godyn/pkg/backend/gcp/backend.go
2022-07-06 19:49:07 -07:00

150 lines
3.3 KiB
Go

// Copyright 2017 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gcp
import (
"context"
"fmt"
"sync"
"time"
"golang.org/x/time/rate"
dns "google.golang.org/api/dns/v1"
"git.narnian.us/lordwelch/godyn/pkg/backend"
)
type cloudDNSRecord struct {
dns.ResourceRecordSet
}
func (c cloudDNSRecord) Name() string {
return c.ResourceRecordSet.Name
}
func (c cloudDNSRecord) Type() string {
return c.ResourceRecordSet.Type
}
func (c cloudDNSRecord) Ttl() int64 {
return c.ResourceRecordSet.Ttl
}
func (c cloudDNSRecord) Data() []string {
return c.ResourceRecordSet.Rrdatas
}
// TODO: New backend
type cloudDNSBackend struct {
client *dns.Service
project string
zone string
timeout time.Duration
limiter *rate.Limiter
cache map[string]cloudDNSRecord
mutex *sync.RWMutex
}
func NewCloudDNSBackend(project, zone string) (backend.DNSBackend, error) {
client, err := dns.NewService(context.Background())
if err != nil {
return nil, fmt.Errorf("Could not create Google Cloud DNS client: %v", err)
}
return &cloudDNSBackend{
client: client,
project: project,
zone: zone,
timeout: 5 * time.Second,
limiter: rate.NewLimiter(rate.Every(5*time.Second), 1),
cache: make(map[string]cloudDNSRecord),
mutex: &sync.RWMutex{},
}, nil
}
func (b *cloudDNSBackend) GetRecord(ctx context.Context, dnsName, dnsType string) (backend.DNSRecord, error) {
var (
record dns.ResourceRecordSet
err error
)
if !b.limiter.Allow() {
b.mutex.RLock()
r := b.cache[dnsName+"-"+dnsType]
b.mutex.RUnlock()
if r.Name() != "" {
return r, nil
}
}
b.mutex.Lock()
b.cache = make(map[string]cloudDNSRecord, len(b.cache))
call := b.client.ResourceRecordSets.List(b.project, b.zone)
err = call.Pages(ctx, func(page *dns.ResourceRecordSetsListResponse) error {
for _, v := range page.Rrsets {
if v == nil {
continue
}
if v.Name == dnsName && v.Type == dnsType {
record = *v
}
b.cache[dnsName+"-"+dnsType] = cloudDNSRecord{*v}
}
return nil // NOTE: returning a non-nil error stops pagination.
})
b.mutex.Unlock()
if err != nil {
return nil, err
}
return cloudDNSRecord{record}, nil
}
func (b *cloudDNSBackend) UpdateRecords(ctx context.Context, additions []backend.DNSRecord, deletions []backend.DNSRecord) error {
a := []*dns.ResourceRecordSet{}
d := []*dns.ResourceRecordSet{}
for _, r := range additions {
a = append(a, &dns.ResourceRecordSet{
Name: r.Name(),
Type: r.Type(),
Ttl: r.Ttl(),
Rrdatas: r.Data(),
})
}
for _, r := range deletions {
d = append(d, &dns.ResourceRecordSet{
Name: r.Name(),
Type: r.Type(),
Ttl: r.Ttl(),
Rrdatas: r.Data(),
})
}
change := &dns.Change{
Additions: a,
Deletions: d,
}
_, err := b.client.Changes.Create(b.project, b.zone, change).Context(ctx).Do()
if err != nil {
return err
}
return nil
}