done

internal/config.go

@@ -18,6 +18,7 @@ const (
 	envKeyOnChangeComment      = "ON_CHANGE_COMMENT"
 	envKeyCheckIntervalSeconds = "CHECK_INTERVAL_SECONDS"
 	envKeyNotifiers            = "NOTIFIERS"
+	envKeyIgnoredIpChange      = "IGNORED_IP_CHANGE"
 )
 
 type Config struct {
@@ -28,6 +29,7 @@ type Config struct {
 	OnChangeComment     string
 	Notifiers           []string
 	CheckInterval       time.Duration
+	IgnoredIpChange     []string
 }
 
 func (c Config) Validate() error {
@@ -61,5 +63,6 @@ func NewConfig() Config {
 		OnChangeComment:     os.Getenv(envKeyOnChangeComment),
 		Notifiers:           parseCommaDelimited(os.Getenv(envKeyNotifiers)),
 		CheckInterval:       time.Duration(checkInterval) * time.Second,
+		IgnoredIpChange:     parseCommaDelimited(os.Getenv(envKeyIgnoredIpChange)),
 	}
 }

internal/helpers.go

@@ -1,6 +1,8 @@
 package internal
 
-import "strings"
+import (
+	"strings"
+)
 
 func parseCommaDelimited(data string) []string {
 	out := make([]string, 0, strings.Count(data, ",")+1)

internal/ignore_list.go

@@ -0,0 +1,26 @@
+package internal
+
+import (
+	"net"
+	"regexp"
+)
+
+func checkAddress(address, pattern string) bool {
+	pattern = "^" + pattern + "$"
+	re := regexp.MustCompile(pattern)
+	return re.MatchString(address)
+}
+
+func IgnoredIpChange(ip net.IP, ignored []string) bool {
+	if len(ignored) == 0 {
+		return false
+	}
+
+	for _, i := range ignored {
+		if checkAddress(ip.String(), i) {
+			return true
+		}
+	}
+
+	return false
+}

internal/ignore_list_test.go

@@ -0,0 +1,75 @@
+package internal
+
+import "testing"
+
+func Test_checkAddress(t *testing.T) {
+	type args struct {
+		address string
+		pattern string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "empty",
+			args: args{
+				address: "192.168.0.1",
+				pattern: "",
+			},
+			want: false,
+		}, {
+			name: "true match 192.*",
+			args: args{
+				address: "192.168.0.1",
+				pattern: "192.*",
+			},
+			want: true,
+		}, {
+			name: "false match 193.*",
+			args: args{
+				address: "192.168.0.1",
+				pattern: "193.*",
+			},
+			want: false,
+		},
+		{
+			name: "true match 192.168.0.1",
+			args: args{
+				address: "192.168.0.1",
+				pattern: "192.168.0.1",
+			},
+			want: true,
+		},
+		{
+			name: "false not match 192.168.0.2",
+			args: args{
+				address: "192.168.0.1",
+				pattern: "192.168.0.2",
+			},
+			want: false,
+		}, {
+			name: "true match 192.168.0.*",
+			args: args{
+				address: "192.168.0.10",
+				pattern: "192.168.0.*",
+			},
+			want: true,
+		}, {
+			name: "false match 192.168.0.*",
+			args: args{
+				address: "192.168.1.10",
+				pattern: "192.168.0.*",
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := checkAddress(tt.args.address, tt.args.pattern); got != tt.want {
+				t.Errorf("checkAddress() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

main.go

@@ -64,6 +64,12 @@ func main() {
 		}
 		log.Printf("Current public ip `%s` (resolver: %s)", currentPublicIP, resolverTag)
 
+		// check if ip is not in ignore list
+		if internal.IgnoredIpChange(currentPublicIP, config.IgnoredIpChange) {
+			log.Printf("Ignored ip change `%s`, skipping.", currentPublicIP)
+			return
+		}
+
 		dns, err := allDNSRecords(ctx, api, cloudflare.ZoneIdentifier(zoneID))
 		if err != nil {
 			log.Fatal(err)