etcdmain: resolve DNS hostnames for client and peer URLs

etcd resolves DNS hostnames to IP addresses for client and peer URLs
before creating any listening sockets.

The following messages are logged during startup:

    etcd: Resolving infra0.coreos.com:2380 to 10.0.1.10:2380

Fixes #1991
This commit is contained in:
Kelsey Hightower 2014-12-24 03:29:28 -05:00
parent 289b070aa5
commit 705ec45083
4 changed files with 208 additions and 1 deletions

View File

@ -17,6 +17,7 @@
package etcdmain
import (
"errors"
"flag"
"fmt"
"log"
@ -27,6 +28,7 @@ import (
"github.com/coreos/etcd/etcdserver"
"github.com/coreos/etcd/pkg/cors"
"github.com/coreos/etcd/pkg/flags"
"github.com/coreos/etcd/pkg/netutil"
"github.com/coreos/etcd/pkg/transport"
"github.com/coreos/etcd/version"
)
@ -242,9 +244,17 @@ func (cfg *config) Parse(arguments []string) error {
return err
}
if err := cfg.resolveUrls(); err != nil {
return errors.New("cannot resolve DNS hostnames.")
}
return nil
}
func (cfg *config) resolveUrls() error {
return netutil.ResolveTCPAddrs(cfg.lpurls, cfg.apurls, cfg.lcurls, cfg.acurls)
}
func (cfg config) isNewCluster() bool { return cfg.clusterState.String() == clusterStateFlagNew }
func (cfg config) isProxy() bool { return cfg.proxy.String() != proxyFlagOff }
func (cfg config) isReadonlyProxy() bool { return cfg.proxy.String() == proxyFlagReadonly }

57
pkg/netutil/netutil.go Normal file
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@ -0,0 +1,57 @@
/*
Copyright 2014 CoreOS, Inc.
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 netutil
import (
"log"
"net"
"net/url"
)
var (
// indirection for testing
resolveTCPAddr = net.ResolveTCPAddr
)
// ResolveTCPAddrs is a convenience wrapper for net.ResolveTCPAddr.
// ResolveTCPAddrs resolves all DNS hostnames in-place for the given set of
// url.URLs.
func ResolveTCPAddrs(urls ...[]url.URL) error {
for _, us := range urls {
for i, u := range us {
host, _, err := net.SplitHostPort(u.Host)
if err != nil {
log.Printf("netutil: Could not parse url %s during tcp resolving.", u.Host)
return err
}
if host == "localhost" {
continue
}
if net.ParseIP(host) != nil {
continue
}
tcpAddr, err := resolveTCPAddr("tcp", u.Host)
if err != nil {
log.Printf("netutil: Could not resolve host: %s", u.Host)
return err
}
log.Printf("netutil: Resolving %s to %s", u.Host, tcpAddr.String())
us[i].Host = tcpAddr.String()
}
}
return nil
}

140
pkg/netutil/netutil_test.go Normal file
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@ -0,0 +1,140 @@
/*
Copyright 2014 CoreOS, Inc.
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 netutil
import (
"errors"
"net"
"net/url"
"reflect"
"strconv"
"testing"
)
func TestResolveTCPAddrs(t *testing.T) {
defer func() { resolveTCPAddr = net.ResolveTCPAddr }()
tests := []struct {
urls [][]url.URL
expected [][]url.URL
hostMap map[string]string
hasError bool
}{
{
urls: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "127.0.0.1:4001"},
url.URL{Scheme: "http", Host: "127.0.0.1:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "127.0.0.1:7001"},
url.URL{Scheme: "http", Host: "127.0.0.1:2380"},
},
},
expected: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "127.0.0.1:4001"},
url.URL{Scheme: "http", Host: "127.0.0.1:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "127.0.0.1:7001"},
url.URL{Scheme: "http", Host: "127.0.0.1:2380"},
},
},
},
{
urls: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "infra0.example.com:4001"},
url.URL{Scheme: "http", Host: "infra0.example.com:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "infra0.example.com:7001"},
url.URL{Scheme: "http", Host: "infra0.example.com:2380"},
},
},
expected: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "10.0.1.10:4001"},
url.URL{Scheme: "http", Host: "10.0.1.10:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "10.0.1.10:7001"},
url.URL{Scheme: "http", Host: "10.0.1.10:2380"},
},
},
hostMap: map[string]string{
"infra0.example.com": "10.0.1.10",
},
hasError: false,
},
{
urls: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "infra0.example.com:4001"},
url.URL{Scheme: "http", Host: "infra0.example.com:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "infra0.example.com:7001"},
url.URL{Scheme: "http", Host: "infra0.example.com:2380"},
},
},
hostMap: map[string]string{
"infra0.example.com": "",
},
hasError: true,
},
{
urls: [][]url.URL{
[]url.URL{
url.URL{Scheme: "http", Host: "ssh://infra0.example.com:4001"},
url.URL{Scheme: "http", Host: "ssh://infra0.example.com:2379"},
},
[]url.URL{
url.URL{Scheme: "http", Host: "ssh://infra0.example.com:7001"},
url.URL{Scheme: "http", Host: "ssh://infra0.example.com:2380"},
},
},
hasError: true,
},
}
for _, tt := range tests {
resolveTCPAddr = func(network, addr string) (*net.TCPAddr, error) {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
if tt.hostMap[host] == "" {
return nil, errors.New("cannot resolve host.")
}
i, err := strconv.Atoi(port)
if err != nil {
return nil, err
}
return &net.TCPAddr{IP: net.ParseIP(tt.hostMap[host]), Port: i, Zone: ""}, nil
}
err := ResolveTCPAddrs(tt.urls...)
if tt.hasError {
if err == nil {
t.Errorf("expected error")
}
continue
}
if !reflect.DeepEqual(tt.urls, tt.expected) {
t.Errorf("expected: %v, got %v", tt.expected, tt.urls)
}
}
}

2
test
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@ -15,7 +15,7 @@ COVER=${COVER:-"-cover"}
source ./build
# Hack: gofmt ./ will recursively check the .git directory. So use *.go for gofmt.
TESTABLE_AND_FORMATTABLE="client discovery error etcdctl/command etcdmain etcdserver etcdserver/etcdhttp etcdserver/etcdhttp/httptypes etcdserver/etcdserverpb integration migrate pkg/fileutil pkg/flags pkg/ioutils pkg/types pkg/transport pkg/wait proxy raft rafthttp snap store wal"
TESTABLE_AND_FORMATTABLE="client discovery error etcdctl/command etcdmain etcdserver etcdserver/etcdhttp etcdserver/etcdhttp/httptypes etcdserver/etcdserverpb integration migrate pkg/fileutil pkg/flags pkg/ioutils pkg/netutil pkg/types pkg/transport pkg/wait proxy raft rafthttp snap store wal"
FORMATTABLE="$TESTABLE_AND_FORMATTABLE *.go etcdctl/"
# user has not provided PKG override