fix: nil pointer when sonyflake is not properly configured

Author: jsiebens

internal/server/server.go

@@ -17,6 +17,7 @@ import (
 	"github.com/jsiebens/ionscale/internal/service"
 	"github.com/jsiebens/ionscale/internal/stunserver"
 	"github.com/jsiebens/ionscale/internal/templates"
+	"github.com/jsiebens/ionscale/internal/util"
 	"github.com/labstack/echo-contrib/echoprometheus"
 	"github.com/labstack/echo-contrib/pprof"
 	"github.com/labstack/echo/v4"
@@ -53,6 +54,8 @@ func Start(ctx context.Context, c *config.Config) error {
 		return err
 	}
 
+	util.EnsureIDProvider()
+
 	derpMap, err := derp.LoadDERPSources(c)
 	if err != nil {
 		logger.Warn("not all derp sources are read successfully", zap.Error(err))

internal/util/id.go

@@ -1,8 +1,10 @@
 package util
 
 import (
+	"errors"
 	"fmt"
 	"github.com/sony/sonyflake"
+	"go.uber.org/zap"
 	"net"
 	"os"
 	"strconv"
@@ -11,28 +13,64 @@ import (
 )
 
 var (
-	sf     *sonyflake.Sonyflake
+	sf     provider
 	sfOnce sync.Once
 )
 
 func NextID() uint64 {
-	ensureProvider()
-	id, _ := sf.NextID()
+	EnsureIDProvider()
+	id, err := sf.NextID()
+	if err != nil {
+		panic(err)
+	}
 	return id
 }
 
-func ensureProvider() {
+type provider interface {
+	NextID() (uint64, error)
+}
+
+type errorProvider struct {
+	err error
+}
+
+func (e errorProvider) NextID() (uint64, error) {
+	return 0, fmt.Errorf("unable to generate ID, sonyflake not configured properly: %w", e.err)
+}
+
+func EnsureIDProvider() {
 	sfOnce.Do(func() {
-		sfInstance, err := sonyflake.New(sonyflake.Settings{
-			MachineID: machineID(),
-			StartTime: time.Date(2022, 05, 01, 00, 0, 0, 0, time.UTC),
+		sf = createIDProvider()
+	})
+}
+
+func createIDProvider() provider {
+	startTime := time.Date(2022, 05, 01, 00, 0, 0, 0, time.UTC)
+	
+	sfInstance, err := sonyflake.New(sonyflake.Settings{
+		MachineID: machineID(),
+		StartTime: startTime,
+	})
+
+	if err != nil && errors.Is(err, sonyflake.ErrNoPrivateAddress) {
+		id := RandUint16()
+		zap.L().Warn("failed to generate sonyflake machine id from private ip address, using a random machine id", zap.Uint16("id", id))
+
+		sfInstance, err = sonyflake.New(sonyflake.Settings{
+			MachineID: func() (uint16, error) { return id, nil },
+			StartTime: startTime,
 		})
+
 		if err != nil {
-			panic("unable to initialize sonyflake: " + err.Error())
+			return errorProvider{err}
 		}
+	}
 
-		sf = sfInstance
-	})
+	if err != nil {
+		return errorProvider{err}
+	}
+
+	return sfInstance
 }
 
 func machineID() func() (uint16, error) {

internal/util/util.go

@@ -4,6 +4,7 @@ import (
 	"crypto/md5"
 	"crypto/rand"
 	"crypto/rsa"
+	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
 	"math/big"
@@ -31,6 +32,15 @@ func RandUint64(n uint64) uint64 {
 	return val.Uint64()
 }
 
+func RandUint16() uint16 {
+	var randomBytes [2]byte
+	_, err := rand.Read(randomBytes[:])
+	if err != nil {
+		panic(err)
+	}
+	return binary.BigEndian.Uint16(randomBytes[:])
+}
+
 func RandomBytes(size int) ([]byte, error) {
 	buf := make([]byte, size)
 	if _, err := rand.Read(buf); err != nil {