lego/providers/dns/gcloud/googlecloud.go
2019-01-02 20:45:17 +01:00

310 lines
8.3 KiB
Go

// Package gcloud implements a DNS provider for solving the DNS-01 challenge using Google Cloud DNS.
package gcloud
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"os"
"strconv"
"time"
"github.com/xenolf/lego/challenge/dns01"
"github.com/xenolf/lego/log"
"github.com/xenolf/lego/platform/config/env"
"github.com/xenolf/lego/platform/wait"
"golang.org/x/net/context"
"golang.org/x/oauth2/google"
"google.golang.org/api/dns/v1"
"google.golang.org/api/googleapi"
)
const (
changeStatusDone = "done"
)
// Config is used to configure the creation of the DNSProvider
type Config struct {
Debug bool
Project 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{
Debug: env.GetOrDefaultBool("GCE_DEBUG", false),
TTL: env.GetOrDefaultInt("GCE_TTL", dns01.DefaultTTL),
PropagationTimeout: env.GetOrDefaultSecond("GCE_PROPAGATION_TIMEOUT", 180*time.Second),
PollingInterval: env.GetOrDefaultSecond("GCE_POLLING_INTERVAL", 5*time.Second),
}
}
// DNSProvider is an implementation of the DNSProvider interface.
type DNSProvider struct {
config *Config
client *dns.Service
}
// NewDNSProvider returns a DNSProvider instance configured for Google Cloud DNS.
// Project name must be passed in the environment variable: GCE_PROJECT.
// A Service Account file can be passed in the environment variable: GCE_SERVICE_ACCOUNT_FILE
func NewDNSProvider() (*DNSProvider, error) {
if saFile, ok := os.LookupEnv("GCE_SERVICE_ACCOUNT_FILE"); ok {
return NewDNSProviderServiceAccount(saFile)
}
project := os.Getenv("GCE_PROJECT")
return NewDNSProviderCredentials(project)
}
// NewDNSProviderCredentials uses the supplied credentials
// to return a DNSProvider instance configured for Google Cloud DNS.
func NewDNSProviderCredentials(project string) (*DNSProvider, error) {
if project == "" {
return nil, fmt.Errorf("googlecloud: project name missing")
}
client, err := google.DefaultClient(context.Background(), dns.NdevClouddnsReadwriteScope)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to get Google Cloud client: %v", err)
}
config := NewDefaultConfig()
config.Project = project
config.HTTPClient = client
return NewDNSProviderConfig(config)
}
// NewDNSProviderServiceAccount uses the supplied service account JSON file
// to return a DNSProvider instance configured for Google Cloud DNS.
func NewDNSProviderServiceAccount(saFile string) (*DNSProvider, error) {
if saFile == "" {
return nil, fmt.Errorf("googlecloud: Service Account file missing")
}
dat, err := ioutil.ReadFile(saFile)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to read Service Account file: %v", err)
}
// read project id from service account file
var datJSON struct {
ProjectID string `json:"project_id"`
}
err = json.Unmarshal(dat, &datJSON)
if err != nil || datJSON.ProjectID == "" {
return nil, fmt.Errorf("googlecloud: project ID not found in Google Cloud Service Account file")
}
project := datJSON.ProjectID
conf, err := google.JWTConfigFromJSON(dat, dns.NdevClouddnsReadwriteScope)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to acquire config: %v", err)
}
client := conf.Client(context.Background())
config := NewDefaultConfig()
config.Project = project
config.HTTPClient = client
return NewDNSProviderConfig(config)
}
// NewDNSProviderConfig return a DNSProvider instance configured for Google Cloud DNS.
func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
if config == nil {
return nil, errors.New("googlecloud: the configuration of the DNS provider is nil")
}
svc, err := dns.New(config.HTTPClient)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to create Google Cloud DNS service: %v", err)
}
return &DNSProvider{config: config, client: svc}, 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)
zone, err := d.getHostedZone(domain)
if err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
// Look for existing records.
