", err)
 	}
 
 	server, err := avahi.ServerNew(conn)
 	if err != nil {
-		return nil, fmt.Errorf("failed to create Avahi server: %v", err)
+		return nil, fmt.Errorf("failed to create Avahi server: %w", err)
 	}
 
 	avahiFqdn, err := server.GetHostNameFqdn()
 	if err != nil {
-		return nil, fmt.Errorf("failed to get FQDN from Avahi: %v", err)
+		return nil, fmt.Errorf("failed to get FQDN from Avahi: %w", err)
 	}
+	slog.Debug("got FQDN from Avahi", "fqdn", avahiFqdn)
 
 	group, err := server.EntryGroupNew()
 	if err != nil {
-		return nil, fmt.Errorf("failed to create entry group: %v", err)
+		return nil, fmt.Errorf("failed to create entry group: %w", err)
 	}
 
 	fqdn := dns.Fqdn(avahiFqdn)
@@ -52,9 +56,10 @@ func NewPublisher() (*Publisher, error) {
 	rdataField := make([]byte, len(fqdn)+1)
 	_, err = dns.PackDomainName(fqdn, rdataField, 0, nil, false)
 	if err != nil {
-		return nil, fmt.Errorf("failed to pack FQDN into RDATA: %v", err)
+		return nil, fmt.Errorf("failed to pack FQDN into RDATA: %w", err)
 	}
 
+	slog.Debug("publisher created successfully", "fqdn", fqdn)
 	return &Publisher{
 		dbusConn:        conn,
 		avahiServer:     server,
@@ -71,13 +76,16 @@ func (p *Publisher) Fqdn() string {
 
 // PublishCNAMES send via Avahi-daemon CNAME records with the provided TTL.
 func (p *Publisher) PublishCNAMES(cnames []string, ttl uint32) error {
+	slog.Debug("publishing CNAMEs", "count", len(cnames), "ttl", ttl)
+
 	// Reset the entry group to remove all records.
 	// Because we can't update records without it after the `Commit`.
 	if err := p.avahiEntryGroup.Reset(); err != nil {
-		return fmt.Errorf("failed to reset entry group: %v", err)
+		return fmt.Errorf("failed to reset entry group: %w", err)
 	}
 
 	for _, cname := range cnames {
+		slog.Debug("adding CNAME record", "cname", cname)
 		err := p.avahiEntryGroup.AddRecord(
 			avahi.InterfaceUnspec,
 			avahi.ProtoUnspec,
@@ -89,18 +97,20 @@ func (p *Publisher) PublishCNAMES(cnames []string, ttl uint32) error {
 			p.rdataField,
 		)
 		if err != nil {
-			return fmt.Errorf("failed to add record to entry group: %v", err)
+			return fmt.Errorf("failed to add record to entry group: %w", err)
 		}
 	}
 
 	if err := p.avahiEntryGroup.Commit(); err != nil {
-		return fmt.Errorf("failed to commit entry group: %v", err)
+		return fmt.Errorf("failed to commit entry group: %w", err)
 	}
 
+	slog.Debug("successfully published CNAMEs")
 	return nil
 }
 
 // Close associated resources.
 func (p *Publisher) Close() {
+	slog.Debug("closing publisher")
 	p.avahiServer.Close() // It also closes the DBus connection and free the entry group
 }

cmd/cname.go

@@ -3,7 +3,7 @@ package cmd
 import (
 	"context"
 	"fmt"
-	"log"
+	"log/slog"
 	"time"
 
 	"github.com/miekg/dns"
@@ -14,16 +14,16 @@ import (
 
 // formatCname formats CNAMEs by ensuring they are fully qualified domain names (FQDNs).
 func formatCname(hostnameFqdn string, cnames []string) []string {
-	log.Println("Formatting CNAMEs:")
+	slog.Info("formatting CNAMEs")
 
 	formattedCnames := make([]string, len(cnames))
 	for i, cname := range cnames {
 		if !dns.IsFqdn(cname) {
 			formattedCnames[i] = dns.Fqdn(cname + "." + hostnameFqdn)
-			log.Printf("  > '%s' (added FQDN)", formattedCnames[i])
+			slog.Info("formatted CNAME", "cname", formattedCnames[i], "note", "added FQDN")
 		} else {
 			formattedCnames[i] = cname
-			log.Printf("  > '%s'", cname)
+			slog.Info("formatted CNAME", "cname", cname)
 		}
 	}
 
@@ -32,7 +32,7 @@ func formatCname(hostnameFqdn string, cnames []string) []string {
 
