Added multiple DNS provider support

acme/client.go

@@ -104,14 +104,18 @@ func (c *Client) SetChallengeProvider(challenge Challenge, p ChallengeProvider)
 		c.solvers[challenge] = &httpChallenge{jws: c.jws, validate: validate, provider: p}
 	case TLSSNI01:
 		c.solvers[challenge] = &tlsSNIChallenge{jws: c.jws, validate: validate, provider: p}
-	case DNS01:
-		c.solvers[challenge] = &dnsChallenge{jws: c.jws, validate: validate, provider: p}
 	default:
 		return fmt.Errorf("Unknown challenge %v", challenge)
 	}
 	return nil
 }
 
+// SetChallengeProvidersDNS specifies one or more provider p that can solve the DNS challenge type.
+func (c *Client) SetChallengeProvidersDNS(challenge Challenge, p []ChallengeProvider) error {
+	c.solvers[challenge] = &dnsChallenge{jws: c.jws, validate: validate, providers: p}
+	return nil
+}
+
 // SetHTTPAddress specifies a custom interface:port to be used for HTTP based challenges.
 // If this option is not used, the default port 80 and all interfaces will be used.
 // To only specify a port and no interface use the ":port" notation.

acme/dns_challenge.go

@@ -9,7 +9,6 @@ import (
 	"net"
 	"strings"
 	"time"
-
 	"github.com/miekg/dns"
 	"golang.org/x/net/publicsuffix"
 )
@@ -69,13 +68,13 @@ func DNS01Record(domain, keyAuth string) (fqdn string, value string, ttl int) {
 type dnsChallenge struct {
 	jws      *jws
 	validate validateFunc
-	provider ChallengeProvider
+	providers []ChallengeProvider
 }
 
 func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	logf("[INFO][%s] acme: Trying to solve DNS-01", domain)
 
-	if s.provider == nil {
+	if len(s.providers) == 0 {
 		return errors.New("No DNS Provider configured")
 	}
 
@@ -85,14 +84,22 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 		return err
 	}
 
-	err = s.provider.Present(domain, chlng.Token, keyAuth)
-	if err != nil {
-		return fmt.Errorf("Error presenting token: %s", err)
+	for _, v := range s.providers {
+		err = v.Present(domain, chlng.Token, keyAuth)
+
+		if err != nil {
+			return fmt.Errorf("Error presenting token: %s", err)
+		}
 	}
+
 	defer func() {
-		err := s.provider.CleanUp(domain, chlng.Token, keyAuth)
-		if err != nil {
-			log.Printf("Error cleaning up %s: %v ", domain, err)
+
+		for _, v := range s.providers {
+			err := v.CleanUp(domain, chlng.Token, keyAuth)
+
+			if err != nil {
+				log.Printf("Error cleaning up %s: %v ", domain, err)
+			}
 		}
 	}()
 
@@ -101,16 +108,30 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	logf("[INFO][%s] Checking DNS record propagation using %+v", domain, RecursiveNameservers)
 
 	var timeout, interval time.Duration
-	switch provider := s.provider.(type) {
-	case ChallengeProviderTimeout:
-		timeout, interval = provider.Timeout()
-	default:
-		timeout, interval = 60*time.Second, 2*time.Second
+
+	for _, v := range s.providers {
+		var tiou, inter time.Duration
+
+		switch provider := v.(type) {
+			case ChallengeProviderTimeout:
+				tiou, inter = provider.Timeout()
+			default:
+				tiou, inter = 60*time.Second, 2*time.Second
+		}
+
+		// Check if interval or timeout is greater, we take the highest number
+		if timeout < tiou {
+			timeout = tiou
+		}
+		if interval < inter {
+			interval = inter
+		}
 	}
 
 	err = WaitFor(timeout, interval, func() (bool, error) {
 		return PreCheckDNS(fqdn, value)
 	})
+
 	if err != nil {
 		return err
 	}

cli.go

@@ -196,6 +196,9 @@ Here is an example bash command using the CloudFlare DNS provider:
     CLOUDFLARE_API_KEY=b9841238feb177a84330febba8a83208921177bffe733 \
     lego --dns cloudflare --domains www.example.com --email [email protected] run
 
+Here is an example bash command using multiple DNS provider:
+  $ lego --dns gcloud,route53 --domains www.example.com --email [email protected] run
+
 `)
 
 	w := tabwriter.NewWriter(os.Stdout, 0, 8, 1, '\t', 0)

cli_handlers.go

@@ -114,12 +114,20 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 	}
 
 	if c.GlobalIsSet("dns") {
-    provider, err := dns.NewDNSChallengeProviderByName(c.GlobalString("dns"))
-		if err != nil {
-			logger().Fatal(err)
+		// Get providers
+		var providers []acme.ChallengeProvider
+
+		for _, v := range strings.Split(c.GlobalString("dns"), ",") {
+			provider, err := dns.NewDNSChallengeProviderByName(v)
+
+			if err != nil {
+				logger().Fatal(err)
+			}
+
+			providers = append(providers, provider)
 		}
 
-		client.SetChallengeProvider(acme.DNS01, provider)
+		client.SetChallengeProvidersDNS(acme.DNS01, providers)
 
 		// --dns=foo indicates that the user specifically want to do a DNS challenge
 		// infer that the user also wants to exclude all other challenges