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Help to recover from corrupted levelqueue (#24912)

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gitea.com experienced the corrupted LevelQueue bug again.

I think the problem is clear now: if the keys in LevelDB went
out-of-sync, the LevelQueue itself doesn't have the ability to recover,
eg:

* LevelQueue.Len() reports 100
* LevelQueue.LPop() reports ErrNotFound = errors.New("no key found")

So it needs to dive into the LevelDB to remove all keys to recover the
corrupted LevelQueue.

More comments are in TestCorruptedLevelQueue.
This commit is contained in:
wxiaoguang 2023-05-29 10:52:32 +08:00 • committed by GitHub
parent 8faf9465b3
commit 84c8ab9fd1
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 162 additions and 55 deletions
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39
modules/queue/base_levelqueue.go
View file

@ -5,16 +5,21 @@ package queue
import (
"context"
"sync/atomic"
"code.gitea.io/gitea/modules/nosql"
"code.gitea.io/gitea/modules/queue/lqinternal"
"gitea.com/lunny/levelqueue"
"github.com/syndtr/goleveldb/leveldb"
)
type baseLevelQueue struct {
internal *levelqueue.Queue
conn string
cfg *BaseConfig
internal atomic.Pointer[levelqueue.Queue]
conn string
cfg *BaseConfig
db *leveldb.DB
}
var _ baseQueue = (*baseLevelQueue)(nil)
@ -31,21 +36,23 @@ func newBaseLevelQueueSimple(cfg *BaseConfig) (baseQueue, error) {
if err != nil {
return nil, err
}
q := &baseLevelQueue{conn: conn, cfg: cfg}
q.internal, err = levelqueue.NewQueue(db, []byte(cfg.QueueFullName), false)
q := &baseLevelQueue{conn: conn, cfg: cfg, db: db}
lq, err := levelqueue.NewQueue(db, []byte(cfg.QueueFullName), false)
if err != nil {
return nil, err
}
q.internal.Store(lq)
return q, nil
}
func (q *baseLevelQueue) PushItem(ctx context.Context, data []byte) error {
return baseLevelQueueCommon(q.cfg, q.internal, nil).PushItem(ctx, data)
c := baseLevelQueueCommon(q.cfg, nil, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PushItem(ctx, data)
}
func (q *baseLevelQueue) PopItem(ctx context.Context) ([]byte, error) {
return baseLevelQueueCommon(q.cfg, q.internal, nil).PopItem(ctx)
c := baseLevelQueueCommon(q.cfg, nil, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PopItem(ctx)
}
func (q *baseLevelQueue) HasItem(ctx context.Context, data []byte) (bool, error) {
@ -53,20 +60,24 @@ func (q *baseLevelQueue) HasItem(ctx context.Context, data []byte) (bool, error)
}
func (q *baseLevelQueue) Len(ctx context.Context) (int, error) {
return int(q.internal.Len()), nil
return int(q.internal.Load().Len()), nil
}
func (q *baseLevelQueue) Close() error {
err := q.internal.Close()
err := q.internal.Load().Close()
_ = nosql.GetManager().CloseLevelDB(q.conn)
q.db = nil // the db is not managed by us, it's managed by the nosql manager
return err
}
func (q *baseLevelQueue) RemoveAll(ctx context.Context) error {
for q.internal.Len() > 0 {
if _, err := q.internal.LPop(); err != nil {
return err
}
lqinternal.RemoveLevelQueueKeys(q.db, []byte(q.cfg.QueueFullName))
lq, err := levelqueue.NewQueue(q.db, []byte(q.cfg.QueueFullName), false)
if err != nil {
return err
}
old := q.internal.Load()
q.internal.Store(lq)
_ = old.Close() // Not ideal for concurrency. Luckily, the levelqueue only sets its db=nil because it doesn't manage the db, so far so good
return nil
}