 // publishLoop handles the continuous publishing of CNAME records.
 func publishing(ctx context.Context, publisher *avahi.Publisher, cnames []string, ttl, interval uint32) error {
-	log.Printf("Publishing every %ds and CNAME TTL %ds", interval, ttl)
+	slog.Info("publishing CNAMEs", "interval", interval, "ttl", ttl)
 
 	resendDuration := time.Duration(interval) * time.Second
 	ticker := time.NewTicker(resendDuration)
@@ -52,7 +52,7 @@ func publishing(ctx context.Context, publisher *avahi.Publisher, cnames []string
 			}
 		case <-ctx.Done():
 			fmt.Println() // Add new line after ^C
-			log.Println("Closing publisher")
+			slog.Info("closing publisher")
 			publisher.Close()
 			return nil
 		}
@@ -61,7 +61,7 @@ func publishing(ctx context.Context, publisher *avahi.Publisher, cnames []string
 
 // runCname sets up and starts the CNAME publishing process.
 func runCname(ctx context.Context, publisher *avahi.Publisher, cnames []string, fqdn string, ttl, interval uint32) error {
-	log.Printf("FQDN: %s", fqdn)
+	slog.Info("running CNAME publisher", "fqdn", fqdn)
 
 	formattedCname := formatCname(fqdn, cnames)
 	return publishing(ctx, publisher, formattedCname, ttl, interval)
@@ -101,14 +101,14 @@ func Cname(ctx context.Context) *cli.Command {
 				return fmt.Errorf("at least one CNAME should be provided")
 			}
 
-			log.Println("Creating publisher")
+			slog.Info("creating publisher")
 			publisher, err := avahi.NewPublisher()
 			if err != nil {
 				return fmt.Errorf("failed to create publisher: %w", err)
 			}
 
 			if fqdn == "" {
-				log.Println("Getting FQDN from Avahi")
+				slog.Info("getting FQDN from Avahi")
 				fqdn = publisher.Fqdn()
 			}
 

cmd/subdomain.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"log"
+	"log/slog"
 	"net"
 	"strings"
 
@@ -21,6 +21,7 @@ type dnsMsg struct {
 
 // listen creates a UDP connection to multicast for listening to DNS messages.
 func listen() (*net.UDPConn, error) {
+	slog.Debug("creating multicast UDP connection", "ip", "224.0.0.251", "port", 5353)
 	addr := &net.UDPAddr{
 		IP:   net.ParseIP("224.0.0.251"),
 		Port: 5353,
@@ -31,11 +32,13 @@ func listen() (*net.UDPConn, error) {
 		return nil, err
 	}
 
+	slog.Debug("multicast UDP connection created successfully")
 	return conn, nil
 }
 
 // reader reads DNS messages from the UDP connection. Assume that context is canceled before closing the connection.
 func reader(ctx context.Context, conn *net.UDPConn) chan *dnsMsg {
+	slog.Debug("starting DNS message reader")
 	buf := make([]byte, 1500)
 
 	msgCh := make(chan *dnsMsg)
@@ -49,7 +52,7 @@ func reader(ctx context.Context, conn *net.UDPConn) chan *dnsMsg {
 			bytesRead, remoteAddress, err := conn.ReadFromUDP(buf)
 			if err != nil {
 				if ctx.Err() != nil {
-					log.Println("Closing reader")
+					slog.Info("closing reader")
 					close(msgCh)
 					return
 				}
@@ -58,12 +61,14 @@ func reader(ctx context.Context, conn *net.UDPConn) chan *dnsMsg {
 				msgCh <- dnsMsg
 				return
 			}
+			slog.Debug("received UDP message", "bytes", bytesRead, "from", remoteAddress)
 
 			if err := dnsMsg.msg.Unpack(buf[:bytesRead]); err != nil {
 				dnsMsg.err = errors.Join(dnsMsg.err, fmt.Errorf("failed to unpack message: %w", err))
 				msgCh <- dnsMsg
 				continue
 			}
+			slog.Debug("unpacked DNS message successfully")
 
 			msgCh <- dnsMsg
 		}
@@ -75,20 +80,24 @@ func reader(ctx context.Context, conn *net.UDPConn) chan *dnsMsg {
 // selectQuestion filters and selects questions with the given FQDN suffix.
 func selectQuestion(fqdn string, qs []dns.Question) (res []string) {
 	suffix := "." + fqdn
+	slog.Debug("filtering DNS questions", "suffix", suffix, "questions", len(qs))
+
 	for _, q := range qs {
 		if strings.HasSuffix(q.Name, suffix) {
+			slog.Debug("found matching question", "name", q.Name, "type", dns.TypeToString[q.Qtype])
 			res = append(res, q.Name)
 		}
 	}
 
+	slog.Debug("filtered questions", "matches", len(res))
 	return res
 }
 
 // runSubdomain starts listening for DNS messages, filters relevant questions, and publishes corresponding CNAMEs.
 func runSubdomain(ctx context.Context, publisher *avahi.Publisher, fqdn string, ttl uint32) error {
-	log.Printf("FQDN: %s", fqdn)
+	slog.Info("running subdomain publisher", "fqdn", fqdn)
 
