/
dst.go
284 lines (226 loc) · 5.12 KB
/
dst.go
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package filetransfer
import (
"context"
"crypto/tls"
"io"
"log"
"os"
"path/filepath"
"time"
"github.com/pojntfx/networked-linux-memsync/pkg/utils"
)
// {
// wg.Add(1)
// go func() {
// if err := filetransfer.ReceiveFileLoop(
// ctx,
// *hashParallel,
// d,
// *syncerRaddr,
// func(src string) bool {
// for _, hv := range hypervisors {
// // Ignore local, running virtual machines to prevent sync loopback
// if !hv.computePaused && strings.HasPrefix(src, filepath.Join("/", vmDirName, hv.id)) {
// return false
// }
// }
// return true
// },
// func(src string) string {
// return filepath.Join(*firecrackerWorkdir, src)
// },
// *blocksize,
// func(src string) bool {
// if *rootfsWritable {
// return false
// }
// // Only sync rootfs once if its mounted read-only, as calculating hashes can be very slow
// return strings.HasSuffix(src, rootfsName)
// },
// *verbose,
// ); err != nil {
// panic(err)
// }
// }()
// }
type nopReader struct{}
func (r nopReader) Read(p []byte) (n int, err error) {
n = copy(p, make([]byte, len(p)))
return n, nil
}
func ReceiveFile(
parallel int64,
file *os.File,
path string,
blocksize int64,
conn io.ReadWriter,
verbose bool,
) error {
beforeHash := time.Now()
localHashes, _, err := GetHashesForBlocks(parallel, path, blocksize)
if err != nil {
return err
}
if verbose {
log.Printf("Calculated hashes for %v blocks in %v", len(localHashes), time.Since(beforeHash))
}
if err := utils.EncodeJSONFixedLength(conn, localHashes); err != nil {
return err
}
blocksToFetch := []int64{}
if err := utils.DecodeJSONFixedLength(conn, &blocksToFetch); err != nil {
return err
}
cutoff := int64(0)
if err := utils.DecodeJSONFixedLength(conn, &cutoff); err != nil {
return err
}
if cutoff == -1 {
if verbose {
log.Println("Truncating file")
}
if err := file.Truncate(0); err != nil {
return err
}
return nil
}
if verbose {
log.Printf("Fetching changed blocks %v with cutoff %v", blocksToFetch, cutoff)
}
beforeDownload := time.Now()
if len(blocksToFetch) > 0 {
s, err := os.Stat(path)
if err != nil {
return err
}
newSize := (((blocksToFetch[len(blocksToFetch)-1] + 1) * blocksize) - cutoff)
diff := s.Size() - newSize
if diff > 0 {
// If the file on the server got smaller, truncate the local file accordingly
if err := file.Truncate(newSize); err != nil {
return err
}
} else {
// If the file on the server grew, grow the local file accordingly
if _, err := file.Seek(0, 2); err != nil {
return err
}
if _, err := io.CopyN(file, nopReader{}, -diff); err != nil {
return err
}
}
}
n := int64(0)
for i, blockToFetch := range blocksToFetch {
backset := int64(0)
if i == len(blocksToFetch)-1 {
backset = cutoff
}
b := make([]byte, blocksize-backset)
if _, err := io.ReadFull(conn, b); err != nil {
return err
}
m, err := file.WriteAt(b, blockToFetch*(blocksize))
if err != nil {
return err
}
n += int64(m)
}
if verbose {
log.Printf("Received %v bytes in %v", n, time.Since(beforeDownload))
}
return nil
}
func ReceiveFileLoop(
ctx context.Context,
parallel int64,
d tls.Dialer,
syncerRaddr string,
getAccept func(src string) bool,
getDstPath func(src string) string,
blocksize int64,
once func(src string) bool,
verbose bool,
) error {
syncerConn, err := d.DialContext(ctx, "tcp", syncerRaddr)
if err != nil {
panic(err)
}
defer syncerConn.Close()
go func() {
<-ctx.Done()
_ = syncerConn.Close()
}()
if verbose {
log.Println("Sharer destination connected to syncer", syncerConn.RemoteAddr())
}
if err := utils.EncodeJSONFixedLength(syncerConn, "dst-control"); err != nil {
if utils.IsClosedErr(err) {
return nil
}
panic(err)
}
errs := make(chan error)
go func() {
for {
file := ""
if err := utils.DecodeJSONFixedLength(syncerConn, &file); err != nil {
if utils.IsClosedErr(err) {
errs <- nil
return
}
errs <- err
return
}
if !getAccept(file) {
continue
}
go func() {
dataConn, err := d.DialContext(ctx, "tcp", syncerRaddr)
if err != nil {
errs <- err
return
}
defer dataConn.Close()
dst := getDstPath(file)
if err := os.MkdirAll(filepath.Dir(dst), os.ModePerm); err != nil {
errs <- err
return
}
f, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE, os.ModePerm)
if err != nil {
errs <- err
return
}
defer f.Close()
if err := utils.EncodeJSONFixedLength(dataConn, "dst"); err != nil {
if utils.IsClosedErr(err) {
return
}
errs <- err
return
}
if err := utils.EncodeJSONFixedLength(dataConn, file); err != nil {
if utils.IsClosedErr(err) {
return
}
errs <- err
return
}
for {
if err := ReceiveFile(parallel, f, dst, blocksize, dataConn, verbose); err != nil {
if utils.IsClosedErr(err) {
return
}
errs <- err
return
}
if once(file) {
return
}
}
}()
}
}()
return <-errs
}