fix: determinate ipv6 availability before make ipv6 request (#5)

go.mod

@@ -7,4 +7,5 @@ require (
 	github.com/ovh/go-ovh v1.1.0
 	github.com/rs/zerolog v1.26.1
 	github.com/spf13/viper v1.10.1
+	github.com/stretchr/testify v1.8.1 // indirect
 )

go.sum

@@ -336,13 +336,19 @@ github.com/spf13/viper v1.10.1 h1:nuJZuYpG7gTj/XqiUwg8bA0cp1+M2mC3J4g5luUYBKk=
 github.com/spf13/viper v1.10.1/go.mod h1:IGlFPqhNAPKRxohIzWpI5QEy4kuI7tcl5WvR+8qy1rU=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/subosito/gotenv v1.2.0 h1:Slr1R9HxAlEKefgq5jn9U+DnETlIUa6HfgEzj0g5d7s=
 github.com/subosito/gotenv v1.2.0/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69rRypqCw=
 github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926/go.mod h1:9ESjWnEqriFuLhtthL60Sar/7RFoluCcXsuvEwTV5KM=
@@ -784,6 +790,8 @@ gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

internal/pkg/ip/ip.go

@@ -1,10 +1,12 @@
 package ip
 
 import (
+	"context"
 	"io/ioutil"
 	"net"
 	"net/http"
 	"strings"
+	"time"
 
 	"github.com/rs/zerolog/log"
 )
@@ -20,34 +22,71 @@ var (
  * Fetch the IPv4 of current machine with https://ipconfig.co service
  * Thanks to him
  */
-func fetchIPv4() net.IP {
-	return fetch("https://v4.ifconfig.co/ip")
+func fetchIPv4() *net.IP {
+	return fetch("https://ifconfig.co/ip", "tcp4")
 }
 
 /**
  * Fetch the IPv6 of current machine with https://ipconfig.co service
  * Thanks to him
  */
-func fetchIPv6() net.IP {
-	return fetch("https://v6.ifconfig.co/ip")
+func fetchIPv6() *net.IP {
+	return fetch("https://ifconfig.co/ip", "tcp6")
 }
 
 /**
  * Fetch ip of current machine with given url
  * url needs to return ip on text/plain Content-Type
  */
-func fetch(url string) net.IP {
+func fetch(url string, mode string) *net.IP {
 	log.Debug().Msg("Getting current IP")
-	resp, err := http.Get(url)
+	httpClient := &http.Client{
+		Timeout: 10 * time.Second,
+	}
+
+	if mode == "tcp6" && !ipv6Available() {
+		log.Debug().Msg("No IPv6 available")
+		return nil
+	}
+
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+		return (&net.Dialer{}).DialContext(ctx, mode, addr)
+	}
+	httpClient.Transport = transport
+
+	resp, err := httpClient.Get(url)
 	if err != nil {
 		log.Error().Err(err).Msg("cannot fetch current IP")
+		return nil
 	}
 
 	bodyBytes, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		log.Error().Err(err).Msg("cannot fetch current IP")
+		return nil
 	}
 
 	s := strings.Trim(string(bodyBytes), " \n")
-	return net.ParseIP(s)
+	ip := net.ParseIP(s)
+
+	log.Debug().Msgf("Current IP %s: %s", mode, ip.String())
+	return &ip
+}
+
+func ipv6Available() bool {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return false
+	}
+
+	for _, addr := range addrs {
+		if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
+			if ipnet.IP.To4() == nil {
+				return true
+			}
+		}
+	}
+
+	return false
 }

internal/pkg/ip/ip_test.go

@@ -0,0 +1,24 @@
+package ip
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFetchIpv4(t *testing.T) {
+	ip := fetchIPv4()
+
+	assert.NotNil(t, ip)
+}
+
+func TestFetchIpv6(t *testing.T) {
+	ip := fetchIPv6()
+
+	if ip == nil {
+		t.Skip("No IPv6")
+	}
+
+	assert.NotNil(t, ip)
+	assert.True(t, ip.To4() == nil)
+}

internal/pkg/ip/state.go

@@ -19,16 +19,18 @@ func FetchIPChangeRoutine(c chan IPChangeState, interval time.Duration) {
 
 		var oldIpv4 = CurrentIPv4
 		var fetchedIPv4 = fetchIPv4()
-		if !oldIpv4.Equal(fetchedIPv4) {
-			CurrentIPv4 = fetchedIPv4
+		if fetchedIPv4 != nil && !oldIpv4.Equal(*fetchedIPv4) {
+			CurrentIPv4 = *fetchedIPv4
 			state.IPV4Change = true
 		}
 
-		var oldIpv6 = CurrentIPv6
-		var fetchedIPv6 = fetchIPv6()
-		if !oldIpv6.Equal(fetchedIPv6) {
-			CurrentIPv6 = fetchedIPv6
-			state.IPV6Change = true
+		if ipv6Available() {
+			var oldIpv6 = CurrentIPv6
+			var fetchedIPv6 = fetchIPv6()
+			if fetchedIPv6 != nil && !oldIpv6.Equal(*fetchedIPv6) {
+				CurrentIPv6 = *fetchedIPv6
+				state.IPV6Change = true
+			}
 		}
 
 		c <- state