rclone/fs/operations/check.go
Nick Craig-Wood 4013bc4a4c Fix excessive retries missing --max-duration timeout - fixes #4504
This change checks the context whenever rclone might retry, and
doesn't retry if the current context has an error.

This fixes the pathological behaviour of `--max-duration` refusing to
exit because all the context deadline exceeded errors were being
retried.

This unfortunately meant changing the shouldRetry logic in every
backend and doing a lot of context propagation.

See: https://forum.rclone.org/t/add-flag-to-exit-immediately-when-max-duration-reached/22723
2021-03-13 09:25:44 +00:00

360 lines
10 KiB
Go

package operations
import (
"bytes"
"context"
"fmt"
"io"
"sync"
"sync/atomic"
"github.com/pkg/errors"
"github.com/rclone/rclone/fs"
"github.com/rclone/rclone/fs/accounting"
"github.com/rclone/rclone/fs/fserrors"
"github.com/rclone/rclone/fs/hash"
"github.com/rclone/rclone/fs/march"
"github.com/rclone/rclone/lib/readers"
)
// checkFn is the type of the checking function used in CheckFn()
//
// It should check the two objects (a, b) and return if they differ
// and whether the hash was used.
//
// If there are differences then this should Errorf the difference and
// the reason but return with err = nil. It should not CountError in
// this case.
type checkFn func(ctx context.Context, a, b fs.Object) (differ bool, noHash bool, err error)
// CheckOpt contains options for the Check functions
type CheckOpt struct {
Fdst, Fsrc fs.Fs // fses to check
Check checkFn // function to use for checking
OneWay bool // one way only?
Combined io.Writer // a file with file names with leading sigils
MissingOnSrc io.Writer // files only in the destination
MissingOnDst io.Writer // files only in the source
Match io.Writer // matching files
Differ io.Writer // differing files
Error io.Writer // files with errors of some kind
}
// checkMarch is used to march over two Fses in the same way as
// sync/copy
type checkMarch struct {
ioMu sync.Mutex
wg sync.WaitGroup
tokens chan struct{}
differences int32
noHashes int32
srcFilesMissing int32
dstFilesMissing int32
matches int32
opt CheckOpt
}
// report outputs the fileName to out if required and to the combined log
func (c *checkMarch) report(o fs.DirEntry, out io.Writer, sigil rune) {
if out != nil {
c.ioMu.Lock()
_, _ = fmt.Fprintf(out, "%v\n", o)
c.ioMu.Unlock()
}
if c.opt.Combined != nil {
c.ioMu.Lock()
_, _ = fmt.Fprintf(c.opt.Combined, "%c %v\n", sigil, o)
c.ioMu.Unlock()
}
}
// DstOnly have an object which is in the destination only
func (c *checkMarch) DstOnly(dst fs.DirEntry) (recurse bool) {
switch dst.(type) {
case fs.Object:
if c.opt.OneWay {
return false
}
err := errors.Errorf("File not in %v", c.opt.Fsrc)
fs.Errorf(dst, "%v", err)
_ = fs.CountError(err)
atomic.AddInt32(&c.differences, 1)
atomic.AddInt32(&c.srcFilesMissing, 1)
c.report(dst, c.opt.MissingOnSrc, '-')
case fs.Directory:
// Do the same thing to the entire contents of the directory
if c.opt.OneWay {
return false
}
return true
default:
panic("Bad object in DirEntries")
}
return false
}
// SrcOnly have an object which is in the source only
func (c *checkMarch) SrcOnly(src fs.DirEntry) (recurse bool) {
switch src.(type) {
case fs.Object:
err := errors.Errorf("File not in %v", c.opt.Fdst)
fs.Errorf(src, "%v", err)
_ = fs.CountError(err)
atomic.AddInt32(&c.differences, 1)
atomic.AddInt32(&c.dstFilesMissing, 1)
c.report(src, c.opt.MissingOnDst, '+')
case fs.Directory:
