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// Copyright 2016 The Roughtime 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 main
import (
"encoding/json"
"flag"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"time"
"roughtime.googlesource.com/go/client/monotime"
"roughtime.googlesource.com/go/config"
)
var (
chainFile = flag.String("chain-file", "roughtime-chain.json", "The name of a file in which the query chain will be maintained")
maxChainSize = flag.Int("max-chain-size", 128, "The maximum number of entries to maintain in the chain file")
serversFile = flag.String("servers-file", "roughtime-servers.json", "The name of a file that lists trusted Roughtime servers")
)
const (
// defaultServerQuorum is the default number of overlapping responses
// that are required to establish the current time.
defaultServerQuorum = 3
)
func do() error {
flag.Parse()
serversData, err := ioutil.ReadFile(*serversFile)
if err != nil {
return err
}
servers, numServersSkipped, err := LoadServers(serversData)
if err != nil {
return err
}
if numServersSkipped > 0 {
fmt.Fprintf(os.Stderr, "Ignoring %d unsupported servers\n", numServersSkipped)
}
chain := &config.Chain{}
chainData, err := ioutil.ReadFile(*chainFile)
if err == nil {
if chain, err = LoadChain(chainData); err != nil {
return err
}
} else if !os.IsNotExist(err) {
return err
}
quorum := defaultServerQuorum
if quorum > len(servers) {
fmt.Fprintf(os.Stderr, "Quorum set to %d servers because not enough valid servers were found to meet the default (%d)!\n", len(servers), quorum)
quorum = len(servers)
}
var client Client
result, err := client.EstablishTime(chain, quorum, servers)
if err != nil {
return err
}
for serverName, err := range result.ServerErrors {
fmt.Fprintf(os.Stderr, "Failed to query %q: %s\n", serverName, err)
}
maxLenServerName := 0
for name := range result.ServerInfo {
if len(name) > maxLenServerName {
maxLenServerName = len(name)
}
}
for name, info := range result.ServerInfo {
fmt.Printf("%s:%s %d–%d (answered in %s)\n", name, strings.Repeat(" ", maxLenServerName-len(name)), info.Min, info.Max, info.QueryDuration)
}
if result.MonoUTCDelta == nil {
fmt.Fprintf(os.Stderr, "Failed to get %d servers to agree on the time.\n", quorum)
} else {
nowUTC := time.Unix(0, int64(monotime.Now()+*result.MonoUTCDelta))
nowRealTime := time.Now()
fmt.Printf("real-time delta: %s\n", nowRealTime.Sub(nowUTC))
}
// TODO: if result.OutOfRangeAnswer is set then cap the chain and
// upload it.
if result.OutOfRangeAnswer {
fmt.Fprintf(os.Stderr, "One or more of the answers was significantly out of range.\n")
}
trimChain(chain, *maxChainSize)
chainBytes, err := json.MarshalIndent(chain, "", " ")
if err != nil {
return err
}
tempFile, err := ioutil.TempFile(filepath.Dir(*chainFile), filepath.Base(*chainFile))
if err != nil {
return err
}
defer tempFile.Close()
if _, err := tempFile.Write(chainBytes); err != nil {
return err
}
if err := os.Rename(tempFile.Name(), *chainFile); err != nil {
return err
}
return nil
}
func main() {
if err := do(); err != nil {
fmt.Fprintf(os.Stderr, "%s\n", err)
os.Exit(1)
}
}