Add NS1 DNS provider. (#295)

* Add NS1 DNS provider.

Integrates Lego with NS1 using their rest API.
It uses NS1's official Go package as client:

https://github.com/ns1/ns1-go

Signed-off-by: David Calavera <david.calavera@gmail.com>

* Add NS1 to the cli handlers.

Signed-off-by: David Calavera <david.calavera@gmail.com>

cli_handlers.go

@@ -24,6 +24,7 @@ import (
 	"github.com/xenolf/lego/providers/dns/googlecloud"
 	"github.com/xenolf/lego/providers/dns/linode"
 	"github.com/xenolf/lego/providers/dns/namecheap"
+	"github.com/xenolf/lego/providers/dns/ns1"
 	"github.com/xenolf/lego/providers/dns/ovh"
 	"github.com/xenolf/lego/providers/dns/pdns"
 	"github.com/xenolf/lego/providers/dns/rfc2136"
@@ -147,6 +148,8 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 			provider, err = ovh.NewDNSProvider()
 		case "pdns":
 			provider, err = pdns.NewDNSProvider()
+		case "ns1":
+			provider, err = ns1.NewDNSProvider()
 		}
 
 		if err != nil {

providers/dns/ns1/ns1.go

@@ -0,0 +1,97 @@
+// Package ns1 implements a DNS provider for solving the DNS-01 challenge
+// using NS1 DNS.
+package ns1
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/xenolf/lego/acme"
+	"gopkg.in/ns1/ns1-go.v2/rest"
+	"gopkg.in/ns1/ns1-go.v2/rest/model/dns"
+)
+
+// DNSProvider is an implementation of the acme.ChallengeProvider interface.
+type DNSProvider struct {
+	client *rest.Client
+}
+
+// NewDNSProvider returns a DNSProvider instance configured for NS1.
+// Credentials must be passed in the environment variables: NS1_API_KEY.
+func NewDNSProvider() (*DNSProvider, error) {
+	key := os.Getenv("NS1_API_KEY")
+	if key == "" {
+		return nil, fmt.Errorf("NS1 credentials missing")
+	}
+	return NewDNSProviderCredentials(key)
+}
+
+// NewDNSProviderCredentials uses the supplied credentials to return a
+// DNSProvider instance configured for NS1.
+func NewDNSProviderCredentials(key string) (*DNSProvider, error) {
+	if key == "" {
+		return nil, fmt.Errorf("NS1 credentials missing")
+	}
+
+	httpClient := &http.Client{Timeout: time.Second * 10}
+	client := rest.NewClient(httpClient, rest.SetAPIKey(key))
+
+	return &DNSProvider{client}, nil
+}
+
+// Present creates a TXT record to fulfil the dns-01 challenge.
+func (c *DNSProvider) Present(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
+
+	zone, err := c.getHostedZone(domain)
+	if err != nil {
+		return err
+	}
+
+	record := c.newTxtRecord(zone, fqdn, value, ttl)
+	_, err = c.client.Records.Create(record)
+	if err != nil && err != rest.ErrRecordExists {
+		return err
+	}
+
+	return nil
+}
+
+// CleanUp removes the TXT record matching the specified parameters.
+func (c *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _, _ := acme.DNS01Record(domain, keyAuth)
+
+	zone, err := c.getHostedZone(domain)
+	if err != nil {
+		return err
+	}
+
+	name := acme.UnFqdn(fqdn)
+	_, err = c.client.Records.Delete(zone.Zone, name, "TXT")
+	return err
+}
+
+func (c *DNSProvider) getHostedZone(domain string) (*dns.Zone, error) {
+	zone, _, err := c.client.Zones.Get(domain)
+	if err != nil {
+		return nil, err
+	}
+
+	return zone, nil
+}
+
+func (c *DNSProvider) newTxtRecord(zone *dns.Zone, fqdn, value string, ttl int) *dns.Record {
+	name := acme.UnFqdn(fqdn)
+
+	return &dns.Record{
+		Type:   "TXT",
+		Zone:   zone.Zone,
+		Domain: name,
+		TTL:    ttl,
+		Answers: []*dns.Answer{
+			{Rdata: []string{value}},
+		},
+	}
+}

providers/dns/ns1/ns1_test.go

@@ -0,0 +1,67 @@
+package ns1
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	liveTest bool
+	apiKey   string
+	domain   string
+)
+
+func init() {
+	apiKey = os.Getenv("NS1_API_KEY")
+	domain = os.Getenv("NS1_DOMAIN")
+	if len(apiKey) > 0 && len(domain) > 0 {
+		liveTest = true
+	}
+}
+
+func restoreNS1Env() {
+	os.Setenv("NS1_API_KEY", apiKey)
+}
+
+func TestNewDNSProviderValid(t *testing.T) {
+	os.Setenv("NS1_API_KEY", "")
+	_, err := NewDNSProviderCredentials("123")
+	assert.NoError(t, err)
+	restoreNS1Env()
+}
+
+func TestNewDNSProviderMissingCredErr(t *testing.T) {
+	os.Setenv("NS1_API_KEY", "")
+	_, err := NewDNSProvider()
+	assert.EqualError(t, err, "NS1 credentials missing")
+	restoreNS1Env()
+}
+
+func TestLivePresent(t *testing.T) {
+	if !liveTest {
+		t.Skip("skipping live test")
+	}
+
+	provider, err := NewDNSProviderCredentials(apiKey)
+	assert.NoError(t, err)
+
+	err = provider.Present(domain, "", "123d==")
+	assert.NoError(t, err)
+}
+
+func TestLiveCleanUp(t *testing.T) {
+	if !liveTest {
+		t.Skip("skipping live test")
+	}
+
+	time.Sleep(time.Second * 1)
+
+	provider, err := NewDNSProviderCredentials(apiKey)
+	assert.NoError(t, err)
+
+	err = provider.CleanUp(domain, "", "123d==")
+	assert.NoError(t, err)
+}