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|
/*
Manage a deduplicated versionned backups repository.
Sample repository:
```
repo/
├── 00000/
│ ├── chunks/
│ │ ├── 000000000000000
│ │ ├── 000000000000001
│ │ ├── 000000000000002
│ │ ├── 000000000000003
│ ├── dentries
│ └── recipe
└── 00001/
├── chunks/
│ ├── 000000000000000
│ ├── 000000000000001
├── dentries
└── recipe
```
*/
package main
import (
"fmt"
"io"
"io/fs"
"io/ioutil"
"log"
"os"
"path"
"path/filepath"
"strconv"
)
const (
chunkSize = 8 << 10
)
type File struct {
Path string
Size int64
}
func Commit(source string, repo string) {
latest := GetLastVersion(repo)
new := latest + 1
newPath := path.Join(repo, fmt.Sprintf("%05d", new))
newChunkPath := path.Join(newPath, "chunks")
os.Mkdir(newPath, 0775)
os.Mkdir(newChunkPath, 0775)
files := make(chan File)
newChunks := make(chan []byte)
oldChunks := make(chan []byte)
go LoadChunks(repo, oldChunks)
go ListFiles(source, files)
go ReadFiles(files, newChunks)
StoreChunks(newChunkPath, newChunks)
}
func GetLastVersion(repo string) int {
v := -1
files, err := ioutil.ReadDir(repo)
if err != nil {
log.Fatalln(err)
}
for _, f := range files {
if !f.IsDir() {
continue
}
num, err := strconv.Atoi(f.Name())
if err != nil {
log.Println(err)
continue
}
if num > v {
v = num
}
}
return v
}
func ListFiles(path string, files chan<- File) {
err := filepath.Walk(path,
func(p string, i fs.FileInfo, err error) error {
if err != nil {
log.Println(err)
return err
}
if i.IsDir() {
return nil
}
var file = File{p, i.Size()}
files <- file
return nil
})
if err != nil {
log.Println(err)
}
close(files)
}
func ReadFiles(files <-chan File, chunks chan<- []byte) {
var buff []byte
var prev, read = chunkSize, 0
for f := range files {
file, err := os.Open(f.Path)
if err != nil {
log.Println(err)
continue
}
for err != io.EOF {
if prev == chunkSize {
buff = make([]byte, chunkSize)
prev, err = file.Read(buff)
} else {
read, err = file.Read(buff[prev:])
prev += read
}
if err != nil && err != io.EOF {
log.Println(err)
}
if prev == chunkSize {
chunks <- buff
}
}
}
chunks <- buff
close(chunks)
}
func PrintChunks(chunks <-chan []byte) {
for c := range chunks {
fmt.Println(c)
}
}
func StoreChunks(dest string, chunks <-chan []byte) {
i := 0
for c := range chunks {
path := path.Join(dest, fmt.Sprintf("%015d", i))
os.WriteFile(path, c, 0664)
i++
}
}
func LoadChunks(repo string, chunks chan<- []byte) {
err := filepath.WalkDir(repo,
func(p string, e fs.DirEntry, err error) error {
if err != nil {
log.Println(err)
return err
}
if e.IsDir() {
return nil
}
buff, err := os.ReadFile(p)
chunks <- buff
return nil
})
if err != nil {
log.Println(err)
}
close(chunks)
}
|
