initial commit

This commit is contained in:
ston1th 2022-03-13 18:49:27 +01:00
commit 3053f89410
39 changed files with 4567 additions and 0 deletions

52
pkg/fs/chunk.go Normal file
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// Copyright (C) 2022 Marius Schellenberger
package fs
import "sort"
type Chunk [2]int64
type Chunks []Chunk
func (cs Chunks) Len() int { return len(cs) }
func (cs Chunks) Less(i, j int) bool { return cs[i][0] < cs[j][0] }
func (cs Chunks) Swap(i, j int) { cs[i], cs[j] = cs[j], cs[i] }
func (cs Chunks) Exists(off int64, n int, size int64) bool {
end := off + int64(n)
if end > size {
end = size
}
for _, c := range cs {
if c[0] <= off && c[1] > off && c[1] >= end {
return true
}
}
return false
}
func (cs *Chunks) Add(off int64, n int) {
*cs = append(*cs, Chunk{off, off + int64(n)})
cs.merge()
}
func (cs *Chunks) merge() {
c := *cs
if len(c) < 2 {
return
}
sort.Sort(*cs)
for i := 0; i < len(c); i++ {
if i+1 == len(c) {
break
}
if c[i][1] >= c[i+1][0] {
if c[i+1][1] > c[i][1] {
c[i][1] = c[i+1][1]
}
c = append(c[:i+1], c[i+2:]...)
i--
}
}
*cs = c
}

106
pkg/fs/file.go Normal file
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// Copyright (C) 2022 Marius Schellenberger
package fs
import (
"io"
"os"
"github.com/go-logr/logr"
)
type File struct {
log logr.Logger
f *os.File
md *Metadata
offset int64
}
type preload struct {
f *File
skipped int64
written int64
}
func (p *preload) Read(data []byte) (n int, err error) {
if p.f.offset >= p.f.size() {
return 0, io.EOF
}
n = len(data)
if p.f.hasChunk(n) {
p.skipped++
_, err = p.f.Seek(int64(n), io.SeekCurrent)
return
}
n, err = p.f.readWithoutCache(data)
p.written++
return
}
func (f *File) Preload(unlock func()) {
f.log.V(2).Info("preload started")
p := &preload{f: f}
_, err := io.Copy(io.Discard, p)
if err != nil && err != io.EOF {
f.log.Error(err, "error preloading file")
}
f.log.V(2).Info("preload finished", "skipped", p.skipped, "written", p.written)
unlock()
}
func (f *File) Read(p []byte) (n int, err error) {
if f.hasChunk(len(p)) {
n, err = f.md.ReadAt(p, f.offset)
if err != nil {
return
}
_, err = f.Seek(int64(n), io.SeekCurrent)
return
}
return f.readWithoutCache(p)
}
func (f *File) size() int64 {
return f.md.Size
}
func (f *File) hasChunk(n int) bool {
return f.md.HasChunk(f.offset, n)
}
func (f *File) readWithoutCache(p []byte) (n int, err error) {
n, err = f.f.Read(p)
if err != nil {
return
}
f.md.WriteAt(p, f.offset)
f.md.AddChunk(f.offset, n)
f.offset += int64(n)
return
}
func (f *File) Seek(offset int64, whence int) (n int64, err error) {
n, err = f.f.Seek(offset, whence)
if err != nil {
return
}
switch whence {
case io.SeekStart:
f.offset = offset
case io.SeekCurrent:
f.offset += offset
}
return
}
func (f *File) Readdir(count int) ([]os.FileInfo, error) {
return f.f.Readdir(count)
}
func (f *File) Stat() (os.FileInfo, error) {
return f.f.Stat()
}
func (f *File) Close() error {
return f.f.Close()
}