existingRrSet, err := d.findTxtRecords(zone, fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
for _, rrSet := range existingRrSet {
var rrd []string
for _, rr := range rrSet.Rrdatas {
data := mustUnquote(rr)
rrd = append(rrd, data)
if data == value {
log.Printf("skip: the record already exists: %s", value)
return nil
}
}
rrSet.Rrdatas = rrd
}
// Attempt to delete the existing records before adding the new one.
if len(existingRrSet) > 0 {
if err = d.applyChanges(zone, &dns.Change{Deletions: existingRrSet}); err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
}
rec := &dns.ResourceRecordSet{
Name: fqdn,
Rrdatas: []string{value},
Ttl: int64(d.config.TTL),
Type: "TXT",
}
// Append existing TXT record data to the new TXT record data
for _, rrSet := range existingRrSet {
for _, rr := range rrSet.Rrdatas {
if rr != value {
rec.Rrdatas = append(rec.Rrdatas, rr)
}
}
}
change := &dns.Change{
Additions: []*dns.ResourceRecordSet{rec},
}
if err = d.applyChanges(zone, change); err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
return nil
}
func (d *DNSProvider) applyChanges(zone string, change *dns.Change) error {
if d.config.Debug {
data, _ := json.Marshal(change)
log.Printf("change (Create): %s", string(data))
}
chg, err := d.client.Changes.Create(d.config.Project, zone, change).Do()
if err != nil {
if v, ok := err.(*googleapi.Error); ok {
if v.Code == http.StatusNotFound {
return nil
}
}
data, _ := json.Marshal(change)
return fmt.Errorf("failed to perform changes [zone %s, change %s]: %v", zone, string(data), err)
}
if chg.Status == changeStatusDone {
return nil
}
chgID := chg.Id
// wait for change to be acknowledged
return wait.For("apply change", 30*time.Second, 3*time.Second, func() (bool, error) {
if d.config.Debug {
data, _ := json.Marshal(change)
log.Printf("change (Get): %s", string(data))
}
chg, err = d.client.Changes.Get(d.config.Project, zone, chgID).Do()
if err != nil {
data, _ := json.Marshal(change)
return false, fmt.Errorf("failed to get changes [zone %s, change %s]: %v", zone, string(data), err)
}
if chg.Status == changeStatusDone {
return true, nil
}
return false, fmt.Errorf("status: %s", chg.Status)
})
}
// CleanUp removes the TXT record matching the specified parameters.
func (d *DNSProvider) CleanUp(domain, token, keyAuth string) error {
fqdn, _ := dns01.GetRecord(domain, keyAuth)
zone, err := d.getHostedZone(domain)
if err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
records, err := d.findTxtRecords(zone, fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
if len(records) == 0 {
return nil
}
_, err = d.client.Changes.Create(d.config.Project, zone, &dns.Change{Deletions: records}).Do()
if err != nil {
return fmt.Errorf("googlecloud: %v", err)
}
return nil
}
// Timeout customizes the timeout values used by the ACME package for checking
// DNS record validity.
func (d *DNSProvider) Timeout() (timeout, interval time.Duration) {
return d.config.PropagationTimeout, d.config.PollingInterval
}
// getHostedZone returns the managed-zone
func (d *DNSProvider) getHostedZone(domain string) (string, error) {
authZone, err := dns01.FindZoneByFqdn(dns01.ToFqdn(domain))
if err != nil {
return "", err
}
zones, err := d.client.ManagedZones.
List(d.config.Project).
DnsName(authZone).
Do()
if err != nil {
return "", fmt.Errorf("API call failed: %v", err)
}
if len(zones.ManagedZones) == 0 {
return "", fmt.Errorf("no matching domain found for domain %s", authZone)
}
return zones.ManagedZones[0].Name, nil
}
func (d *DNSProvider) findTxtRecords(zone, fqdn string) ([]*dns.ResourceRecordSet, error) {
recs, err := d.client.ResourceRecordSets.List(d.config.Project, zone).Name(fqdn).Type("TXT").Do()
if err != nil {
return nil, err
}
return recs.Rrsets, nil
}
func mustUnquote(raw string) string {
clean, err := strconv.Unquote(raw)
if err != nil {
return raw
}
return clean
}