Support for custom logger in servers

dhcpv4/server4/logger.go

@@ -0,0 +1,63 @@
+package server4
+
+import (
+	"github.com/insomniacslk/dhcp/dhcpv4"
+)
+
+// Logger is a handler which will be used to output logging messages
+type Logger interface {
+	// PrintMessage print _all_ DHCP messages
+	PrintMessage(prefix string, message *dhcpv4.DHCPv4)
+
+	// Printf is use to print the rest debugging information
+	Printf(format string, v ...interface{})
+}
+
+// EmptyLogger prints nothing
+type EmptyLogger struct{}
+
+// Printf is just a dummy function that does nothing
+func (e EmptyLogger) Printf(format string, v ...interface{}) {}
+
+// PrintMessage is just a dummy function that does nothing
+func (e EmptyLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {}
+
+// Printfer is used for actual output of the logger. For example *log.Logger is a Printfer.
+type Printfer interface {
+	// Printf is the function for logging output. Arguments are handled in the manner of fmt.Printf.
+	Printf(format string, v ...interface{})
+}
+
+// ShortSummaryLogger is a wrapper for Printfer to implement interface Logger.
+// DHCP messages are printed in the short format.
+type ShortSummaryLogger struct {
+	// Printfer is used for actual output of the logger
+	Printfer
+}
+
+// Printf prints a log message as-is via predefined Printfer
+func (s ShortSummaryLogger) Printf(format string, v ...interface{}) {
+	s.Printfer.Printf(format, v...)
+}
+
+// PrintMessage prints a DHCP message in the short format via predefined Printfer
+func (s ShortSummaryLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {
+	s.Printf("%s: %s", prefix, message)
+}
+
+// DebugLogger is a wrapper for Printfer to implement interface Logger.
+// DHCP messages are printed in the long format.
+type DebugLogger struct {
+	// Printfer is used for actual output of the logger
+	Printfer
+}
+
+// Printf prints a log message as-is via predefined Printfer
+func (d DebugLogger) Printf(format string, v ...interface{}) {
+	d.Printfer.Printf(format, v...)
+}
+
+// PrintMessage prints a DHCP message in the long format via predefined Printfer
+func (d DebugLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4) {
+	d.Printf("%s: %s", prefix, message.Summary())
+}

dhcpv4/server4/logger_test.go

@@ -0,0 +1,40 @@
+package server4
+
+import(
+	"log"
+	"os"
+	"testing"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEmptyLogger(t *testing.T) {
+	l := EmptyLogger{}
+	msg, err := dhcpv4.New()
+	require.Nil(t, err)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}
+
+func TestShortSummaryLogger(t *testing.T) {
+	l := ShortSummaryLogger{
+		Printfer: log.New(os.Stderr, "[dhcpv4] ", log.LstdFlags),
+	}
+	msg, err := dhcpv4.New()
+	require.Nil(t, err)
+	require.NotNil(t, msg)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}
+
+func TestDebugLogger(t *testing.T) {
+	l := DebugLogger{
+		Printfer: log.New(os.Stderr, "[dhcpv4] ", log.LstdFlags),
+	}
+	msg, err := dhcpv4.New()
+	require.Nil(t, err)
+	require.NotNil(t, msg)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}

dhcpv4/server4/server.go

@@ -3,6 +3,7 @@ package server4
 import (
 	"log"
 	"net"
+	"os"
 
 	"github.com/insomniacslk/dhcp/dhcpv4"
 )
@@ -68,32 +69,33 @@ type Handler func(conn net.PacketConn, peer net.Addr, m *dhcpv4.DHCPv4)
 type Server struct {
 	conn    net.PacketConn
 	Handler Handler
+	logger  Logger
 }
 
