rewrite in go and add support for ipv6

env.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func GetAPIKey() string {
+	value, isSet := os.LookupEnv("API_KEY")
+	if !isSet {
+		log.Panic("Missing environment variable 'API_KEY'")
+	}
+
+	return value
+}
+
+func GetZoneID() string {
+	value, isSet := os.LookupEnv("ZONE_ID")
+	if !isSet {
+		log.Panic("Missing environment variable 'ZONE_ID'")
+	}
+
+	return value
+}
+
+func GetDomainNames() []string {
+	value, isSet := os.LookupEnv("DOMAIN_NAMES")
+	if !isSet {
+		log.Panic("Missing environment variable 'DOMAIN_NAMES'")
+	}
+
+	return strings.Split(value, ",")
+}
+
+func UseIPv4() bool {
+	value, isSet := os.LookupEnv("RECORD_TYPES")
+	if !isSet {
+		return true
+	}
+
+	switch value {
+	case "A", "*":
+		return true
+	case "AAAA":
+		return false
+	default:
+		log.Panicf("Unrecognized value '%v' for 'RECORD_TYPES'", value)
+		return false
+	}
+}
+
+func UseIPv6() bool {
+	value, isSet := os.LookupEnv("RECORD_TYPES")
+	if !isSet {
+		return false
+	}
+
+	switch value {
+	case "AAAA", "*":
+		return true
+	case "A":
+		return false
+	default:
+		log.Panicf("Unrecognized value '%v' for 'RECORD_TYPES'", value)
+		return false
+	}
+}
+
+func GetInterval() int {
+	value, isSet := os.LookupEnv("INTERVAL")
+
+	if !isSet {
+		return 5
+	}
+
+	interval, err := strconv.Atoi(value)
+	if err != nil {
+		log.Panic("Error converting 'INTERVAL' to integer: ", err)
+	}
+
+	return interval
+}