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lego/providers/dns/gcloud/googlecloud.go
2020-10-27 12:01:05 +01:00

367 lines
10 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"
"strconv"
"time"
"cloud.google.com/go/compute/metadata"
"github.com/go-acme/lego/v4/challenge/dns01"
"github.com/go-acme/lego/v4/log"
"github.com/go-acme/lego/v4/platform/config/env"
"github.com/go-acme/lego/v4/platform/wait"
"golang.org/x/net/context"
"golang.org/x/oauth2/google"
"google.golang.org/api/dns/v1"
"google.golang.org/api/googleapi"
"google.golang.org/api/option"
)
const (
changeStatusDone = "done"
)
// Environment variables names.
const (
envNamespace = "GCE_"
EnvServiceAccount = envNamespace + "SERVICE_ACCOUNT"
EnvProject = envNamespace + "PROJECT"
EnvAllowPrivateZone = envNamespace + "ALLOW_PRIVATE_ZONE"
EnvDebug = envNamespace + "DEBUG"
EnvTTL = envNamespace + "TTL"
EnvPropagationTimeout = envNamespace + "PROPAGATION_TIMEOUT"
EnvPollingInterval = envNamespace + "POLLING_INTERVAL"
)
// Config is used to configure the creation of the DNSProvider.
type Config struct {
Debug bool
Project string
AllowPrivateZone bool
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(EnvDebug, false),
AllowPrivateZone: env.GetOrDefaultBool(EnvAllowPrivateZone, false),
TTL: env.GetOrDefaultInt(EnvTTL, dns01.DefaultTTL),
PropagationTimeout: env.GetOrDefaultSecond(EnvPropagationTimeout, 180*time.Second),
PollingInterval: env.GetOrDefaultSecond(EnvPollingInterval, 5*time.Second),
}
}
// DNSProvider implements the challenge.Provider interface.
type DNSProvider struct {
config *Config
client *dns.Service
}
// NewDNSProvider returns a DNSProvider instance configured for Google Cloud DNS.
// By default, the project name is auto-detected by using the metadata service,
// it can be overridden using the GCE_PROJECT environment variable.
// A Service Account can be passed in the environment variable: GCE_SERVICE_ACCOUNT
// or by specifying the keyfile location: GCE_SERVICE_ACCOUNT_FILE.
func NewDNSProvider() (*DNSProvider, error) {
// Use a service account file if specified via environment variable.
if saKey := env.GetOrFile(EnvServiceAccount); len(saKey) > 0 {
return NewDNSProviderServiceAccountKey([]byte(saKey))
}
// Use default credentials.
project := env.GetOrDefaultString(EnvProject, autodetectProjectID())
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, errors.New("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: %w", err)
}
config := NewDefaultConfig()
config.Project = project
config.HTTPClient = client
return NewDNSProviderConfig(config)
}
// NewDNSProviderServiceAccountKey uses the supplied service account JSON
// to return a DNSProvider instance configured for Google Cloud DNS.
func NewDNSProviderServiceAccountKey(saKey []byte) (*DNSProvider, error) {
if len(saKey) == 0 {
return nil, errors.New("googlecloud: Service Account is missing")
}
// If GCE_PROJECT is non-empty it overrides the project in the service
// account file.
project := env.GetOrDefaultString(EnvProject, "")
if project == "" {
// read project id from service account file
var datJSON struct {
ProjectID string `json:"project_id"`
}
err := json.Unmarshal(saKey, &datJSON)
if err != nil || datJSON.ProjectID == "" {
return nil, errors.New("googlecloud: project ID not found in Google Cloud Service Account file")
}
project = datJSON.ProjectID
}
conf, err := google.JWTConfigFromJSON(saKey, dns.NdevClouddnsReadwriteScope)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to acquire config: %w", err)
}
client := conf.Client(context.Background())
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, errors.New("googlecloud: Service Account file missing")
}
saKey, err := ioutil.ReadFile(saFile)
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to read Service Account file: %w", err)
}
return NewDNSProviderServiceAccountKey(saKey)
}
// 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")
}
if config.HTTPClient == nil {
return nil, errors.New("googlecloud: unable to create Google Cloud DNS service: client is nil")
}
svc, err := dns.NewService(context.Background(), option.WithHTTPClient(config.HTTPClient))
if err != nil {
return nil, fmt.Errorf("googlecloud: unable to create Google Cloud DNS service: %w", 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(fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %w", err)
}
// Look for existing records.
existingRrSet, err := d.findTxtRecords(zone, fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %w", 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: %w", 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: %w", 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 {
var v *googleapi.Error
if errors.As(err, &v) && v.Code == http.StatusNotFound {
return nil
}
data, _ := json.Marshal(change)
return fmt.Errorf("failed to perform changes [zone %s, change %s]: %w", 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]: %w", 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(fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %w", err)
}
records, err := d.findTxtRecords(zone, fqdn)
if err != nil {
return fmt.Errorf("googlecloud: %w", 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: %w", 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: %w", err)
}
if len(zones.ManagedZones) == 0 {
return "", fmt.Errorf("no matching domain found for domain %s", authZone)
}
for _, z := range zones.ManagedZones {
if z.Visibility == "public" || z.Visibility == "" || (z.Visibility == "private" && d.config.AllowPrivateZone) {
return z.Name, nil
}
}
if d.config.AllowPrivateZone {
return "", fmt.Errorf("no public or private zone found for domain %s", authZone)
}
return "", fmt.Errorf("no public zone found for domain %s", authZone)
}
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
}
func autodetectProjectID() string {
if pid, err := metadata.ProjectID(); err == nil {
return pid
}
return ""
}