Updating dnsimple with ip from internet service

• Get dnsimple oauth token from flag or environment variable
 • Check for ip address from whatismyipv6.buddy.wtf
 • Check what the dns record for the current host is set to
 • After getting record and ip address, either create, updated, or do
   nothing for the given host

TODO: clean up code

main.go

@@ -5,7 +5,11 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"strconv"
+	"strings"
+	"sync"
 
+	"github.com/dnsimple/dnsimple-go/dnsimple"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli"
 )
@@ -22,17 +26,97 @@ func main() {
 			Value: "https://whatismyipv6.buddy.wtf/json",
 			Usage: "url to use to get public ip address",
 		},
+
+		cli.StringFlag{
+			EnvVar: "DNSIMPLE_TOKEN",
+			Name:   "dnsimple-token",
+			Usage:  "dnsimple token",
+		},
 	}
 
 	app.Run(os.Args)
 }
 
+type runtimeError string
+
+func (e runtimeError) Error() string {
+	return string(e)
+}
+
 func action(context *cli.Context) error {
+	var wg sync.WaitGroup
+	if context.NArg() < 1 {
+		return runtimeError("requires host argument")
+	}
+
+	host := context.Args().Get(0)
+
+	wg.Add(1)
+	var getIPError error
+	var ip string
+	go func() {
+		defer wg.Done()
 		result, err := getIP(context.String("url"))
 		if err != nil {
-		return errors.Wrap(err, "could not get IP address")
+			getIPError = errors.Wrap(err, "could not get IP address")
+			return
+		}
+		ip = result.IP
+	}()
+
+	var dnSimpleAccountID string
+	var getRecordError error
+	var record *dnsimple.ZoneRecord
+	credentials := dnsimple.NewOauthTokenCredentials(context.String("dnsimple-token"))
+	dnSimpleClient := dnsimple.NewClient(credentials)
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		accountID, result, err := getRecord(dnSimpleClient, host, "AAAA")
+		dnSimpleAccountID = accountID
+		if err != nil {
+			getRecordError = errors.Wrap(err, "could not get ip for host")
+			return
+		}
+		record = result
+	}()
+
+	wg.Wait()
+
+	if getIPError != nil {
+		return errors.Wrap(getIPError, "could no get ip address")
+	}
+	if getRecordError != nil {
+		switch errors.Cause(getRecordError).(type) {
+		case notFoundError:
+			break
+		default:
+			return errors.Wrap(getRecordError, "could no get record")
+		}
+	}
+
+	subdomain, domain, _ := splitHost(host)
+	if record == nil {
+		_, err := dnSimpleClient.Zones.CreateRecord(dnSimpleAccountID, domain, dnsimple.ZoneRecord{
+			Name:    subdomain,
+			Type:    "AAAA",
+			Content: ip,
+		})
+		if err != nil {
+			return errors.Wrap(err, "could not create record")
+		}
+		fmt.Printf("%s record created for %s as %s\n", "AAAA", host, ip)
+	} else if ip != record.Content {
+		record.Content = ip
+		_, err := dnSimpleClient.Zones.UpdateRecord(dnSimpleAccountID, domain, record.ID, *record)
+		if err != nil {
+			return errors.Wrap(err, "could not update record")
+		}
+		fmt.Printf("%s record for %s updated to %s\n", "AAAA", host, ip)
+	} else {
+		fmt.Printf("%s record for %s already set as %s\n", "AAAA", host, ip)
 	}
-	fmt.Println(result.IP)
 	return nil
 }
 
@@ -41,6 +125,57 @@ type whatIsMyIPResult struct {
 	Version string `json:version`
 }
 
+type notFoundError error
+
+func getRecord(client *dnsimple.Client, host string, kind string) (string, *dnsimple.ZoneRecord, error) {
+	subdomain, domain, err := splitHost(host)
+	if err != nil {
+		return "", nil, errors.Wrap(err, "unable to parse host")
+	}
+	accountID, err := getAccountID(client)
+	if err != nil {
+		return "", nil, errors.Wrap(err, "could not get account id")
+	}
+
+	records, err := client.Zones.ListRecords(accountID, domain, &dnsimple.ZoneRecordListOptions{})
+	if err != nil {
+		return "", nil, errors.Wrap(err, "could not get list of records")
+	}
+
+	for _, record := range records.Data {
+		if record.ZoneID == domain && record.Name == subdomain && record.Type == kind {
+			return accountID, &record, nil
+		}
+	}
+
+	return accountID, nil, notFoundError(errors.New("could not find record"))
+}
+
+func getAccountID(client *dnsimple.Client) (string, error) {
+	whoamiResponse, err := client.Identity.Whoami()
+	if err != nil {
+		return "", errors.Wrap(err, "could not get account information from dnsimple")
+	}
+	if whoamiResponse.Data.Account == nil {
+		return "", errors.New("could not get account information")
+	}
+	return strconv.Itoa(whoamiResponse.Data.Account.ID), nil
+}
+
+func splitHost(host string) (subdomain string, domain string, err error) {
+	subdomains := strings.Split(host, ".")
+
+	if len(subdomains) >= 3 {
+		domain = strings.Join(subdomains[len(subdomains)-2:], ".")
+		subdomain = strings.Join(subdomains[:len(subdomains)-2], ".")
+	} else if len(subdomains) == 2 {
+		domain = strings.Join(subdomains, ".")
+	} else {
+		err = errors.New("invalid domain")
+	}
+	return subdomain, domain, err
+}
+
 func getIP(url string) (*whatIsMyIPResult, error) {
 	result, err := http.Get(url)
 	if err != nil {