rclone/fs/operations/check.go
Nick Craig-Wood 421585dd72 accounting: add context to Account and propagate changes #3257
This is preparation for getting the Accounting to check the context,
buf first we need to get it in place. Since this is one of those
changes that makes lots of noise, this is in a seperate commit.
2020-07-28 16:41:17 +01:00

350 lines
9.8 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/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) {
tr := accounting.Stats(ctx).NewCheckingTransfer(src)
defer func() {
tr.Done(err)
}()
if sizeDiffers(src, dst) {
err = errors.Errorf("Sizes differ")
fs.Errorf(src, "%v", err)
return true, false, nil
}
if fs.Config.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 {
if opt.Check == nil {
return errors.New("internal error: nil check function")
}
c := &checkMarch{
tokens: make(chan struct{}, fs.Config.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()
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 c.differences > 0 {
return errors.Errorf("%d differences found", c.differences)
}
return err
}
// 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) {
err = Retry(src, fs.Config.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(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(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)
}