 // Serve serves requests.
 func (s *Server) Serve() error {
-	log.Printf("Server listening on %s", s.conn.LocalAddr())
-	log.Print("Ready to handle requests")
+	s.logger.Printf("Server listening on %s", s.conn.LocalAddr())
+	s.logger.Printf("Ready to handle requests")
 
 	defer s.Close()
 	for {
 		rbuf := make([]byte, 4096) // FIXME this is bad
 		n, peer, err := s.conn.ReadFrom(rbuf)
 		if err != nil {
-			log.Printf("Error reading from packet conn: %v", err)
+			s.logger.Printf("Error reading from packet conn: %v", err)
 			return err
 		}
-		log.Printf("Handling request from %v", peer)
+		s.logger.Printf("Handling request from %v", peer)
 
 		m, err := dhcpv4.FromBytes(rbuf[:n])
 		if err != nil {
-			log.Printf("Error parsing DHCPv4 request: %v", err)
+			s.logger.Printf("Error parsing DHCPv4 request: %v", err)
 			continue
 		}
 
 		upeer, ok := peer.(*net.UDPAddr)
 		if !ok {
-			log.Printf("Not a UDP connection? Peer is %s", peer)
+			s.logger.Printf("Not a UDP connection? Peer is %s", peer)
 			continue
 		}
 		// Set peer to broadcast if the client did not have an IP.
@@ -126,6 +128,7 @@ func WithConn(c net.PacketConn) ServerOpt {
 func NewServer(ifname string, addr *net.UDPAddr, handler Handler, opt ...ServerOpt) (*Server, error) {
 	s := &Server{
 		Handler: handler,
+		logger:  EmptyLogger{},
 	}
 
 	for _, o := range opt {
@@ -141,3 +144,28 @@ func NewServer(ifname string, addr *net.UDPAddr, handler Handler, opt ...ServerO
 	}
 	return s, nil
 }
+
+// WithSummaryLogger logs one-line DHCPv4 message summaries when sent & received.
+func WithSummaryLogger() ServerOpt {
+	return func(s *Server) {
+		s.logger = ShortSummaryLogger{
+			Printfer: log.New(os.Stderr, "[dhcpv4] ", log.LstdFlags),
+		}
+	}
+}
+
+// WithDebugLogger logs multi-line full DHCPv4 messages when sent & received.
+func WithDebugLogger() ServerOpt {
+	return func(s *Server) {
+		s.logger = DebugLogger{
+			Printfer: log.New(os.Stderr, "[dhcpv4] ", log.LstdFlags),
+		}
+	}
+}
+
+// WithLogger set the logger (see interface Logger).
+func WithLogger(newLogger Logger) ServerOpt {
+	return func(s *Server) {
+		s.logger = newLogger
+	}
+}

dhcpv6/server6/logger.go

@@ -0,0 +1,63 @@
+package server6
+
+import (
+	"github.com/insomniacslk/dhcp/dhcpv6"
+)
+
+// Logger is a handler which will be used to output logging messages
+type Logger interface {
+	// PrintMessage print _all_ DHCP messages
+	PrintMessage(prefix string, message *dhcpv6.Message)
+
+	// Printf is use to print the rest debugging information
+	Printf(format string, v ...interface{})
+}
+
+// EmptyLogger prints nothing
+type EmptyLogger struct{}
+
+// Printf is just a dummy function that does nothing
+func (e EmptyLogger) Printf(format string, v ...interface{}) {}
+
+// PrintMessage is just a dummy function that does nothing
+func (e EmptyLogger) PrintMessage(prefix string, message *dhcpv6.Message) {}
+
+// Printfer is used for actual output of the logger. For example *log.Logger is a Printfer.
+type Printfer interface {
+	// Printf is the function for logging output. Arguments are handled in the manner of fmt.Printf.
+	Printf(format string, v ...interface{})
+}
+
+// ShortSummaryLogger is a wrapper for Printfer to implement interface Logger.
+// DHCP messages are printed in the short format.
+type ShortSummaryLogger struct {
+	// Printfer is used for actual output of the logger
+	Printfer
+}
+
+// Printf prints a log message as-is via predefined Printfer
+func (s ShortSummaryLogger) Printf(format string, v ...interface{}) {
+	s.Printfer.Printf(format, v...)
+}
+
+// PrintMessage prints a DHCP message in the short format via predefined Printfer
+func (s ShortSummaryLogger) PrintMessage(prefix string, message *dhcpv6.Message) {
+	s.Printf("%s: %s", prefix, message)
+}
+
+// DebugLogger is a wrapper for Printfer to implement interface Logger.
+// DHCP messages are printed in the long format.
+type DebugLogger struct {
+	// Printfer is used for actual output of the logger
+	Printfer
+}
+
+// Printf prints a log message as-is via predefined Printfer
+func (d DebugLogger) Printf(format string, v ...interface{}) {
+	d.Printfer.Printf(format, v...)
+}
+
+// PrintMessage prints a DHCP message in the long format via predefined Printfer
+func (d DebugLogger) PrintMessage(prefix string, message *dhcpv6.Message) {
+	d.Printf("%s: %s", prefix, message.Summary())
+}