-	log.Println("Create connection to multicast")
+	slog.Info("creating connection to multicast")
 	conn, err := listen()
 	if err != nil {
 		return fmt.Errorf("failed to create connection: %w", err)
@@ -99,23 +108,25 @@ func runSubdomain(ctx context.Context, publisher *avahi.Publisher, fqdn string,
 	go func() {
 		<-ctx.Done()
 		fmt.Println() // Add new line after ^C
-		log.Println("Closing connection")
+		slog.Info("closing connection")
 		if err := conn.Close(); err != nil {
-			log.Printf("Failed to close connection: %v", err)
+			slog.Error("failed to close connection", "error", err)
 		}
 	}()
 
-	log.Println("Start listening")
+	slog.Info("start listening")
 	for m := range msgCh {
 		msg := m.msg
 		if m.err != nil {
-			log.Printf("Error: %v", m.err)
+			slog.Error("error processing message", "error", m.err)
 			continue
 		}
+		slog.Debug("processing DNS message", "questions", len(msg.Question))
 
 		found := selectQuestion(fqdn, msg.Question)
 
 		if len(found) > 0 {
+			slog.Debug("publishing matching CNAMEs", "count", len(found))
 			if err := publisher.PublishCNAMES(found, ttl); err != nil {
 				return fmt.Errorf("failed to publish CNAMEs: %w", err)
 			}
@@ -147,15 +158,15 @@ func Subdomain(ctx context.Context) *cli.Command {
 			ttl := uint32(cCtx.Uint("ttl"))
 			fqdn := cCtx.String("fqdn")
 
-			log.Println("Creating publisher")
+			slog.Info("creating publisher")
 			publisher, err := avahi.NewPublisher()
 			if err != nil {
 				return fmt.Errorf("failed to create publisher: %w", err)
 			}
 			defer publisher.Close()
 
 			if fqdn == "" {
-				log.Println("Getting FQDN from Avahi")
+				slog.Info("getting FQDN from Avahi")
 				fqdn = publisher.Fqdn()
 			}
 

go.mod

@@ -3,9 +3,11 @@ module github.com/grishy/go-avahi-cname
 go 1.23.3
 
 require (
-	github.com/carlmjohnson/versioninfo v0.22.5
+	github.com/earthboundkid/versioninfo/v2 v2.24.1
 	github.com/godbus/dbus/v5 v5.1.0
 	github.com/holoplot/go-avahi v1.0.1
+	github.com/lmittmann/tint v1.0.6
+	github.com/mattn/go-isatty v0.0.20
 	github.com/miekg/dns v1.1.62
 	github.com/urfave/cli/v2 v2.27.5
 )

go.sum

@@ -1,12 +1,16 @@
-github.com/carlmjohnson/versioninfo v0.22.5 h1:O00sjOLUAFxYQjlN/bzYTuZiS0y6fWDQjMRvwtKgwwc=
-github.com/carlmjohnson/versioninfo v0.22.5/go.mod h1:QT9mph3wcVfISUKd0i9sZfVrPviHuSF+cUtLjm2WSf8=
 github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
 github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/earthboundkid/versioninfo/v2 v2.24.1 h1:SJTMHaoUx3GzjjnUO1QzP3ZXK6Ee/nbWyCm58eY3oUg=
+github.com/earthboundkid/versioninfo/v2 v2.24.1/go.mod h1:VcWEooDEuyUJnMfbdTh0uFN4cfEIg+kHMuWB2CDCLjw=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/godbus/dbus/v5 v5.1.0 h1:4KLkAxT3aOY8Li4FRJe/KvhoNFFxo0m6fNuFUO8QJUk=
 github.com/godbus/dbus/v5 v5.1.0/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/holoplot/go-avahi v1.0.1 h1:XcqR2keL4qWRnlxHD5CAOdWpLFZJ+EOUK0vEuylfvvk=
 github.com/holoplot/go-avahi v1.0.1/go.mod h1:qH5psEKb0DK+BRplMfc+RY4VMOlbf6mqfxgpMy6aP0M=
+github.com/lmittmann/tint v1.0.6 h1:vkkuDAZXc0EFGNzYjWcV0h7eEX+uujH48f/ifSkJWgc=
+github.com/lmittmann/tint v1.0.6/go.mod h1:HIS3gSy7qNwGCj+5oRjAutErFBl4BzdQP6cJZ0NfMwE=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/miekg/dns v1.1.62 h1:cN8OuEF1/x5Rq6Np+h1epln8OiyPWV+lROx9LxcGgIQ=
 github.com/miekg/dns v1.1.62/go.mod h1:mvDlcItzm+br7MToIKqkglaGhlFMHJ9DTNNWONWXbNQ=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
@@ -21,6 +25,7 @@ golang.org/x/net v0.27.0 h1:5K3Njcw06/l2y9vpGCSdcxWOYHOUk3dVNGDXN+FvAys=
 golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE=
 golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/tools v0.22.0 h1:gqSGLZqv+AI9lIQzniJ0nZDRG5GBPsSi+DRNHWNz6yA=