Refactor dns part of app to it's own package

dns package changes dns settings through a client, a client is able to:
 • GetRecords to get a list of records of a type and host. For example,
   GetRecords can get all "AAAA" records for host "domain.example.com"
 • CreateRecord will add a dns entry
 • DeleteRecord will delete a record on dnsimple

Update main package to use dns package
 • main package will now create a record and remove all existing records
   when updating
 • Add special case to do nothing if a dns name has only one value

Create utils package
 • Move splitHost into a utils package

dns/dns.go

@@ -0,0 +1,115 @@
+package dns
+
+import (
+	"strconv"
+
+	"git.xbudex.com/buddy/update-dns/utils"
+	"github.com/dnsimple/dnsimple-go/dnsimple"
+	"github.com/pkg/errors"
+)
+
+// Client holds metadata for the dns api client
+type Client struct {
+	client    *dnsimple.Client
+	accountID string
+}
+
+// Record is the type used for a Zone record
+type Record dnsimple.ZoneRecord
+
+// New returns an implementation of a DNS interface
+func New(oauthToken string) *Client {
+	credentials := dnsimple.NewOauthTokenCredentials(oauthToken)
+	client := dnsimple.NewClient(credentials)
+	return &Client{
+		client: client,
+	}
+}
+
+// GetRecords returns all record for a host
+func (d *Client) GetRecords(host, kind string) ([]Record, error) {
+	accountID, err := d.getAccountID()
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to get account id")
+	}
+
+	subdomain, domain, err := utils.SplitHost(host)
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to parse host")
+	}
+
+	records, err := d.client.Zones.ListRecords(accountID, domain, &dnsimple.ZoneRecordListOptions{})
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get list of records")
+	}
+
+	ret := []Record{}
+	for _, record := range records.Data {
+		if record.ZoneID == domain && record.Name == subdomain && record.Type == kind {
+			ret = append(ret, Record(record))
+		}
+	}
+	return ret, nil
+}
+
+// CreateRecord adds a record to DNS
+func (d *Client) CreateRecord(host string, record Record) error {
+	accountID, err := d.getAccountID()
+	if err != nil {
+		return errors.Wrap(err, "unable to get account id")
+	}
+
+	subdomain, domain, err := utils.SplitHost(host)
+	if err != nil {
+		return errors.Wrap(err, "unable to parse host")
+	}
+
+	newRecord := dnsimple.ZoneRecord(record)
+	newRecord.Name = subdomain
+	if _, err := d.client.Zones.CreateRecord(accountID, domain, newRecord); err != nil {
+		return errors.Wrap(err, "could not create record")
+	}
+	return nil
+}
+
+// UpdateRecord returns all record for a host
+func (d *Client) UpdateRecord(record Record) error {
+	accountID, err := d.getAccountID()
+	if err != nil {
+		return errors.Wrap(err, "unable to get account id")
+	}
+
+	if _, err := d.client.Zones.UpdateRecord(accountID, record.ZoneID, record.ID, dnsimple.ZoneRecord(record)); err != nil {
+		return errors.Wrap(err, "could not update record")
+	}
+	return nil
+}
+
+// DeleteRecord returns all record for a host
+func (d *Client) DeleteRecord(record Record) error {
+	accountID, err := d.getAccountID()
+	if err != nil {
+		return errors.Wrap(err, "unable to get account id")
+	}
+
+	if _, err := d.client.Zones.DeleteRecord(accountID, record.ZoneID, record.ID); err != nil {
+		return errors.Wrap(err, "could not delete record")
+	}
+	return nil
+}
+
+func (d *Client) getAccountID() (string, error) {
+	if d.accountID != "" {
+		return d.accountID, nil
+	}
+
+	whoamiResponse, err := d.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")
+	}
+	d.accountID = strconv.Itoa(whoamiResponse.Data.Account.ID)
+	return d.accountID, nil
+}

main.go

@@ -5,11 +5,10 @@ import (
 	"fmt"
 	"net/http"
 	"os"
-	"strconv"
-	"strings"
 	"sync"
 
-	"github.com/dnsimple/dnsimple-go/dnsimple"
+	"git.xbudex.com/buddy/update-dns/dns"
+
 	"github.com/pkg/errors"
 	"github.com/urfave/cli"
 )
@@ -18,6 +17,7 @@ func main() {
 	app := cli.NewApp()
 	app.Name = "update-dns"
 	app.Usage = "update dnsimple with public ip address"
+	app.Version = "0.2.0-dev"
 	app.Action = action
 
 	app.Flags = []cli.Flag{
@@ -64,22 +64,19 @@ func action(context *cli.Context) error {
 		ip = result.IP
 	}()
 
-	var dnSimpleAccountID string
-	var getRecordError error
-	var record *dnsimple.ZoneRecord
-	credentials := dnsimple.NewOauthTokenCredentials(context.String("dnsimple-token"))
-	dnSimpleClient := dnsimple.NewClient(credentials)
+	client := dns.New(context.String("dnsimple-token"))
+	records := []dns.Record{}
+	var getRecordsError error
+
 	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
+		fmt.Println("Getting records")
+		if results, err := client.GetRecords(host, "AAAA"); err != nil {
+			getRecordsError = errors.Wrap(err, "could not get records for host")
+		} else {
+			records = results
 		}
-		record = result
 	}()
 
 	wg.Wait()
@@ -87,93 +84,39 @@ func action(context *cli.Context) error {
 	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")
-		}
+
+	if getRecordsError != nil {
+		return errors.Wrap(getRecordsError, "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 {
+	if len(records) == 1 && records[0].Content == ip {
 		fmt.Printf("%s record for %s already set as %s\n", "AAAA", host, ip)
+		return nil
 	}
-	return nil
-}
-
-type whatIsMyIPResult struct {
-	IP      string `json:ip`
-	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")
+	if err := client.CreateRecord(host, dns.Record{Type: "AAAA", Content: ip}); err != nil {
+		return errors.Wrap(err, "could not create record")
 	}
 
-	records, err := client.Zones.ListRecords(accountID, domain, &dnsimple.ZoneRecordListOptions{})
-	if err != nil {
-		return "", nil, errors.Wrap(err, "could not get list of records")
-	}
+	fmt.Printf("%s record created for %s as %s\n", "AAAA", host, ip)
 
-	for _, record := range records.Data {
-		if record.ZoneID == domain && record.Name == subdomain && record.Type == kind {
-			return accountID, &record, nil
-		}
+	var deleteWG sync.WaitGroup
+	for _, record := range records {
+		deleteWG.Add(1)
+		go func(r dns.Record) {
+			defer deleteWG.Done()
+			fmt.Printf("%s record for %s being deleting %s\n", r.Type, host, r.Content)
+			client.DeleteRecord(r)
+		}(record)
 	}
+	deleteWG.Wait()
 
-	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
+	return 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
+type whatIsMyIPResult struct {
+	IP      string `json:ip`
+	Version string `json:version`
 }
 
 func getIP(url string) (*whatIsMyIPResult, error) {

utils/utils.go

@@ -0,0 +1,25 @@
+package utils
+
+import (
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+// SplitHost returns hostname into domain and subdomain strings.
+// For example:
+//  "some.subdomain.example.com" → ("some.subdomain", "example.com", nil)
+//  "example.com" → ("", "example.com", 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
+}