17
modules/queue/base_levelqueue_common.go
View file

@ -17,6 +17,7 @@ import (
"github.com/syndtr/goleveldb/leveldb"
)
// baseLevelQueuePushPoper is the common interface for levelqueue.Queue and levelqueue.UniqueQueue
type baseLevelQueuePushPoper interface {
RPush(data []byte) error
LPop() ([]byte, error)
@ -24,9 +25,9 @@ type baseLevelQueuePushPoper interface {
}
type baseLevelQueueCommonImpl struct {
length int
internal baseLevelQueuePushPoper
mu *sync.Mutex
length int
internalFunc func() baseLevelQueuePushPoper
mu *sync.Mutex
}
func (q *baseLevelQueueCommonImpl) PushItem(ctx context.Context, data []byte) error {
@ -36,11 +37,11 @@ func (q *baseLevelQueueCommonImpl) PushItem(ctx context.Context, data []byte) er
defer q.mu.Unlock()
}
cnt := int(q.internal.Len())
cnt := int(q.internalFunc().Len())
if cnt >= q.length {
return true, nil
}
retry, err = false, q.internal.RPush(data)
retry, err = false, q.internalFunc().RPush(data)
if err == levelqueue.ErrAlreadyInQueue {
err = ErrAlreadyInQueue
}
@ -55,7 +56,7 @@ func (q *baseLevelQueueCommonImpl) PopItem(ctx context.Context) ([]byte, error)
defer q.mu.Unlock()
}
data, err = q.internal.LPop()
data, err = q.internalFunc().LPop()
if err == levelqueue.ErrNotFound {
return true, nil, nil
}
@ -66,8 +67,8 @@ func (q *baseLevelQueueCommonImpl) PopItem(ctx context.Context) ([]byte, error)
})
}
func baseLevelQueueCommon(cfg *BaseConfig, internal baseLevelQueuePushPoper, mu *sync.Mutex) *baseLevelQueueCommonImpl {
return &baseLevelQueueCommonImpl{length: cfg.Length, internal: internal}
func baseLevelQueueCommon(cfg *BaseConfig, mu *sync.Mutex, internalFunc func() baseLevelQueuePushPoper) *baseLevelQueueCommonImpl {
return &baseLevelQueueCommonImpl{length: cfg.Length, mu: mu, internalFunc: internalFunc}
}
func prepareLevelDB(cfg *BaseConfig) (conn string, db *leveldb.DB, err error) {

55
modules/queue/base_levelqueue_test.go
View file

@ -6,9 +6,12 @@ package queue
import (
"testing"
"code.gitea.io/gitea/modules/queue/lqinternal"
"code.gitea.io/gitea/modules/setting"
"gitea.com/lunny/levelqueue"
"github.com/stretchr/testify/assert"
"github.com/syndtr/goleveldb/leveldb"
)
func TestBaseLevelDB(t *testing.T) {
@ -21,3 +24,55 @@ func TestBaseLevelDB(t *testing.T) {
testQueueBasic(t, newBaseLevelQueueSimple, toBaseConfig("baseLevelQueue", setting.QueueSettings{Datadir: t.TempDir() + "/queue-test", Length: 10}), false)
testQueueBasic(t, newBaseLevelQueueUnique, toBaseConfig("baseLevelQueueUnique", setting.QueueSettings{ConnStr: "leveldb://" + t.TempDir() + "/queue-test", Length: 10}), true)
}
func TestCorruptedLevelQueue(t *testing.T) {
// sometimes the levelqueue could be in a corrupted state, this test is to make sure it can recover from it
dbDir := t.TempDir() + "/levelqueue-test"
db, err := leveldb.OpenFile(dbDir, nil)
if !assert.NoError(t, err) {
return
}
defer db.Close()
assert.NoError(t, db.Put([]byte("other-key"), []byte("other-value"), nil))
nameQueuePrefix := []byte("queue_name")
nameSetPrefix := []byte("set_name")
lq, err := levelqueue.NewUniqueQueue(db, nameQueuePrefix, nameSetPrefix, false)
assert.NoError(t, err)
assert.NoError(t, lq.RPush([]byte("item-1")))
itemKey := lqinternal.QueueItemKeyBytes(nameQueuePrefix, 1)
itemValue, err := db.Get(itemKey, nil)
assert.NoError(t, err)
assert.Equal(t, []byte("item-1"), itemValue)
// there should be 5 keys in db: queue low, queue high, 1 queue item, 1 set item, and "other-key"
keys := lqinternal.ListLevelQueueKeys(db)
assert.Len(t, keys, 5)
// delete the queue item key, to corrupt the queue
assert.NoError(t, db.Delete(itemKey, nil))
// now the queue is corrupted, it never works again
_, err = lq.LPop()
assert.ErrorIs(t, err, levelqueue.ErrNotFound)
assert.NoError(t, lq.Close())
// remove all the queue related keys to reset the queue
lqinternal.RemoveLevelQueueKeys(db, nameQueuePrefix)
lqinternal.RemoveLevelQueueKeys(db, nameSetPrefix)
// now there should be only 1 key in db: "other-key"
keys = lqinternal.ListLevelQueueKeys(db)
assert.Len(t, keys, 1)
assert.Equal(t, []byte("other-key"), keys[0])
// re-create a queue from db
lq, err = levelqueue.NewUniqueQueue(db, nameQueuePrefix, nameSetPrefix, false)
assert.NoError(t, err)
assert.NoError(t, lq.RPush([]byte("item-new-1")))
// now the queue works again
itemValue, err = lq.LPop()
assert.NoError(t, err)
assert.Equal(t, []byte("item-new-1"), itemValue)
assert.NoError(t, lq.Close())
}

