lego/providers/dns/route53/route53.go

227 lines
6.7 KiB
Go

// Package route53 implements a DNS provider for solving the DNS-01 challenge
// using AWS Route 53 DNS.
package route53
import (
"errors"
"fmt"
"math/rand"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/client"
"github.com/aws/aws-sdk-go/aws/request"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/route53"
"github.com/xenolf/lego/acme"
"github.com/xenolf/lego/platform/config/env"
)
// Config is used to configure the creation of the DNSProvider
type Config struct {
MaxRetries int
TTL int
PropagationTimeout time.Duration
PollingInterval time.Duration
HostedZoneID string
}
// NewDefaultConfig returns a default configuration for the DNSProvider
func NewDefaultConfig() *Config {
return &Config{
MaxRetries: env.GetOrDefaultInt("AWS_MAX_RETRIES", 5),
TTL: env.GetOrDefaultInt("AWS_TTL", 10),
PropagationTimeout: env.GetOrDefaultSecond("AWS_PROPAGATION_TIMEOUT", 2*time.Minute),
PollingInterval: env.GetOrDefaultSecond("AWS_POLLING_INTERVAL", 4*time.Second),
HostedZoneID: env.GetOrFile("AWS_HOSTED_ZONE_ID"),
}
}
// DNSProvider implements the acme.ChallengeProvider interface
type DNSProvider struct {
client *route53.Route53
config *Config
}
// customRetryer implements the client.Retryer interface by composing the
// DefaultRetryer. It controls the logic for retrying recoverable request
// errors (e.g. when rate limits are exceeded).
type customRetryer struct {
client.DefaultRetryer
}
// RetryRules overwrites the DefaultRetryer's method.
// It uses a basic exponential backoff algorithm that returns an initial
// delay of ~400ms with an upper limit of ~30 seconds which should prevent
// causing a high number of consecutive throttling errors.
// For reference: Route 53 enforces an account-wide(!) 5req/s query limit.
func (d customRetryer) RetryRules(r *request.Request) time.Duration {
retryCount := r.RetryCount
if retryCount > 7 {
retryCount = 7
}
delay := (1 << uint(retryCount)) * (rand.Intn(50) + 200)
return time.Duration(delay) * time.Millisecond
}
// NewDNSProvider returns a DNSProvider instance configured for the AWS
// Route 53 service.
//
// AWS Credentials are automatically detected in the following locations
// and prioritized in the following order:
// 1. Environment variables: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY,
// AWS_REGION, [AWS_SESSION_TOKEN]
// 2. Shared credentials file (defaults to ~/.aws/credentials)
// 3. Amazon EC2 IAM role
//
// If AWS_HOSTED_ZONE_ID is not set, Lego tries to determine the correct
// public hosted zone via the FQDN.
//
// See also: https://github.com/aws/aws-sdk-go/wiki/configuring-sdk
func NewDNSProvider() (*DNSProvider, error) {
return NewDNSProviderConfig(NewDefaultConfig())
}
// NewDNSProviderConfig takes a given config ans returns a custom configured
// DNSProvider instance
func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
if config == nil {
return nil, errors.New("route53: the configuration of the Route53 DNS provider is nil")
}
r := customRetryer{}
r.NumMaxRetries = config.MaxRetries
sessionCfg := request.WithRetryer(aws.NewConfig(), r)
sess, err := session.NewSessionWithOptions(session.Options{Config: *sessionCfg})
if err != nil {
return nil, err
}
cl := route53.New(sess)
return &DNSProvider{
client: cl,
config: config,
}, nil
}
// Timeout returns the timeout and interval to use when checking for DNS
// propagation.
func (r *DNSProvider) Timeout() (timeout, interval time.Duration) {
return r.config.PropagationTimeout, r.config.PollingInterval
}
// Present creates a TXT record using the specified parameters
func (r *DNSProvider) Present(domain, token, keyAuth string) error {
fqdn, value, _ := acme.DNS01Record(domain, keyAuth)
err := r.changeRecord("UPSERT", fqdn, `"`+value+`"`, r.config.TTL)
if err != nil {
return fmt.Errorf("route53: %v", err)
}
return nil
}
// CleanUp removes the TXT record matching the specified parameters
func (r *DNSProvider) CleanUp(domain, token, keyAuth string) error {
fqdn, value, _ := acme.DNS01Record(domain, keyAuth)
err := r.changeRecord("DELETE", fqdn, `"`+value+`"`, r.config.TTL)
if err != nil {
return fmt.Errorf("route53: %v", err)
}
return nil
}
func (r *DNSProvider) changeRecord(action, fqdn, value string, ttl int) error {
hostedZoneID, err := r.getHostedZoneID(fqdn)
if err != nil {
return fmt.Errorf("failed to determine Route 53 hosted zone ID: %v", err)
}
recordSet := newTXTRecordSet(fqdn, value, ttl)
reqParams := &route53.ChangeResourceRecordSetsInput{
HostedZoneId: aws.String(hostedZoneID),
ChangeBatch: &route53.ChangeBatch{
Comment: aws.String("Managed by Lego"),
Changes: []*route53.Change{
{
Action: aws.String(action),
ResourceRecordSet: recordSet,
},
},
},
}
resp, err := r.client.ChangeResourceRecordSets(reqParams)
if err != nil {
return fmt.Errorf("failed to change record set: %v", err)
}
statusID := resp.ChangeInfo.Id
return acme.WaitFor(r.config.PropagationTimeout, r.config.PollingInterval, func() (bool, error) {
reqParams := &route53.GetChangeInput{
Id: statusID,
}
resp, err := r.client.GetChange(reqParams)
if err != nil {
return false, fmt.Errorf("failed to query change status: %v", err)
}
if aws.StringValue(resp.ChangeInfo.Status) == route53.ChangeStatusInsync {
return true, nil
}
return false, nil
})
}
func (r *DNSProvider) getHostedZoneID(fqdn string) (string, error) {
if r.config.HostedZoneID != "" {
return r.config.HostedZoneID, nil
}
authZone, err := acme.FindZoneByFqdn(fqdn, acme.RecursiveNameservers)
if err != nil {
return "", err
}
// .DNSName should not have a trailing dot
reqParams := &route53.ListHostedZonesByNameInput{
DNSName: aws.String(acme.UnFqdn(authZone)),
}
resp, err := r.client.ListHostedZonesByName(reqParams)
if err != nil {
return "", err
}
var hostedZoneID string
for _, hostedZone := range resp.HostedZones {
// .Name has a trailing dot
if !aws.BoolValue(hostedZone.Config.PrivateZone) && aws.StringValue(hostedZone.Name) == authZone {
hostedZoneID = aws.StringValue(hostedZone.Id)
break
}
}
if len(hostedZoneID) == 0 {
return "", fmt.Errorf("zone %s not found for domain %s", authZone, fqdn)
}
if strings.HasPrefix(hostedZoneID, "/hostedzone/") {
hostedZoneID = strings.TrimPrefix(hostedZoneID, "/hostedzone/")
}
return hostedZoneID, nil
}
func newTXTRecordSet(fqdn, value string, ttl int) *route53.ResourceRecordSet {
return &route53.ResourceRecordSet{
Name: aws.String(fqdn),
Type: aws.String("TXT"),
TTL: aws.Int64(int64(ttl)),
ResourceRecords: []*route53.ResourceRecord{
{Value: aws.String(value)},
},
}
}