VictoriaMetrics/lib/backup/common/part.go
2019-11-12 00:16:42 +02:00

137 lines
3.2 KiB
Go

package common
import (
"fmt"
"regexp"
"sort"
"strconv"
"strings"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
)
// Part is an atomic unit for transfer during backup / restore.
//
// Each source file can be split into parts with up to MaxPartSize sizes.
type Part struct {
// Path is the path to file for backup.
Path string
// FileSize is the size of the whole file for the given part.
FileSize uint64
// Offset is offset in the file to backup.
Offset uint64
// Size is the size of the part to backup starting from Offset.
Size uint64
// ActualSize is the actual size of the part.
//
// The part is considered broken if it isn't equal to Size.
// Such a part must be removed from remote storage.
ActualSize uint64
}
func (p *Part) key() string {
return fmt.Sprintf("%s%016X%016X%016X%016X", p.Path, p.FileSize, p.Offset, p.Size, p.ActualSize)
}
// String returns human-readable representation of the part.
func (p *Part) String() string {
return fmt.Sprintf("part{path: %q, file_size: %d, offset: %d, size: %d}", p.Path, p.FileSize, p.Offset, p.Size)
}
// RemotePath returns remote path for the part p and the given prefix.
func (p *Part) RemotePath(prefix string) string {
for strings.HasSuffix(prefix, "/") {
prefix = prefix[:len(prefix)-1]
}
return fmt.Sprintf("%s/%s/%016X_%016X_%016X", prefix, p.Path, p.FileSize, p.Offset, p.Size)
}
var partNameRegexp = regexp.MustCompile(`^(.+)/([0-9A-F]{16})_([0-9A-F]{16})_([0-9A-F]{16})$`)
// ParseFromRemotePath parses p from remotePath.
//
// Returns true on success.
func (p *Part) ParseFromRemotePath(remotePath string) bool {
tmp := partNameRegexp.FindStringSubmatch(remotePath)
if len(tmp) != 5 {
return false
}
path := tmp[1]
for strings.HasPrefix(path, "/") {
path = path[1:]
}
fileSize, err := strconv.ParseUint(tmp[2], 16, 64)
if err != nil {
logger.Panicf("BUG: cannot parse fileSize from %q: %s", tmp[2], err)
}
offset, err := strconv.ParseUint(tmp[3], 16, 64)
if err != nil {
logger.Panicf("BUG: cannot parse offset from %q: %s", tmp[3], err)
}
size, err := strconv.ParseUint(tmp[4], 16, 64)
if err != nil {
logger.Panicf("BUG: cannot parse size from %q: %s", tmp[4], err)
}
p.Path = path
p.FileSize = fileSize
p.Offset = offset
p.Size = size
return true
}
// MaxPartSize is the maximum size for each part.
//
// The MaxPartSize reduces bandwidth usage during retires on network errors
// when transferring multi-TB files.
const MaxPartSize = 128 * 1024 * 1024
// SortParts sorts parts by (Path, Offset)
func SortParts(parts []Part) {
sort.Slice(parts, func(i, j int) bool {
a := parts[i]
b := parts[j]
if a.Path != b.Path {
return a.Path < b.Path
}
return a.Offset < b.Offset
})
}
// PartsDifference returns a - b
func PartsDifference(a, b []Part) []Part {
m := make(map[string]bool, len(b))
for _, p := range b {
k := p.key()
m[k] = true
}
var d []Part
for _, p := range a {
k := p.key()
if !m[k] {
d = append(d, p)
}
}
return d
}
// PartsIntersect returns the intersection of a and b
func PartsIntersect(a, b []Part) []Part {
m := make(map[string]bool, len(a))
for _, p := range a {
k := p.key()
m[k] = true
}
var d []Part
for _, p := range b {
k := p.key()
if m[k] {
d = append(d, p)
}
}
return d
}