225
pkg/fs/fs.go Normal file
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// Copyright (C) 2022 Marius Schellenberger
package fs
import (
"context"
"encoding/json"
"errors"
"io"
stdfs "io/fs"
"net/http"
"os"
"path"
"path/filepath"
"strings"
"sync"
"time"
"github.com/go-logr/logr"
)
type FS struct {
mu sync.RWMutex
log logr.Logger
NoCache http.Handler
src string
dst string
mdf *os.File
jenc *json.Encoder
mm map[string]*Metadata
cancel func()
}
func NewFS(src, dst, metadata string, log logr.Logger) (fs *FS, err error) {
if !filepath.IsAbs(src) {
return nil, errors.New("src path is not absolute")
}
if !filepath.IsAbs(dst) {
return nil, errors.New("dst path is not absolute")
}
if !filepath.IsAbs(metadata) {
return nil, errors.New("metadata path is not absolute")
}
if src == dst {
return nil, errors.New("src and dst path can not be equal")
}
mdf, err := os.OpenFile(metadata, os.O_RDWR|os.O_CREATE, 0o640)
if err != nil {
return
}
fs = &FS{
log: log,
NoCache: http.FileServer(http.Dir(src)),
src: src,
dst: dst,
mdf: mdf,
mm: make(map[string]*Metadata),
jenc: json.NewEncoder(mdf),
}
err = json.NewDecoder(mdf).Decode(&fs.mm)
if err == io.EOF {
err = nil
}
for k := range fs.mm {
_, err = stat(fs.dst, k)
if errors.Is(err, os.ErrNotExist) {
delete(fs.mm, k)
}
}
ctx, cancel := context.WithCancel(context.Background())
fs.cancel = cancel
go fs.flusher(ctx)
return fs, err
}
func (fs *FS) Stat(name string) (stdfs.FileInfo, error) {
return stat(fs.src, name)
}
func (fs *FS) Open(name string) (http.File, error) {
return fs.open(name)
}
func (fs *FS) Preload(name string) {
f, err := fs.open(name)
if err != nil {
return
}
if f.md.Preload() {
fs.log.WithValues("file", name).Error(errors.New("preload is running"), "error starting preload")
return
}
unlock := func() { f.md.UnlockPreload() }
go f.Preload(unlock)
}
func skipLog(name string) bool {
return strings.HasSuffix(name, "index.html")
}
func (fs *FS) open(name string) (f *File, err error) {
log := fs.log.WithValues("file", name)
rp := filepath.Join(fs.src, filepath.FromSlash(path.Clean("/"+name)))
rf, err := os.Open(rp)
if err != nil {
if !skipLog(name) {
log.Error(err, "error opening source file")
}
return
}
rfi, err := rf.Stat()
if err != nil {
log.Error(err, "error stat source file")
return
}
if rfi.IsDir() {
return &File{f: rf}, nil
}
mp := filepath.Join(fs.dst, filepath.FromSlash(path.Clean("/"+name)))
var mf *os.File
i := strings.LastIndex(mp, "/")
if i > 0 {
dir := mp[:i]
_, err = os.Stat(dir)
if errors.Is(err, os.ErrNotExist) {
err = os.MkdirAll(dir, 0o755)
if err != nil {
log.Error(err, "error creating cache dir", "dir", mp)
return nil, err
}
}
}
_, err = os.Stat(mp)
truncate := errors.Is(err, os.ErrNotExist)
if !fs.isOpen(name) {
mf, err = os.OpenFile(mp, os.O_RDWR|os.O_CREATE, 0o644)
if err != nil {
log.Error(err, "error opening cache file")
return nil, err
}
if truncate {
err = mf.Truncate(rfi.Size())
if err != nil {
log.Error(err, "error truncating cache file")
return nil, err
}
err = mf.Sync()
if err != nil {
log.Error(err, "error syncing cache file")
return nil, err
}
}
}
return &File{
log: log,
f: rf,
md: fs.metadata(name, rfi.Size(), mf),
}, nil
}
func (fs *FS) isOpen(name string) bool {
fs.mu.RLock()
defer fs.mu.RUnlock()
md, ok := fs.mm[name]
return ok && md.f != nil
}
func (fs *FS) metadata(name string, size int64, f *os.File) (md *Metadata) {
fs.mu.Lock()
defer fs.mu.Unlock()
if md, ok := fs.mm[name]; ok {
if md.f == nil {
md.f = f
}
return md
}
md = &Metadata{Size: size, f: f}
fs.mm[name] = md
return
}
func (fs *FS) flusher(ctx context.Context) {
for {
select {
case <-ctx.Done():
return
case <-time.After(time.Minute * 5):
}
fs.flushMetadata()
}
}
func (fs *FS) flushMetadata() {
log := fs.log
fs.mu.Lock()
defer fs.mu.Unlock()
_, err := fs.mdf.Seek(0, io.SeekStart)
if err != nil {
log.Error(err, "failure seeking metadata file")
return
}
err = fs.mdf.Truncate(0)
if err != nil {
log.Error(err, "failure truncating metadata file")
return
}
err = fs.jenc.Encode(fs.mm)
if err != nil {
log.Error(err, "failure flushing metadata file")
}
}
func (fs *FS) Close() {
fs.cancel()
for _, md := range fs.mm {
md.f.Sync()
md.f.Close()
}
fs.flushMetadata()
}
func stat(prefix, name string) (stdfs.FileInfo, error) {
p := filepath.Join(prefix, filepath.FromSlash(path.Clean("/"+name)))
return os.Stat(p)
}

52
pkg/fs/metadata.go Normal file
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// Copyright (C) 2022 Marius Schellenberger
package fs
import (
"os"
"sync"
)
type Metadata struct {
mu sync.RWMutex `json:"-"`
f *os.File `json:"-"`
Size int64 `json:"s"`
Chunks Chunks `json:"c"`
preload bool `json:"-"`
}
func (md *Metadata) HasChunk(off int64, n int) bool {
md.mu.RLock()
defer md.mu.RUnlock()
return md.Chunks.Exists(off, n, md.Size)
}
func (md *Metadata) AddChunk(off int64, n int) {
md.mu.Lock()
defer md.mu.Unlock()
md.Chunks.Add(off, n)
}
func (md *Metadata) ReadAt(p []byte, pos int64) (int, error) {
return md.f.ReadAt(p, pos)
}
func (md *Metadata) WriteAt(data []byte, pos int64) (int, error) {
return md.f.WriteAt(data, pos)
}
func (md *Metadata) Preload() bool {
md.mu.Lock()
defer md.mu.Unlock()
if md.preload {
return true
}
md.preload = true
return false
}
func (md *Metadata) UnlockPreload() {
md.mu.Lock()
defer md.mu.Unlock()
md.preload = false
}