tstor/src/sources/torrent/fs.go
royalcat 0371af3344
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file controller
2024-07-09 00:19:04 +03:00

557 lines
12 KiB
Go

package torrent
import (
"context"
"fmt"
"io"
"io/fs"
"log/slog"
"path"
"slices"
"strings"
"sync"
"sync/atomic"
"time"
"git.kmsign.ru/royalcat/tstor/pkg/rlog"
"git.kmsign.ru/royalcat/tstor/src/vfs"
"github.com/anacrolix/torrent"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/trace"
"golang.org/x/exp/maps"
)
type TorrentFS struct {
name string
Torrent *Controller
filesCacheMu sync.Mutex
filesCache map[string]vfs.File
lastTorrentReadTimeout atomic.Pointer[time.Time]
resolver *vfs.Resolver
}
var _ vfs.Filesystem = (*TorrentFS)(nil)
const shortTimeout = time.Millisecond
const lowTimeout = time.Second * 5
func (s *Daemon) NewTorrentFs(ctx context.Context, f vfs.File) (vfs.Filesystem, error) {
c, err := s.loadTorrent(ctx, f)
if err != nil {
return nil, err
}
if err := f.Close(ctx); err != nil {
s.log.Error(ctx, "failed to close file", slog.String("name", f.Name()), rlog.Error(err))
}
return &TorrentFS{
name: f.Name(),
Torrent: c,
resolver: vfs.NewResolver(vfs.ArchiveFactories),
}, nil
}
var _ fs.DirEntry = (*TorrentFS)(nil)
// Name implements fs.DirEntry.
func (tfs *TorrentFS) Name() string {
return tfs.name
}
// Info implements fs.DirEntry.
func (tfs *TorrentFS) Info() (fs.FileInfo, error) {
return tfs, nil
}
// IsDir implements fs.DirEntry.
func (tfs *TorrentFS) IsDir() bool {
return true
}
// Type implements fs.DirEntry.
func (tfs *TorrentFS) Type() fs.FileMode {
return fs.ModeDir
}
// ModTime implements fs.FileInfo.
func (tfs *TorrentFS) ModTime() time.Time {
return time.Time{}
}
// Mode implements fs.FileInfo.
func (tfs *TorrentFS) Mode() fs.FileMode {
return fs.ModeDir
}
// Size implements fs.FileInfo.
func (tfs *TorrentFS) Size() int64 {
return 0
}
// Sys implements fs.FileInfo.
func (tfs *TorrentFS) Sys() any {
return nil
}
// FsName implements Filesystem.
func (tfs *TorrentFS) FsName() string {
return "torrentfs"
}
func (fs *TorrentFS) files(ctx context.Context) (map[string]vfs.File, error) {
fs.filesCacheMu.Lock()
defer fs.filesCacheMu.Unlock()
if fs.filesCache != nil {
return fs.filesCache, nil
}
ctx, span := tracer.Start(ctx, "files", fs.traceAttrs())
defer span.End()
files, err := fs.Torrent.Files(ctx)
if err != nil {
return nil, err
}
fs.filesCache = make(map[string]vfs.File)
for _, file := range files {
props, err := file.Properties(ctx)
if err != nil {
return nil, err
}
if props.Excluded {
continue
}
p := vfs.AbsPath(file.Path())
tf, err := openTorrentFile(ctx, path.Base(p), file.file, &fs.lastTorrentReadTimeout)
if err != nil {
return nil, err
}
fs.filesCache[p] = tf
}
// TODO optional
if len(fs.filesCache) == 1 && fs.resolver.IsNestedFs(fs.Torrent.Name()) {
filepath := "/" + fs.Torrent.Name()
if file, ok := fs.filesCache[filepath]; ok {
nestedFs, err := fs.resolver.NestedFs(ctx, filepath, file)
if err != nil {
return nil, err
}
if nestedFs == nil {
goto DEFAULT_DIR // FIXME
}
fs.filesCache, err = listFilesRecursive(ctx, nestedFs, "/")
if err != nil {
return nil, err
}
return fs.filesCache, nil
}
}
DEFAULT_DIR:
rootDir := "/" + fs.Torrent.Name() + "/"
singleDir := true
for k, _ := range fs.filesCache {
if !strings.HasPrefix(k, rootDir) {
singleDir = false
}
}
if singleDir {
for k, f := range fs.filesCache {
delete(fs.filesCache, k)
k, _ = strings.CutPrefix(k, rootDir)
k = vfs.AbsPath(k)
fs.filesCache[k] = f
}
}
return fs.filesCache, nil
}
func listFilesRecursive(ctx context.Context, fs vfs.Filesystem, start string) (map[string]vfs.File, error) {
out := make(map[string]vfs.File, 0)
entries, err := fs.ReadDir(ctx, start)
if err != nil {
return nil, err
}
for _, entry := range entries {
filename := path.Join(start, entry.Name())
if entry.IsDir() {
rec, err := listFilesRecursive(ctx, fs, filename)
if err != nil {
return nil, err
}
maps.Copy(out, rec)
} else {
file, err := fs.Open(ctx, filename)
if err != nil {
return nil, err
}
out[filename] = file
}
}
return out, nil
}
func (fs *TorrentFS) rawOpen(ctx context.Context, filename string) (file vfs.File, err error) {
ctx, span := tracer.Start(ctx, "rawOpen",
fs.traceAttrs(attribute.String("filename", filename)),
)
defer func() {
if err != nil {
span.RecordError(err)
}
span.End()
}()
files, err := fs.files(ctx)
if err != nil {
return nil, err
}
file, err = vfs.GetFile(files, filename)
return file, err
}
func (fs *TorrentFS) rawStat(ctx context.Context, filename string) (fs.FileInfo, error) {
ctx, span := tracer.Start(ctx, "rawStat",
fs.traceAttrs(attribute.String("filename", filename)),
)
defer span.End()
files, err := fs.files(ctx)
if err != nil {
return nil, err
}
file, err := vfs.GetFile(files, filename)
if err != nil {
return nil, err
}
return file.Info()
}
func (fs *TorrentFS) traceAttrs(add ...attribute.KeyValue) trace.SpanStartOption {
return trace.WithAttributes(append([]attribute.KeyValue{
attribute.String("fs", fs.FsName()),
attribute.String("torrent", fs.Torrent.Name()),
attribute.String("infohash", fs.Torrent.InfoHash()),
}, add...)...)