58
modules/queue/base_levelqueue_unique.go
View file

@ -6,18 +6,21 @@ package queue
import (
"context"
"sync"
"unsafe"
"sync/atomic"
"code.gitea.io/gitea/modules/nosql"
"code.gitea.io/gitea/modules/queue/lqinternal"
"gitea.com/lunny/levelqueue"
"github.com/syndtr/goleveldb/leveldb"
)
type baseLevelQueueUnique struct {
internal *levelqueue.UniqueQueue
conn string
cfg *BaseConfig
internal atomic.Pointer[levelqueue.UniqueQueue]
conn string
cfg *BaseConfig
db *leveldb.DB
mu sync.Mutex // the levelqueue.UniqueQueue is not thread-safe, there is no mutex protecting the underlying queue&set together
}
@ -29,39 +32,42 @@ func newBaseLevelQueueUnique(cfg *BaseConfig) (baseQueue, error) {
if err != nil {
return nil, err
}
q := &baseLevelQueueUnique{conn: conn, cfg: cfg}
q.internal, err = levelqueue.NewUniqueQueue(db, []byte(cfg.QueueFullName), []byte(cfg.SetFullName), false)
q := &baseLevelQueueUnique{conn: conn, cfg: cfg, db: db}
lq, err := levelqueue.NewUniqueQueue(db, []byte(cfg.QueueFullName), []byte(cfg.SetFullName), false)
if err != nil {
return nil, err
}
q.internal.Store(lq)
return q, nil
}
func (q *baseLevelQueueUnique) PushItem(ctx context.Context, data []byte) error {
return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PushItem(ctx, data)
c := baseLevelQueueCommon(q.cfg, &q.mu, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PushItem(ctx, data)
}
func (q *baseLevelQueueUnique) PopItem(ctx context.Context) ([]byte, error) {
return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PopItem(ctx)
c := baseLevelQueueCommon(q.cfg, &q.mu, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PopItem(ctx)
}
func (q *baseLevelQueueUnique) HasItem(ctx context.Context, data []byte) (bool, error) {
q.mu.Lock()
defer q.mu.Unlock()
return q.internal.Has(data)
return q.internal.Load().Has(data)
}
func (q *baseLevelQueueUnique) Len(ctx context.Context) (int, error) {
q.mu.Lock()
defer q.mu.Unlock()
return int(q.internal.Len()), nil
return int(q.internal.Load().Len()), nil
}
func (q *baseLevelQueueUnique) Close() error {
q.mu.Lock()
defer q.mu.Unlock()
err := q.internal.Close()
err := q.internal.Load().Close()
q.db = nil // the db is not managed by us, it's managed by the nosql manager
_ = nosql.GetManager().CloseLevelDB(q.conn)
return err
}
@ -69,28 +75,14 @@ func (q *baseLevelQueueUnique) Close() error {
func (q *baseLevelQueueUnique) RemoveAll(ctx context.Context) error {
q.mu.Lock()
defer q.mu.Unlock()
type levelUniqueQueue struct {
q *levelqueue.Queue
set *levelqueue.Set
db *leveldb.DB
}
lq := (*levelUniqueQueue)(unsafe.Pointer(q.internal))
for lq.q.Len() > 0 {
if _, err := lq.q.LPop(); err != nil {
return err
}
}
// the "set" must be cleared after the "list" because there is no transaction.
// it's better to have duplicate items than losing items.
members, err := lq.set.Members()
lqinternal.RemoveLevelQueueKeys(q.db, []byte(q.cfg.QueueFullName))
lqinternal.RemoveLevelQueueKeys(q.db, []byte(q.cfg.SetFullName))
lq, err := levelqueue.NewUniqueQueue(q.db, []byte(q.cfg.QueueFullName), []byte(q.cfg.SetFullName), false)
if err != nil {
return err // seriously corrupted
}
for _, v := range members {
_, _ = lq.set.Remove(v)
return err
}
old := q.internal.Load()
q.internal.Store(lq)
_ = old.Close() // Not ideal for concurrency. Luckily, the levelqueue only sets its db=nil because it doesn't manage the db, so far so good
return nil
}

48
modules/queue/lqinternal/lqinternal.go Normal file
View file

@ -0,0 +1,48 @@
// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package lqinternal
import (
"bytes"
"encoding/binary"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/opt"
)
func QueueItemIDBytes(id int64) []byte {
buf := make([]byte, 8)
binary.PutVarint(buf, id)
return buf
}
func QueueItemKeyBytes(prefix []byte, id int64) []byte {
key := make([]byte, len(prefix), len(prefix)+1+8)
copy(key, prefix)
key = append(key, '-')
return append(key, QueueItemIDBytes(id)...)
}
func RemoveLevelQueueKeys(db *leveldb.DB, namePrefix []byte) {
keyPrefix := make([]byte, len(namePrefix)+1)
copy(keyPrefix, namePrefix)
keyPrefix[len(namePrefix)] = '-'
it := db.NewIterator(nil, &opt.ReadOptions{Strict: opt.NoStrict})
defer it.Release()
for it.Next() {
if bytes.HasPrefix(it.Key(), keyPrefix) {
_ = db.Delete(it.Key(), nil)
}
}
}
func ListLevelQueueKeys(db *leveldb.DB) (res [][]byte) {
it := db.NewIterator(nil, &opt.ReadOptions{Strict: opt.NoStrict})
defer it.Release()
for it.Next() {
res = append(res, it.Key())
}
return res
}