etcd/tools/etcd-dump-db/scan.go
Benjamin Wang cb2f7b7a63 Support scan-keys command to scan the key space starting a specific revision
Signed-off-by: Benjamin Wang <benjamin.ahrtr@gmail.com>
2024-09-05 08:46:22 +01:00

151 lines
3.4 KiB
Go

// Copyright 2024 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"fmt"
"io"
"os"
"go.etcd.io/etcd/server/v3/storage/mvcc"
)
func scanKeys(dbPath string, startRev int64) error {
pgSize, hwm, err := readPageAndHWMSize(dbPath)
if err != nil {
return fmt.Errorf("failed to read page and HWM size: %w", err)
}
for pageID := uint64(2); pageID < hwm; {
p, _, err := readPage(dbPath, pgSize, pageID)
if err != nil {
fmt.Fprintf(os.Stderr, "Reading page %d failed: %v. Continuting...\n", pageID, err)
pageID++
continue
}
if !p.isLeafPage() {
pageID++
continue
}
for i := uint16(0); i < p.count; i++ {
e := p.leafPageElement(i)
rev, err := bytesToBucketKey(e.key())
if err != nil {
if exceptionCheck(e.key()) {
break
}
fmt.Fprintf(os.Stderr, "Decoding revision failed, pageID: %d, index: %d, key: %x, error: %v\n", pageID, i, string(e.key()), err)
continue
}
if startRev != 0 && rev.Main < startRev {
continue
}
fmt.Printf("pageID=%d, index=%d/%d, ", pageID, i, p.count-1)
keyDecoder(e.key(), e.value())
}
pageID += uint64(p.overflow) + 1
}
return nil
}
func bytesToBucketKey(key []byte) (rev mvcc.BucketKey, err error) {
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("BytesToBucketKey failed: %v", r)
}
}()
rev = mvcc.BytesToBucketKey(key)
return rev, err
}
func readPageAndHWMSize(dbPath string) (uint64, uint64, error) {
f, err := os.Open(dbPath)
if err != nil {
return 0, 0, err
}
defer f.Close()
// read 4KB chunk
buf := make([]byte, 4096)
if _, err := io.ReadFull(f, buf); err != nil {
return 0, 0, err
}
m := loadPageMeta(buf)
if m.magic != magic {
return 0, 0, fmt.Errorf("the Meta Page has wrong (unexpected) magic")
}
return uint64(m.pageSize), m.pgid, nil
}
func readPage(dbPath string, pageSize uint64, pageID uint64) (*page, []byte, error) {
f, err := os.Open(dbPath)
if err != nil {
return nil, nil, err
}
defer f.Close()
buf := make([]byte, pageSize)
if _, err := f.ReadAt(buf, int64(pageID*pageSize)); err != nil {
return nil, nil, err
}
p := loadPage(buf)
if p.id != pageID {
return nil, nil, fmt.Errorf("unexpected page id: %d, wanted: %d", p.id, pageID)
}
if p.overflow == 0 {
return p, buf, nil
}
buf = make([]byte, (uint64(p.overflow)+1)*pageSize)
if _, err := f.ReadAt(buf, int64(pageID*pageSize)); err != nil {
return nil, nil, err
}
p = loadPage(buf)
if p.id != pageID {
return nil, nil, fmt.Errorf("unexpected page id: %d, wanted: %d", p.id, pageID)
}
return p, buf, nil
}
func exceptionCheck(key []byte) bool {
whiteKeyList := map[string]struct{}{
"alarm": {},
"auth": {},
"authRoles": {},
"authUsers": {},
"cluster": {},
"key": {},
"lease": {},
"members": {},
"members_removed": {},
"meta": {},
}
_, ok := whiteKeyList[string(key)]
return ok
}