}
func (tfs *TorrentFS) readContext(ctx context.Context) (context.Context, context.CancelFunc) {
lastReadTimeout := tfs.lastTorrentReadTimeout.Load()
if lastReadTimeout != nil && time.Since(*lastReadTimeout) < secondaryTimeout { // make short timeout for already faliled files
trace.SpanFromContext(ctx).SetAttributes(attribute.Bool("short_timeout", true))
return context.WithTimeout(ctx, shortTimeout)
}
return ctx, func() {}
}
// Stat implements Filesystem.
func (tfs *TorrentFS) Stat(ctx context.Context, filename string) (fs.FileInfo, error) {
ctx, span := tracer.Start(ctx, "Stat",
tfs.traceAttrs(attribute.String("filename", filename)),
)
defer span.End()
if vfs.IsRoot(filename) {
return tfs, nil
}
var err error
ctx, cancel := tfs.readContext(ctx)
defer func() {
cancel()
if err == context.DeadlineExceeded {
now := time.Now()
tfs.lastTorrentReadTimeout.Store(&now)
}
}()
fsPath, nestedFs, nestedFsPath, err := tfs.resolver.ResolvePath(ctx, filename, tfs.rawOpen)
if err != nil {
return nil, err
}
if nestedFs != nil {
return nestedFs.Stat(ctx, nestedFsPath)
}
return tfs.rawStat(ctx, fsPath)
}
func (tfs *TorrentFS) Open(ctx context.Context, filename string) (file vfs.File, err error) {
ctx, span := tracer.Start(ctx, "Open",
tfs.traceAttrs(attribute.String("filename", filename)),
)
defer span.End()
if vfs.IsRoot(filename) {
return vfs.NewDirFile(tfs.name), nil
}
ctx, cancel := tfs.readContext(ctx)
defer func() {
cancel()
if err == context.DeadlineExceeded {
now := time.Now()
tfs.lastTorrentReadTimeout.Store(&now)
}
}()
fsPath, nestedFs, nestedFsPath, err := tfs.resolver.ResolvePath(ctx, filename, tfs.rawOpen)
if err != nil {
return nil, err
}
if nestedFs != nil {
return nestedFs.Open(ctx, nestedFsPath)
}
return tfs.rawOpen(ctx, fsPath)
}
func (tfs *TorrentFS) ReadDir(ctx context.Context, name string) ([]fs.DirEntry, error) {
ctx, span := tracer.Start(ctx, "ReadDir",
tfs.traceAttrs(attribute.String("name", name)),
)
defer span.End()
var err error
ctx, cancel := tfs.readContext(ctx)
defer func() {
cancel()
if err == context.DeadlineExceeded {
now := time.Now()
tfs.lastTorrentReadTimeout.Store(&now)
}
}()
fsPath, nestedFs, nestedFsPath, err := tfs.resolver.ResolvePath(ctx, name, tfs.rawOpen)
if err != nil {
return nil, err
}
if nestedFs != nil {
return nestedFs.ReadDir(ctx, nestedFsPath)
}
files, err := tfs.files(ctx)
if err != nil {
return nil, err
}
return vfs.ListDirFromFiles(files, fsPath)
}
func (fs *TorrentFS) Unlink(ctx context.Context, name string) error {
ctx, span := tracer.Start(ctx, "Unlink",
fs.traceAttrs(attribute.String("name", name)),
)
defer span.End()
name = vfs.AbsPath(name)
files, err := fs.files(ctx)
if err != nil {
return err
}
if !slices.Contains(maps.Keys(files), name) {
return vfs.ErrNotExist
}
file := files[name]
fs.filesCacheMu.Lock()
delete(fs.filesCache, name)
fs.filesCacheMu.Unlock()
tfile, ok := file.(*torrentFile)
if !ok {
return vfs.ErrNotImplemented
}
return fs.Torrent.ExcludeFile(ctx, tfile.file)
}
var _ vfs.File = (*torrentFile)(nil)
type torrentFile struct {
name string
mu sync.RWMutex
tr torrent.Reader
lastReadTimeout atomic.Pointer[time.Time]
lastTorrentReadTimeout *atomic.Pointer[time.Time]
file *torrent.File
}
const secondaryTimeout = time.Hour * 24
func openTorrentFile(ctx context.Context, name string, file *torrent.File, lastTorrentReadTimeout *atomic.Pointer[time.Time]) (*torrentFile, error) {
select {
case <-file.Torrent().GotInfo():
break
case <-ctx.Done():
return nil, ctx.Err()
}
r := file.NewReader()
r.SetReadahead(1024 * 1024 * 16) // TODO configurable
_, err := r.ReadContext(ctx, make([]byte, 128))
if err != nil && err != io.EOF {
return nil, fmt.Errorf("failed initial file read: %w", err)
}
_, err = r.Seek(0, io.SeekStart)
if err != nil {
return nil, fmt.Errorf("failed seeking to start, after initial read: %w", err)
}
return &torrentFile{
name: name,
tr: r,
file: file,
lastTorrentReadTimeout: lastTorrentReadTimeout,
}, nil
}
// Name implements File.
