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restic/internal/archiver/file_saver.go
2018-05-12 23:55:59 +02:00

251 lines
5.5 KiB
Go

package archiver
import (
"context"
"io"
"os"
"github.com/restic/chunker"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/fs"
"github.com/restic/restic/internal/restic"
tomb "gopkg.in/tomb.v2"
)
// FutureFile is returned by Save and will return the data once it
// has been processed.
type FutureFile struct {
ch <-chan saveFileResponse
res saveFileResponse
}
// Wait blocks until the result of the save operation is received or ctx is
// cancelled.
func (s *FutureFile) Wait(ctx context.Context) {
select {
case res, ok := <-s.ch:
if ok {
s.res = res
}
case <-ctx.Done():
return
}
}
// Node returns the node once it is available.
func (s *FutureFile) Node() *restic.Node {
return s.res.node
}
// Stats returns the stats for the file once they are available.
func (s *FutureFile) Stats() ItemStats {
return s.res.stats
}
// Err returns the error in case an error occurred.
func (s *FutureFile) Err() error {
return s.res.err
}
// SaveBlobFn saves a blob to a repo.
type SaveBlobFn func(context.Context, restic.BlobType, *Buffer) FutureBlob
// FileSaver concurrently saves incoming files to the repo.
type FileSaver struct {
fs fs.FS
saveFilePool *BufferPool
saveBlob SaveBlobFn
pol chunker.Pol
ch chan<- saveFileJob
done <-chan struct{}
CompleteBlob func(filename string, bytes uint64)
NodeFromFileInfo func(filename string, fi os.FileInfo) (*restic.Node, error)
}
// NewFileSaver returns a new file saver. A worker pool with fileWorkers is
// started, it is stopped when ctx is cancelled.
func NewFileSaver(ctx context.Context, t *tomb.Tomb, fs fs.FS, save SaveBlobFn, pol chunker.Pol, fileWorkers, blobWorkers uint) *FileSaver {
ch := make(chan saveFileJob)
debug.Log("new file saver with %v file workers and %v blob workers", fileWorkers, blobWorkers)
poolSize := fileWorkers + blobWorkers
s := &FileSaver{
fs: fs,
saveBlob: save,
saveFilePool: NewBufferPool(ctx, int(poolSize), chunker.MaxSize),
pol: pol,
ch: ch,
done: t.Dying(),
CompleteBlob: func(string, uint64) {},
}
for i := uint(0); i < fileWorkers; i++ {
t.Go(func() error {
s.worker(t.Context(ctx), ch)
return nil
})
}
return s
}
// CompleteFunc is called when the file has been saved.
type CompleteFunc func(*restic.Node, ItemStats)
// Save stores the file f and returns the data once it has been completed. The
// file is closed by Save.
func (s *FileSaver) Save(ctx context.Context, snPath string, file fs.File, fi os.FileInfo, start func(), complete CompleteFunc) FutureFile {
ch := make(chan saveFileResponse, 1)
job := saveFileJob{
snPath: snPath,
file: file,
fi: fi,
start: start,
complete: complete,
ch: ch,
}
select {
case s.ch <- job:
case <-s.done:
debug.Log("not sending job, FileSaver is done")
_ = file.Close()
close(ch)
return FutureFile{ch: ch}
case <-ctx.Done():
debug.Log("not sending job, context is cancelled: %v", ctx.Err())
_ = file.Close()
close(ch)
return FutureFile{ch: ch}
}
return FutureFile{ch: ch}
}
type saveFileJob struct {
snPath string
file fs.File
fi os.FileInfo
ch chan<- saveFileResponse
complete CompleteFunc
start func()
}
type saveFileResponse struct {
node *restic.Node
stats ItemStats
err error
}
// saveFile stores the file f in the repo, then closes it.
func (s *FileSaver) saveFile(ctx context.Context, chnker *chunker.Chunker, snPath string, f fs.File, fi os.FileInfo, start func()) saveFileResponse {
start()
stats := ItemStats{}
debug.Log("%v", snPath)
node, err := s.NodeFromFileInfo(f.Name(), fi)
if err != nil {
_ = f.Close()
return saveFileResponse{err: err}
}
if node.Type != "file" {
_ = f.Close()
return saveFileResponse{err: errors.Errorf("node type %q is wrong", node.Type)}
}
// reuse the chunker
chnker.Reset(f, s.pol)
var results []FutureBlob
node.Content = []restic.ID{}
var size uint64
for {
buf := s.saveFilePool.Get()
chunk, err := chnker.Next(buf.Data)
if errors.Cause(err) == io.EOF {
buf.Release()
break
}
buf.Data = chunk.Data
size += uint64(chunk.Length)
if err != nil {
_ = f.Close()
return saveFileResponse{err: err}
}
// test if the context has been cancelled, return the error
if ctx.Err() != nil {
_ = f.Close()
return saveFileResponse{err: ctx.Err()}
}
res := s.saveBlob(ctx, restic.DataBlob, buf)
results = append(results, res)
// test if the context has been cancelled, return the error
if ctx.Err() != nil {
_ = f.Close()
return saveFileResponse{err: ctx.Err()}
}
s.CompleteBlob(f.Name(), uint64(len(chunk.Data)))
}
err = f.Close()
if err != nil {
return saveFileResponse{err: err}
}
for _, res := range results {
res.Wait(ctx)
if !res.Known() {
stats.DataBlobs++
stats.DataSize += uint64(res.Length())
}
node.Content = append(node.Content, res.ID())
}
node.Size = size
return saveFileResponse{
node: node,
stats: stats,
}
}
func (s *FileSaver) worker(ctx context.Context, jobs <-chan saveFileJob) {
// a worker has one chunker which is reused for each file (because it contains a rather large buffer)
chnker := chunker.New(nil, s.pol)
for {
var job saveFileJob
select {
case <-ctx.Done():
return
case job = <-jobs:
}
res := s.saveFile(ctx, chnker, job.snPath, job.file, job.fi, job.start)
if job.complete != nil {
job.complete(res.node, res.stats)
}
job.ch <- res
close(job.ch)
}
}