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// Package googlecloud implements a DNS provider for solving the DNS-01
// challenge using Google Cloud DNS.
package googlecloud
import (
"fmt"
"io/ioutil"
"os"
"time"
"github.com/xenolf/lego/acme"
"golang.org/x/net/context"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/dns/v1"
)
// DNSProvider is an implementation of the DNSProvider interface.
type DNSProvider struct {
project string
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) {
project := os.Getenv("GCE_PROJECT")
if saFile, ok := os.LookupEnv("GCE_SERVICE_ACCOUNT_FILE"); ok {
return NewDNSProviderServiceAccount(project, saFile)
}
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("Google Cloud project name missing")
}
client, err := google.DefaultClient(context.Background(), dns.NdevClouddnsReadwriteScope)
if err != nil {
return nil, fmt.Errorf("Unable to get Google Cloud client: %v", err)
}
svc, err := dns.New(client)
if err != nil {
return nil, fmt.Errorf("Unable to create Google Cloud DNS service: %v", err)
}
return &DNSProvider{
project: project,
client: svc,
}, nil
}
// NewDNSProviderServiceAccount uses the supplied service account JSON file to
// return a DNSProvider instance configured for Google Cloud DNS.
func NewDNSProviderServiceAccount(project string, saFile string) (*DNSProvider, error) {
if project == "" {
return nil, fmt.Errorf("Google Cloud project name missing")
}
if saFile == "" {
return nil, fmt.Errorf("Google Cloud Service Account file missing")
}
dat, err := ioutil.ReadFile(saFile)
if err != nil {
return nil, fmt.Errorf("Unable to read Service Account file: %v", err)
}
conf, err := google.JWTConfigFromJSON(dat, dns.NdevClouddnsReadwriteScope)
if err != nil {
return nil, fmt.Errorf("Unable to acquire config: %v", err)
}
client := conf.Client(oauth2.NoContext)
svc, err := dns.New(client)
if err != nil {
return nil, fmt.Errorf("Unable to create Google Cloud DNS service: %v", err)
}
return &DNSProvider{
project: project,
client: svc,
}, nil
}
// Present creates a TXT record to fulfil the dns-01 challenge.
func (c *DNSProvider) Present(domain, token, keyAuth string) error {
fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
zone, err := c.getHostedZone(domain)
if err != nil {
return err
}
rec := &dns.ResourceRecordSet{
Name: fqdn,
Rrdatas: []string{value},
Ttl: int64(ttl),
Type: "TXT",
}
change := &dns.Change{
Additions: []*dns.ResourceRecordSet{rec},
}
// Look for existing records.
list, err := c.client.ResourceRecordSets.List(c.project, zone).Name(fqdn).Type("TXT").Do()
if err != nil {
return err
}
if len(list.Rrsets) > 0 {
// Attempt to delete the existing records when adding our new one.
change.Deletions = list.Rrsets
}
chg, err := c.client.Changes.Create(c.project, zone, change).Do()
if err != nil {
return err
}
// wait for change to be acknowledged
for chg.Status == "pending" {
time.Sleep(time.Second)
chg, err = c.client.Changes.Get(c.project, zone, chg.Id).Do()
if err != nil {
return err
}
}
return nil
}
// CleanUp removes the TXT record matching the specified parameters.
func (c *DNSProvider) CleanUp(domain, token, keyAuth string) error {
fqdn, _, _ := acme.DNS01Record(domain, keyAuth)
zone, err := c.getHostedZone(domain)
if err != nil {
return err
}
records, err := c.findTxtRecords(zone, fqdn)
if err != nil {
return err
}
for _, rec := range records {
change := &dns.Change{
Deletions: []*dns.ResourceRecordSet{rec},
}
_, err = c.client.Changes.Create(c.project, zone, change).Do()
if err != nil {
return err
}
}
return nil
}
// Timeout customizes the timeout values used by the ACME package for checking
// DNS record validity.
func (c *DNSProvider) Timeout() (timeout, interval time.Duration) {
return 180 * time.Second, 5 * time.Second
}
// getHostedZone returns the managed-zone
func (c *DNSProvider) getHostedZone(domain string) (string, error) {
authZone, err := acme.FindZoneByFqdn(acme.ToFqdn(domain), acme.RecursiveNameservers)
if err != nil {
return "", err
}
zones, err := c.client.ManagedZones.
List(c.project).
DnsName(authZone).
Do()
if err != nil {
return "", fmt.Errorf("GoogleCloud API call failed: %v", err)
}
if len(zones.ManagedZones) == 0 {
return "", fmt.Errorf("No matching GoogleCloud domain found for domain %s", authZone)
}
return zones.ManagedZones[0].Name, nil
}
func (c *DNSProvider) findTxtRecords(zone, fqdn string) ([]*dns.ResourceRecordSet, error) {
recs, err := c.client.ResourceRecordSets.List(c.project, zone).Do()
if err != nil {
return nil, err
}
found := []*dns.ResourceRecordSet{}
for _, r := range recs.Rrsets {
if r.Type == "TXT" && r.Name == fqdn {
found = append(found, r)
}
}
return found, nil
}
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