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Verify rsync protocol version match prior to proceeding - Rebased on current master. #71

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Jul 2, 2020
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31 changes: 31 additions & 0 deletions cmd/coder/sync.go
Original file line number Diff line number Diff line change
@@ -1,7 +1,11 @@
package main

import (
"bytes"
"fmt"
"log"
"os"
"os/exec"
"path/filepath"
"strings"

Expand Down Expand Up @@ -29,6 +33,23 @@ func (cmd *syncCmd) RegisterFlags(fl *pflag.FlagSet) {
fl.BoolVarP(&cmd.init, "init", "i", false, "do initial transfer and exit")
}

// version returns local rsync protocol version as a string.
func (_ *syncCmd) version() string {
cmd := exec.Command("rsync", "--version")
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}

firstLine, err := bytes.NewBuffer(out).ReadString('\n')
if err != nil {
log.Fatal(err)
}
versionString := strings.Split(firstLine, "protocol version ")

return versionString[1]
}

func (cmd *syncCmd) Run(fl *pflag.FlagSet) {
var (
local = fl.Arg(0)
Expand Down Expand Up @@ -71,6 +92,16 @@ func (cmd *syncCmd) Run(fl *pflag.FlagSet) {
LocalDir: absLocal,
Client: entClient,
}

localVersion := cmd.version()
remoteVersion, rsyncErr := s.Version()

if rsyncErr != nil {
flog.Info("Unable to determine remote rsync version. Proceeding cautiously.")
} else if localVersion != remoteVersion {
flog.Fatal(fmt.Sprintf("rsync protocol mismatch. %s.", localVersion, rsyncErr))
}

for err == nil || err == sync.ErrRestartSync {
err = s.Run()
}
Expand Down
40 changes: 40 additions & 0 deletions internal/sync/sync.go
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package sync

import (
"bytes"
"context"
"errors"
"fmt"
Expand All @@ -10,6 +11,7 @@ import (
"os/exec"
"path"
"path/filepath"
"strings"
"sync"
"sync/atomic"
"time"
Expand Down Expand Up @@ -261,6 +263,44 @@ const (
maxAcceptableDispatch = time.Millisecond * 50
)

// Version returns remote protocol version as a string.
// Or, an error if one exists.
func (s Sync) Version() (string, error) {
ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
defer cancel()

conn, err := s.Client.DialWsep(ctx, s.Env)
if err != nil {
return "", err
}
defer conn.Close(websocket.CloseNormalClosure, "")

execer := wsep.RemoteExecer(conn)
process, err := execer.Start(ctx, wsep.Command{
Command: "rsync",
Args: []string{"--version"},
})
if err != nil {
return "", err
}
buf := &bytes.Buffer{}
io.Copy(buf, process.Stdout())

err = process.Wait()
if err != nil {
return "", err
}

firstLine, err := buf.ReadString('\n')
if err != nil {
return "", err
}

versionString := strings.Split(firstLine, "protocol version ")

return versionString[1], nil
}

// Run starts the sync synchronously.
// Use this command to debug what wasn't sync'd correctly:
// rsync -e "coder sh" -nicr ~/Projects/cdr/coder-cli/. ammar:/home/coder/coder-cli/
Expand Down