Migrate to go-acme/lego.

vendor/github.com/go-acme/lego/providers/dns/duckdns/client.go

@@ -0,0 +1,68 @@
+package duckdns
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"github.com/go-acme/lego/challenge/dns01"
+	"github.com/miekg/dns"
+)
+
+// updateTxtRecord Update the domains TXT record
+// To update the TXT record we just need to make one simple get request.
+// In DuckDNS you only have one TXT record shared with the domain and all sub domains.
+func (d *DNSProvider) updateTxtRecord(domain, token, txt string, clear bool) error {
+	u, _ := url.Parse("https://www.duckdns.org/update")
+
+	mainDomain := getMainDomain(domain)
+	if len(mainDomain) == 0 {
+		return fmt.Errorf("unable to find the main domain for: %s", domain)
+	}
+
+	query := u.Query()
+	query.Set("domains", mainDomain)
+	query.Set("token", token)
+	query.Set("clear", strconv.FormatBool(clear))
+	query.Set("txt", txt)
+	u.RawQuery = query.Encode()
+
+	response, err := d.config.HTTPClient.Get(u.String())
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	bodyBytes, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return err
+	}
+
+	body := string(bodyBytes)
+	if body != "OK" {
+		return fmt.Errorf("request to change TXT record for DuckDNS returned the following result (%s) this does not match expectation (OK) used url [%s]", body, u)
+	}
+	return nil
+}
+
+// DuckDNS only lets you write to your subdomain
+// so it must be in format subdomain.duckdns.org
+// not in format subsubdomain.subdomain.duckdns.org
+// so strip off everything that is not top 3 levels
+func getMainDomain(domain string) string {
+	domain = dns01.UnFqdn(domain)
+
+	split := dns.Split(domain)
+	if strings.HasSuffix(strings.ToLower(domain), "duckdns.org") {
+		if len(split) < 3 {
+			return ""
+		}
+
+		firstSubDomainIndex := split[len(split)-3]
+		return domain[firstSubDomainIndex:]
+	}
+
+	return domain[split[len(split)-1]:]
+}

vendor/github.com/go-acme/lego/providers/dns/duckdns/duckdns.go

@@ -0,0 +1,89 @@
+// Package duckdns implements a DNS provider for solving the DNS-01 challenge using DuckDNS.
+// See http://www.duckdns.org/spec.jsp for more info on updating TXT records.
+package duckdns
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/go-acme/lego/challenge/dns01"
+	"github.com/go-acme/lego/platform/config/env"
+)
+
+// Config is used to configure the creation of the DNSProvider
+type Config struct {
+	Token              string
+	PropagationTimeout time.Duration
+	PollingInterval    time.Duration
+	SequenceInterval   time.Duration
+	HTTPClient         *http.Client
+}
+
+// NewDefaultConfig returns a default configuration for the DNSProvider
+func NewDefaultConfig() *Config {
+	return &Config{
+		PropagationTimeout: env.GetOrDefaultSecond("DUCKDNS_PROPAGATION_TIMEOUT", dns01.DefaultPropagationTimeout),
+		PollingInterval:    env.GetOrDefaultSecond("DUCKDNS_POLLING_INTERVAL", dns01.DefaultPollingInterval),
+		SequenceInterval:   env.GetOrDefaultSecond("DUCKDNS_SEQUENCE_INTERVAL", dns01.DefaultPropagationTimeout),
+		HTTPClient: &http.Client{
+			Timeout: env.GetOrDefaultSecond("DUCKDNS_HTTP_TIMEOUT", 30*time.Second),
+		},
+	}
+}
+
+// DNSProvider adds and removes the record for the DNS challenge
+type DNSProvider struct {
+	config *Config
+}
+
+// NewDNSProvider returns a new DNS provider using
+// environment variable DUCKDNS_TOKEN for adding and removing the DNS record.
+func NewDNSProvider() (*DNSProvider, error) {
+	values, err := env.Get("DUCKDNS_TOKEN")
+	if err != nil {
+		return nil, fmt.Errorf("duckdns: %v", err)
+	}
+
+	config := NewDefaultConfig()
+	config.Token = values["DUCKDNS_TOKEN"]
+
+	return NewDNSProviderConfig(config)
+}
+
+// NewDNSProviderConfig return a DNSProvider instance configured for DuckDNS.
+func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
+	if config == nil {
+		return nil, errors.New("duckdns: the configuration of the DNS provider is nil")
+	}
+
+	if config.Token == "" {
+		return nil, errors.New("duckdns: credentials missing")
+	}
+
+	return &DNSProvider{config: config}, nil
+}
+
+// Present creates a TXT record to fulfill the dns-01 challenge.
+func (d *DNSProvider) Present(domain, token, keyAuth string) error {
+	_, txtRecord := dns01.GetRecord(domain, keyAuth)
+	return d.updateTxtRecord(domain, d.config.Token, txtRecord, false)
+}
+
+// CleanUp clears DuckDNS TXT record
+func (d *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	return d.updateTxtRecord(domain, d.config.Token, "", true)
+}
+
+// Timeout returns the timeout and interval to use when checking for DNS propagation.
+// Adjusting here to cope with spikes in propagation times.
+func (d *DNSProvider) Timeout() (timeout, interval time.Duration) {
+	return d.config.PropagationTimeout, d.config.PollingInterval
+}
+
+// Sequential All DNS challenges for this provider will be resolved sequentially.
+// Returns the interval between each iteration.
+func (d *DNSProvider) Sequential() time.Duration {
+	return d.config.SequenceInterval
+}