text: // Package vultr implements a DNS provider for solving the DNS-01 challenge using the vultr DNS.
  // See https://www.vultr.com/api/#dns
  package vultr
  
  import (
  	"crypto/tls"
  	"errors"
  	"fmt"
  	"net/http"
  	"strings"
  	"time"
  
  	vultr "github.com/JamesClonk/vultr/lib"
  	"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 {
  	APIKey             string
  	PropagationTimeout time.Duration
  	PollingInterval    time.Duration
  	TTL                int
  	HTTPClient         *http.Client
  }
  
  // NewDefaultConfig returns a default configuration for the DNSProvider
  func NewDefaultConfig() *Config {
  	return &Config{
  		TTL:                env.GetOrDefaultInt("VULTR_TTL", dns01.DefaultTTL),
  		PropagationTimeout: env.GetOrDefaultSecond("VULTR_PROPAGATION_TIMEOUT", dns01.DefaultPropagationTimeout),
  		PollingInterval:    env.GetOrDefaultSecond("VULTR_POLLING_INTERVAL", dns01.DefaultPollingInterval),
  		HTTPClient: &http.Client{
  			Timeout: env.GetOrDefaultSecond("VULTR_HTTP_TIMEOUT", 0),
  			// from Vultr Client
  			Transport: &http.Transport{
  				TLSNextProto: make(map[string]func(string, *tls.Conn) http.RoundTripper),
  			},
  		},
  	}
  }
  
  // DNSProvider is an implementation of the acme.ChallengeProvider interface.
  type DNSProvider struct {
  	config *Config
  	client *vultr.Client
  }
  
  // NewDNSProvider returns a DNSProvider instance with a configured Vultr client.
  // Authentication uses the VULTR_API_KEY environment variable.
  func NewDNSProvider() (*DNSProvider, error) {
  	values, err := env.Get("VULTR_API_KEY")
  	if err != nil {
  		return nil, fmt.Errorf("vultr: %v", err)
  	}
  
  	config := NewDefaultConfig()
  	config.APIKey = values["VULTR_API_KEY"]
  
  	return NewDNSProviderConfig(config)
  }
  
  // NewDNSProviderConfig return a DNSProvider instance configured for Vultr.
  func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("vultr: the configuration of the DNS provider is nil")
  	}
  
  	if config.APIKey == "" {
  		return nil, fmt.Errorf("vultr: credentials missing")
  	}
  
  	options := &vultr.Options{
  		HTTPClient: config.HTTPClient,
  	}
  	client := vultr.NewClient(config.APIKey, options)
  
  	return &DNSProvider{client: client, config: config}, nil
  }
  
  // Present creates a TXT record to fulfill the DNS-01 challenge.
  func (d *DNSProvider) Present(domain, token, keyAuth string) error {
  	fqdn, value := dns01.GetRecord(domain, keyAuth)
  
  	zoneDomain, err := d.getHostedZone(domain)
  	if err != nil {
  		return fmt.Errorf("vultr: %v", err)
  	}
  
  	name := d.extractRecordName(fqdn, zoneDomain)
  
  	err = d.client.CreateDNSRecord(zoneDomain, name, "TXT", `"`+value+`"`, 0, d.config.TTL)
  	if err != nil {
  		return fmt.Errorf("vultr: API call failed: %v", err)
  	}
  
  	return nil
  }
  
  // CleanUp removes the TXT record matching the specified parameters.
  func (d *DNSProvider) CleanUp(domain, token, keyAuth string) error {
  	fqdn, _ := dns01.GetRecord(domain, keyAuth)
  
  	zoneDomain, records, err := d.findTxtRecords(domain, fqdn)
  	if err != nil {
  		return fmt.Errorf("vultr: %v", err)
  	}
  
  	var allErr []string
  	for _, rec := range records {
  		err := d.client.DeleteDNSRecord(zoneDomain, rec.RecordID)
  		if err != nil {
  			allErr = append(allErr, err.Error())
  		}
  	}
  
  	if len(allErr) > 0 {
  		return errors.New(strings.Join(allErr, ": "))
  	}
  
  	return nil
  }
  
  // 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
  }
  
  func (d *DNSProvider) getHostedZone(domain string) (string, error) {
  	domains, err := d.client.GetDNSDomains()
  	if err != nil {
  		return "", fmt.Errorf("API call failed: %v", err)
  	}
  
  	var hostedDomain vultr.DNSDomain
  	for _, dom := range domains {
  		if strings.HasSuffix(domain, dom.Domain) {
  			if len(dom.Domain) > len(hostedDomain.Domain) {
  				hostedDomain = dom
  			}
  		}
  	}
  	if hostedDomain.Domain == "" {
  		return "", fmt.Errorf("no matching Vultr domain found for domain %s", domain)
  	}
  
  	return hostedDomain.Domain, nil
  }
  
  func (d *DNSProvider) findTxtRecords(domain, fqdn string) (string, []vultr.DNSRecord, error) {
  	zoneDomain, err := d.getHostedZone(domain)
  	if err != nil {
  		return "", nil, err
  	}
  
  	var records []vultr.DNSRecord
  	result, err := d.client.GetDNSRecords(zoneDomain)
  	if err != nil {
  		return "", records, fmt.Errorf("API call has failed: %v", err)
  	}
  
  	recordName := d.extractRecordName(fqdn, zoneDomain)
  	for _, record := range result {
  		if record.Type == "TXT" && record.Name == recordName {
  			records = append(records, record)
  		}
  	}
  
  	return zoneDomain, records, nil
  }
  
  func (d *DNSProvider) extractRecordName(fqdn, domain string) string {
  	name := dns01.UnFqdn(fqdn)
  	if idx := strings.Index(name, "."+domain); idx != -1 {
  		return name[:idx]
  	}
  	return name
  }
  