dhcpv6/server6/logger_test.go

@@ -0,0 +1,40 @@
+package server6
+
+import(
+	"log"
+	"os"
+	"testing"
+
+	"github.com/insomniacslk/dhcp/dhcpv6"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEmptyLogger(t *testing.T) {
+	l := EmptyLogger{}
+	msg, err := dhcpv6.NewMessage()
+	require.Nil(t, err)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}
+
+func TestShortSummaryLogger(t *testing.T) {
+	l := ShortSummaryLogger{
+		Printfer: log.New(os.Stderr, "[dhcpv6] ", log.LstdFlags),
+	}
+	msg, err := dhcpv6.NewMessage()
+	require.Nil(t, err)
+	require.NotNil(t, msg)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}
+
+func TestDebugLogger(t *testing.T) {
+	l := DebugLogger{
+		Printfer: log.New(os.Stderr, "[dhcpv6] ", log.LstdFlags),
+	}
+	msg, err := dhcpv6.NewMessage()
+	require.Nil(t, err)
+	require.NotNil(t, msg)
+	l.Printf("test")
+	l.PrintMessage("prefix", msg)
+}

dhcpv6/server6/server.go

@@ -56,6 +56,7 @@ func main() {
 import (
 	"log"
 	"net"
+	"os"
 
 	"github.com/insomniacslk/dhcp/dhcpv6"
 	"golang.org/x/net/ipv6"
@@ -69,27 +70,28 @@ type Handler func(conn net.PacketConn, peer net.Addr, m dhcpv6.DHCPv6)
 type Server struct {
 	conn    net.PacketConn
 	handler Handler
+	logger  Logger
 }
 
 // Serve starts the DHCPv6 server. The listener will run in background, and can
 // be interrupted with `Server.Close`.
 func (s *Server) Serve() error {
-	log.Printf("Server listening on %s", s.conn.LocalAddr())
-	log.Print("Ready to handle requests")
+	s.logger.Printf("Server listening on %s", s.conn.LocalAddr())
+	s.logger.Printf("Ready to handle requests")
 
 	defer s.Close()
 	for {
 		rbuf := make([]byte, 4096) // FIXME this is bad
 		n, peer, err := s.conn.ReadFrom(rbuf)
 		if err != nil {
-			log.Printf("Error reading from packet conn: %v", err)
+			s.logger.Printf("Error reading from packet conn: %v", err)
 			return err
 		}
-		log.Printf("Handling request from %v", peer)
+		s.logger.Printf("Handling request from %v", peer)
 
 		d, err := dhcpv6.FromBytes(rbuf[:n])
 		if err != nil {
-			log.Printf("Error parsing DHCPv6 request: %v", err)
+			s.logger.Printf("Error parsing DHCPv6 request: %v", err)
 			continue
 		}
 
@@ -125,6 +127,7 @@ func WithConn(conn net.PacketConn) ServerOpt {
 func NewServer(ifname string, addr *net.UDPAddr, handler Handler, opt ...ServerOpt) (*Server, error) {
 	s := &Server{
 		handler: handler,
+		logger:  EmptyLogger{},
 	}
 
 	for _, o := range opt {
@@ -181,3 +184,28 @@ func NewServer(ifname string, addr *net.UDPAddr, handler Handler, opt ...ServerO
 
 	return s, nil
 }
+
+// WithSummaryLogger logs one-line DHCPv6 message summaries when sent & received.
+func WithSummaryLogger() ServerOpt {
+	return func(s *Server) {
+		s.logger = ShortSummaryLogger{
+			Printfer: log.New(os.Stderr, "[dhcpv6] ", log.LstdFlags),
+		}
+	}
+}
+
+// WithDebugLogger logs multi-line full DHCPv6 messages when sent & received.
+func WithDebugLogger() ServerOpt {
+	return func(s *Server) {
+		s.logger = DebugLogger{
+			Printfer: log.New(os.Stderr, "[dhcpv6] ", log.LstdFlags),
+		}
+	}
+}
+
+// WithLogger set the logger (see interface Logger).
+func WithLogger(newLogger Logger) ServerOpt {
+	return func(s *Server) {
+		s.logger = newLogger
+	}
+}