func (tf *torrentFile) Name() string {
return tf.name
}
// Type implements File.
func (tf *torrentFile) Type() fs.FileMode {
return vfs.ROMode | fs.ModeDir
}
func (tf *torrentFile) Info() (fs.FileInfo, error) {
return vfs.NewFileInfo(tf.name, tf.file.Length()), nil
}
func (tf *torrentFile) Size() int64 {
return tf.file.Length()
}
func (tf *torrentFile) IsDir() bool {
return false
}
func (rw *torrentFile) Close(ctx context.Context) error {
rw.mu.Lock()
defer rw.mu.Unlock()
return rw.tr.Close()
}
func (tf *torrentFile) readTimeout(ctx context.Context) (context.Context, context.CancelFunc) {
lastReadTimeout := tf.lastReadTimeout.Load()
if lastReadTimeout != nil && time.Since(*lastReadTimeout) < secondaryTimeout { // make short timeout for already faliled files
trace.SpanFromContext(ctx).SetAttributes(attribute.Bool("short_timeout", true))
return context.WithTimeout(ctx, shortTimeout)
}
lastTorrentReadTimeout := tf.lastTorrentReadTimeout.Load()
if lastTorrentReadTimeout != nil && time.Since(*lastTorrentReadTimeout) < secondaryTimeout { // make short timeout for already faliled files
trace.SpanFromContext(ctx).SetAttributes(attribute.Bool("low_timeout", true))
return context.WithTimeout(ctx, lowTimeout)
}
return ctx, func() {}
}
// Read implements ctxio.Reader.
func (tf *torrentFile) Read(ctx context.Context, p []byte) (n int, err error) {
ctx, span := tracer.Start(ctx, "Read",
trace.WithAttributes(attribute.Int("length", len(p))),
)
defer func() {
span.SetAttributes(attribute.Int("read", n))
span.End()
}()
tf.mu.RLock()
defer tf.mu.RUnlock()
ctx, cancel := tf.readTimeout(ctx)
defer cancel()
defer func() {
if err == context.DeadlineExceeded {
now := time.Now()
tf.lastReadTimeout.Store(&now)
tf.lastTorrentReadTimeout.Store(&now)
}
}()
return tf.tr.ReadContext(ctx, p)
}
func (tf *torrentFile) ReadAt(ctx context.Context, p []byte, off int64) (n int, err error) {
ctx, span := tracer.Start(ctx, "ReadAt",
trace.WithAttributes(attribute.Int("length", len(p)), attribute.Int64("offset", off)),
)
defer func() {
span.SetAttributes(attribute.Int("read", n))
span.End()
}()
tf.mu.RLock()
defer tf.mu.RUnlock()
ctx, cancel := tf.readTimeout(ctx)
defer cancel()
defer func() {
if err == context.DeadlineExceeded {
now := time.Now()
tf.lastReadTimeout.Store(&now)
tf.lastTorrentReadTimeout.Store(&now)
}
}()
_, err = tf.tr.Seek(off, io.SeekStart)
if err != nil {
return 0, err
}
// return tf.tr.ReadContext(ctx, p)
n, err = readAtLeast(ctx, tf.tr, p, len(p))
_, err = tf.tr.Seek(0, io.SeekStart)
if err != nil {
return 0, err
}
return n, err
}
func readAtLeast(ctx context.Context, r torrent.Reader, buf []byte, min int) (n int, err error) {
if len(buf) < min {
return 0, io.ErrShortBuffer
}
for n < min && err == nil {
var nn int
nn, err = r.ReadContext(ctx, buf[n:])
n += nn
}
if n >= min {
err = nil
} else if n > 0 && err == io.EOF {
err = io.ErrUnexpectedEOF
}
return
}