Official Go implementation of the Ethereum protocol
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go-ethereum/cmd/devp2p/dns_cloudflare.go

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// Copyright 2019 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package main
import (
"context"
"errors"
"fmt"
"strings"
"github.com/cloudflare/cloudflare-go"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/dnsdisc"
"github.com/urfave/cli/v2"
)
var (
cloudflareTokenFlag = &cli.StringFlag{
Name: "token",
Usage: "CloudFlare API token",
EnvVars: []string{"CLOUDFLARE_API_TOKEN"},
}
cloudflareZoneIDFlag = &cli.StringFlag{
Name: "zoneid",
Usage: "CloudFlare Zone ID (optional)",
}
)
type cloudflareClient struct {
*cloudflare.API
zoneID string
}
// newCloudflareClient sets up a CloudFlare API client from command line flags.
func newCloudflareClient(ctx *cli.Context) *cloudflareClient {
token := ctx.String(cloudflareTokenFlag.Name)
if token == "" {
exit(errors.New("need cloudflare API token to proceed"))
}
api, err := cloudflare.NewWithAPIToken(token)
if err != nil {
exit(fmt.Errorf("can't create Cloudflare client: %v", err))
}
return &cloudflareClient{
API: api,
zoneID: ctx.String(cloudflareZoneIDFlag.Name),
}
}
// deploy uploads the given tree to CloudFlare DNS.
func (c *cloudflareClient) deploy(name string, t *dnsdisc.Tree) error {
if err := c.checkZone(name); err != nil {
return err
}
records := t.ToTXT(name)
return c.uploadRecords(name, records)
}
// checkZone verifies permissions on the CloudFlare DNS Zone for name.
func (c *cloudflareClient) checkZone(name string) error {
if c.zoneID == "" {
log.Info(fmt.Sprintf("Finding CloudFlare zone ID for %s", name))
id, err := c.ZoneIDByName(name)
if err != nil {
return err
}
c.zoneID = id
}
log.Info(fmt.Sprintf("Checking Permissions on zone %s", c.zoneID))
zone, err := c.ZoneDetails(context.Background(), c.zoneID)
if err != nil {
return err
}
if !strings.HasSuffix(name, "."+zone.Name) {
return fmt.Errorf("CloudFlare zone name %q does not match name %q to be deployed", zone.Name, name)
}
needPerms := map[string]bool{"#zone:edit": false, "#zone:read": false}
for _, perm := range zone.Permissions {
if _, ok := needPerms[perm]; ok {
needPerms[perm] = true
}
}
for _, ok := range needPerms {
if !ok {
return fmt.Errorf("wrong permissions on zone %s: %v", c.zoneID, needPerms)
}
}
return nil
}
// uploadRecords updates the TXT records at a particular subdomain. All non-root records
// will have a TTL of "infinity" and all existing records not in the new map will be
// nuked!
func (c *cloudflareClient) uploadRecords(name string, records map[string]string) error {
// Convert all names to lowercase.
lrecords := make(map[string]string, len(records))
for name, r := range records {
lrecords[strings.ToLower(name)] = r
}
records = lrecords
log.Info(fmt.Sprintf("Retrieving existing TXT records on %s", name))
entries, _, err := c.ListDNSRecords(context.Background(), cloudflare.ZoneIdentifier(c.zoneID), cloudflare.ListDNSRecordsParams{Type: "TXT"})
if err != nil {
return err
}
existing := make(map[string]cloudflare.DNSRecord)
for _, entry := range entries {
if !strings.HasSuffix(entry.Name, name) {
continue
}
existing[strings.ToLower(entry.Name)] = entry
}
// Iterate over the new records and inject anything missing.
log.Info("Updating DNS entries")
created := 0
updated := 0
skipped := 0
for path, val := range records {
old, exists := existing[path]
if !exists {
// Entry is unknown, push a new one to Cloudflare.
log.Debug(fmt.Sprintf("Creating %s = %q", path, val))
created++
ttl := rootTTL
if path != name {
ttl = treeNodeTTLCloudflare // Max TTL permitted by Cloudflare
}
record := cloudflare.CreateDNSRecordParams{Type: "TXT", Name: path, Content: val, TTL: ttl}
_, err = c.CreateDNSRecord(context.Background(), cloudflare.ZoneIdentifier(c.zoneID), record)
} else if old.Content != val {
// Entry already exists, only change its content.
log.Info(fmt.Sprintf("Updating %s from %q to %q", path, old.Content, val))
updated++
record := cloudflare.UpdateDNSRecordParams{
Type: old.Type,
Name: old.Name,
Content: val,
Data: old.Data,
ID: old.ID,
Priority: old.Priority,
TTL: old.TTL,
Proxied: old.Proxied,
Tags: old.Tags,
}
_, err = c.UpdateDNSRecord(context.Background(), cloudflare.ZoneIdentifier(c.zoneID), record)
} else {
skipped++
log.Debug(fmt.Sprintf("Skipping %s = %q", path, val))
}
if err != nil {
return fmt.Errorf("failed to publish %s: %v", path, err)
}
}
log.Info("Updated DNS entries", "new", created, "updated", updated, "untouched", skipped)
// Iterate over the old records and delete anything stale.
deleted := 0
log.Info("Deleting stale DNS entries")
for path, entry := range existing {
if _, ok := records[path]; ok {
continue
}
// Stale entry, nuke it.
log.Debug(fmt.Sprintf("Deleting %s = %q", path, entry.Content))
deleted++
if err := c.DeleteDNSRecord(context.Background(), cloudflare.ZoneIdentifier(c.zoneID), entry.ID); err != nil {
return fmt.Errorf("failed to delete %s: %v", path, err)
}
}
log.Info("Deleted stale DNS entries", "count", deleted)
return nil
}