104 lines
3.0 KiB
Go
104 lines
3.0 KiB
Go
// Copyright 2015 The etcd Authors
|
|
//
|
|
// 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 discovery
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
"strings"
|
|
|
|
"github.com/coreos/etcd/pkg/types"
|
|
)
|
|
|
|
var (
|
|
// indirection for testing
|
|
lookupSRV = net.LookupSRV
|
|
resolveTCPAddr = net.ResolveTCPAddr
|
|
)
|
|
|
|
// SRVGetCluster gets the cluster information via DNS discovery.
|
|
// TODO(barakmich): Currently ignores priority and weight (as they don't make as much sense for a bootstrap)
|
|
// Also doesn't do any lookups for the token (though it could)
|
|
// Also sees each entry as a separate instance.
|
|
func SRVGetCluster(name, dns string, defaultToken string, apurls types.URLs) (string, string, error) {
|
|
var (
|
|
stringParts []string
|
|
tcpAPUrls []string
|
|
)
|
|
tempName := int(0)
|
|
|
|
// First, resolve the apurls
|
|
for _, url := range apurls {
|
|
tcpAddr, err := resolveTCPAddr("tcp", url.Host)
|
|
if err != nil {
|
|
plog.Errorf("couldn't resolve host %s during SRV discovery", url.Host)
|
|
return "", "", err
|
|
}
|
|
tcpAPUrls = append(tcpAPUrls, tcpAddr.String())
|
|
}
|
|
|
|
updateNodeMap := func(service, prefix string) error {
|
|
_, addrs, err := lookupSRV(service, "tcp", dns)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
for _, srv := range addrs {
|
|
port := fmt.Sprintf("%d", srv.Port)
|
|
host := net.JoinHostPort(srv.Target, port)
|
|
tcpAddr, err := resolveTCPAddr("tcp", host)
|
|
if err != nil {
|
|
plog.Warningf("couldn't resolve host %s during SRV discovery", host)
|
|
continue
|
|
}
|
|
n := ""
|
|
for _, url := range tcpAPUrls {
|
|
if url == tcpAddr.String() {
|
|
n = name
|
|
}
|
|
}
|
|
if n == "" {
|
|
n = fmt.Sprintf("%d", tempName)
|
|
tempName++
|
|
}
|
|
// SRV records have a trailing dot but URL shouldn't.
|
|
shortHost := strings.TrimSuffix(srv.Target, ".")
|
|
urlHost := net.JoinHostPort(shortHost, port)
|
|
stringParts = append(stringParts, fmt.Sprintf("%s=%s%s", n, prefix, urlHost))
|
|
plog.Noticef("got bootstrap from DNS for %s at %s%s", service, prefix, urlHost)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
failCount := 0
|
|
err := updateNodeMap("etcd-server-ssl", "https://")
|
|
srvErr := make([]string, 2)
|
|
if err != nil {
|
|
srvErr[0] = fmt.Sprintf("error querying DNS SRV records for _etcd-server-ssl %s", err)
|
|
failCount++
|
|
}
|
|
err = updateNodeMap("etcd-server", "http://")
|
|
if err != nil {
|
|
srvErr[1] = fmt.Sprintf("error querying DNS SRV records for _etcd-server %s", err)
|
|
failCount++
|
|
}
|
|
if failCount == 2 {
|
|
plog.Warningf(srvErr[0])
|
|
plog.Warningf(srvErr[1])
|
|
plog.Errorf("SRV discovery failed: too many errors querying DNS SRV records")
|
|
return "", "", err
|
|
}
|
|
return strings.Join(stringParts, ","), defaultToken, nil
|
|
}
|