// Do the same thing to the entire contents of the directory
return true
default:
panic("Bad object in DirEntries")
}
return false
}
// check to see if two objects are identical using the check function
func (c *checkMarch) checkIdentical(ctx context.Context, dst, src fs.Object) (differ bool, noHash bool, err error) {
ci := fs.GetConfig(ctx)
tr := accounting.Stats(ctx).NewCheckingTransfer(src)
defer func() {
tr.Done(ctx, err)
}()
if sizeDiffers(ctx, src, dst) {
err = errors.Errorf("Sizes differ")
fs.Errorf(src, "%v", err)
return true, false, nil
}
if ci.SizeOnly {
return false, false, nil
}
return c.opt.Check(ctx, dst, src)
}
// Match is called when src and dst are present, so sync src to dst
func (c *checkMarch) Match(ctx context.Context, dst, src fs.DirEntry) (recurse bool) {
switch srcX := src.(type) {
case fs.Object:
dstX, ok := dst.(fs.Object)
if ok {
if SkipDestructive(ctx, src, "check") {
return false
}
c.wg.Add(1)
c.tokens <- struct{}{} // put a token to limit concurrency
go func() {
defer func() {
<-c.tokens // get the token back to free up a slot
c.wg.Done()
}()
differ, noHash, err := c.checkIdentical(ctx, dstX, srcX)
if err != nil {
fs.Errorf(src, "%v", err)
_ = fs.CountError(err)
c.report(src, c.opt.Error, '!')
} else if differ {
atomic.AddInt32(&c.differences, 1)
err := errors.New("files differ")
// the checkFn has already logged the reason
_ = fs.CountError(err)
c.report(src, c.opt.Differ, '*')
} else {
atomic.AddInt32(&c.matches, 1)
c.report(src, c.opt.Match, '=')
if noHash {
atomic.AddInt32(&c.noHashes, 1)
fs.Debugf(dstX, "OK - could not check hash")
} else {
fs.Debugf(dstX, "OK")
}
}
}()
} else {
err := errors.Errorf("is file on %v but directory on %v", c.opt.Fsrc, c.opt.Fdst)
fs.Errorf(src, "%v", err)
_ = fs.CountError(err)
atomic.AddInt32(&c.differences, 1)
atomic.AddInt32(&c.dstFilesMissing, 1)
c.report(src, c.opt.MissingOnDst, '+')
}
case fs.Directory:
// Do the same thing to the entire contents of the directory
_, ok := dst.(fs.Directory)
if ok {
return true
}
err := errors.Errorf("is file on %v but directory on %v", c.opt.Fdst, c.opt.Fsrc)
fs.Errorf(dst, "%v", err)
_ = fs.CountError(err)
atomic.AddInt32(&c.differences, 1)
atomic.AddInt32(&c.srcFilesMissing, 1)
c.report(dst, c.opt.MissingOnSrc, '-')
default:
panic("Bad object in DirEntries")
}
return false
}
// CheckFn checks the files in fsrc and fdst according to Size and
// hash using checkFunction on each file to check the hashes.
//
// checkFunction sees if dst and src are identical
//
// it returns true if differences were found
// it also returns whether it couldn't be hashed
func CheckFn(ctx context.Context, opt *CheckOpt) error {
ci := fs.GetConfig(ctx)
if opt.Check == nil {
return errors.New("internal error: nil check function")
}
c := &checkMarch{
tokens: make(chan struct{}, ci.Checkers),
opt: *opt,
}
// set up a march over fdst and fsrc
m := &march.March{
Ctx: ctx,
Fdst: c.opt.Fdst,
Fsrc: c.opt.Fsrc,
Dir: "",
Callback: c,
}
fs.Debugf(c.opt.Fdst, "Waiting for checks to finish")
err := m.Run(ctx)
c.wg.Wait() // wait for background go-routines
if c.dstFilesMissing > 0 {
fs.Logf(c.opt.Fdst, "%d files missing", c.dstFilesMissing)
}
if c.srcFilesMissing > 0 {
fs.Logf(c.opt.Fsrc, "%d files missing", c.srcFilesMissing)
}
fs.Logf(c.opt.Fdst, "%d differences found", accounting.Stats(ctx).GetErrors())
if errs := accounting.Stats(ctx).GetErrors(); errs > 0 {
fs.Logf(c.opt.Fdst, "%d errors while checking", errs)
