erigon-pulse/cmd/devp2p/dns_route53.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 (
"errors"
"fmt"
"strconv"
"strings"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/route53"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/dnsdisc"
"gopkg.in/urfave/cli.v1"
)
var (
route53AccessKeyFlag = cli.StringFlag{
Name: "access-key-id",
Usage: "AWS Access Key ID",
EnvVar: "AWS_ACCESS_KEY_ID",
}
route53AccessSecretFlag = cli.StringFlag{
Name: "access-key-secret",
Usage: "AWS Access Key Secret",
EnvVar: "AWS_SECRET_ACCESS_KEY",
}
route53ZoneIDFlag = cli.StringFlag{
Name: "zone-id",
Usage: "Route53 Zone ID",
}
)
type route53Client struct {
api *route53.Route53
zoneID string
}
// newRoute53Client sets up a Route53 API client from command line flags.
func newRoute53Client(ctx *cli.Context) *route53Client {
akey := ctx.String(route53AccessKeyFlag.Name)
asec := ctx.String(route53AccessSecretFlag.Name)
if akey == "" || asec == "" {
exit(fmt.Errorf("need Route53 Access Key ID and secret proceed"))
}
config := &aws.Config{Credentials: credentials.NewStaticCredentials(akey, asec, "")}
session, err := session.NewSession(config)
if err != nil {
exit(fmt.Errorf("can't create AWS session: %v", err))
}
return &route53Client{
api: route53.New(session),
zoneID: ctx.String(route53ZoneIDFlag.Name),
}
}
// deploy uploads the given tree to Route53.
func (c *route53Client) deploy(name string, t *dnsdisc.Tree) error {
if err := c.checkZone(name); err != nil {
return err
}
// Compute DNS changes.
records := t.ToTXT(name)
changes, err := c.computeChanges(name, records)
if err != nil {
return err
}
if len(changes) == 0 {
log.Info("No DNS changes needed")
return nil
}
// Submit change request.
log.Info(fmt.Sprintf("Submitting %d changes to Route53", len(changes)))
batch := new(route53.ChangeBatch)
batch.SetChanges(changes)
batch.SetComment(fmt.Sprintf("enrtree update of %s at seq %d", name, t.Seq()))
req := &route53.ChangeResourceRecordSetsInput{HostedZoneId: &c.zoneID, ChangeBatch: batch}
resp, err := c.api.ChangeResourceRecordSets(req)
if err != nil {
return err
}
// Wait for the change to be applied.
log.Info(fmt.Sprintf("Waiting for change request %s", *resp.ChangeInfo.Id))
wreq := &route53.GetChangeInput{Id: resp.ChangeInfo.Id}
return c.api.WaitUntilResourceRecordSetsChanged(wreq)
}
// checkZone verifies zone information for the given domain.
func (c *route53Client) checkZone(name string) (err error) {
if c.zoneID == "" {
c.zoneID, err = c.findZoneID(name)
}
return err
}
// findZoneID searches for the Zone ID containing the given domain.
func (c *route53Client) findZoneID(name string) (string, error) {
log.Info(fmt.Sprintf("Finding Route53 Zone ID for %s", name))
var req route53.ListHostedZonesByNameInput
for {
resp, err := c.api.ListHostedZonesByName(&req)
if err != nil {
return "", err
}
for _, zone := range resp.HostedZones {
if isSubdomain(name, *zone.Name) {
return *zone.Id, nil
}
}
if !*resp.IsTruncated {
break
}
req.DNSName = resp.NextDNSName
req.HostedZoneId = resp.NextHostedZoneId
}
return "", errors.New("can't find zone ID for " + name)
}
// computeChanges creates DNS changes for the given record.
func (c *route53Client) computeChanges(name string, records map[string]string) ([]*route53.Change, 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
// Get existing records.
existing, err := c.collectRecords(name)
if err != nil {
return nil, err
}
log.Info(fmt.Sprintf("Found %d TXT records", len(existing)))
var changes []*route53.Change
for path, val := range records {
ttl := 1
if path != name {
ttl = 2147483647
}
prevRecords, exists := existing[path]
prevValue := combineTXT(prevRecords)
if !exists {
// Entry is unknown, push a new one
log.Info(fmt.Sprintf("Creating %s = %q", path, val))
changes = append(changes, newTXTChange("CREATE", path, ttl, splitTXT(val)))
} else if prevValue != val {
// Entry already exists, only change its content.
log.Info(fmt.Sprintf("Updating %s from %q to %q", path, prevValue, val))
changes = append(changes, newTXTChange("UPSERT", path, ttl, splitTXT(val)))
} else {
log.Info(fmt.Sprintf("Skipping %s = %q", path, val))
}
}
// Iterate over the old records and delete anything stale.
for path, values := range existing {
if _, ok := records[path]; ok {
continue
}
// Stale entry, nuke it.
log.Info(fmt.Sprintf("Deleting %s = %q", path, combineTXT(values)))
changes = append(changes, newTXTChange("DELETE", path, 1, values))
}
return changes, nil
}
// collectRecords collects all TXT records below the given name.
func (c *route53Client) collectRecords(name string) (map[string][]string, error) {
log.Info(fmt.Sprintf("Retrieving existing TXT records on %s (%s)", name, c.zoneID))
var req route53.ListResourceRecordSetsInput
req.SetHostedZoneId(c.zoneID)
existing := make(map[string][]string)
err := c.api.ListResourceRecordSetsPages(&req, func(resp *route53.ListResourceRecordSetsOutput, last bool) bool {
for _, set := range resp.ResourceRecordSets {
if !isSubdomain(*set.Name, name) || *set.Type != "TXT" {
continue
}
name := strings.TrimSuffix(*set.Name, ".")
for _, rec := range set.ResourceRecords {
existing[name] = append(existing[name], *rec.Value)
}
}
return true
})
return existing, err
}
// newTXTChange creates a change to a TXT record.
func newTXTChange(action, name string, ttl int, values []string) *route53.Change {
var c route53.Change
var r route53.ResourceRecordSet
var rrs []*route53.ResourceRecord
for _, val := range values {
rr := new(route53.ResourceRecord)
rr.SetValue(val)
rrs = append(rrs, rr)
}
r.SetType("TXT")
r.SetName(name)
r.SetTTL(int64(ttl))
r.SetResourceRecords(rrs)
c.SetAction(action)
c.SetResourceRecordSet(&r)
return &c
}
// isSubdomain returns true if name is a subdomain of domain.
func isSubdomain(name, domain string) bool {
domain = strings.TrimSuffix(domain, ".")
name = strings.TrimSuffix(name, ".")
return strings.HasSuffix("."+name, "."+domain)
}
// combineTXT concatenates the given quoted strings into a single unquoted string.
func combineTXT(values []string) string {
result := ""
for _, v := range values {
if v[0] == '"' {
v = v[1 : len(v)-1]
}
result += v
}
return result
}
// splitTXT splits value into a list of quoted 255-character strings.
func splitTXT(value string) []string {
var result []string
for len(value) > 0 {
rlen := len(value)
if rlen > 253 {
rlen = 253
}
result = append(result, strconv.Quote(value[:rlen]))
value = value[rlen:]
}
return result
}