}
if c.noHashes > 0 {
fs.Logf(c.opt.Fdst, "%d hashes could not be checked", c.noHashes)
}
if c.matches > 0 {
fs.Logf(c.opt.Fdst, "%d matching files", c.matches)
}
if err != nil {
return err
}
if c.differences > 0 {
// Return an already counted error so we don't double count this error too
err = fserrors.FsError(errors.Errorf("%d differences found", c.differences))
fserrors.Count(err)
return err
}
return nil
}
// Check the files in fsrc and fdst according to Size and hash
func Check(ctx context.Context, opt *CheckOpt) error {
optCopy := *opt
optCopy.Check = func(ctx context.Context, dst, src fs.Object) (differ bool, noHash bool, err error) {
same, ht, err := CheckHashes(ctx, src, dst)
if err != nil {
return true, false, err
}
if ht == hash.None {
return false, true, nil
}
if !same {
err = errors.Errorf("%v differ", ht)
fs.Errorf(src, "%v", err)
return true, false, nil
}
return false, false, nil
}
return CheckFn(ctx, &optCopy)
}
// CheckEqualReaders checks to see if in1 and in2 have the same
// content when read.
//
// it returns true if differences were found
func CheckEqualReaders(in1, in2 io.Reader) (differ bool, err error) {
const bufSize = 64 * 1024
buf1 := make([]byte, bufSize)
buf2 := make([]byte, bufSize)
for {
n1, err1 := readers.ReadFill(in1, buf1)
n2, err2 := readers.ReadFill(in2, buf2)
// check errors
if err1 != nil && err1 != io.EOF {
return true, err1
} else if err2 != nil && err2 != io.EOF {
return true, err2
}
// err1 && err2 are nil or io.EOF here
// process the data
if n1 != n2 || !bytes.Equal(buf1[:n1], buf2[:n2]) {
return true, nil
}
// if both streams finished the we have finished
if err1 == io.EOF && err2 == io.EOF {
break
}
}
return false, nil
}
// CheckIdenticalDownload checks to see if dst and src are identical
// by reading all their bytes if necessary.
//
// it returns true if differences were found
func CheckIdenticalDownload(ctx context.Context, dst, src fs.Object) (differ bool, err error) {
ci := fs.GetConfig(ctx)
err = Retry(ctx, src, ci.LowLevelRetries, func() error {
differ, err = checkIdenticalDownload(ctx, dst, src)
return err
})
return differ, err
}
// Does the work for CheckIdenticalDownload
func checkIdenticalDownload(ctx context.Context, dst, src fs.Object) (differ bool, err error) {
in1, err := dst.Open(ctx)
if err != nil {
return true, errors.Wrapf(err, "failed to open %q", dst)
}
tr1 := accounting.Stats(ctx).NewTransfer(dst)
defer func() {
tr1.Done(ctx, nil) // error handling is done by the caller
}()
in1 = tr1.Account(ctx, in1).WithBuffer() // account and buffer the transfer
in2, err := src.Open(ctx)
if err != nil {
return true, errors.Wrapf(err, "failed to open %q", src)
}
tr2 := accounting.Stats(ctx).NewTransfer(dst)
defer func() {
tr2.Done(ctx, nil) // error handling is done by the caller
}()
in2 = tr2.Account(ctx, in2).WithBuffer() // account and buffer the transfer
// To assign err variable before defer.
differ, err = CheckEqualReaders(in1, in2)
return
}
// CheckDownload checks the files in fsrc and fdst according to Size
// and the actual contents of the files.
func CheckDownload(ctx context.Context, opt *CheckOpt) error {
optCopy := *opt
optCopy.Check = func(ctx context.Context, a, b fs.Object) (differ bool, noHash bool, err error) {
differ, err = CheckIdenticalDownload(ctx, a, b)
if err != nil {
return true, true, errors.Wrap(err, "failed to download")
}
return differ, false, nil
}
return CheckFn(ctx, &optCopy)
}