hermez-node/db/kvdb/kvdb.go
db/kvdb/kvdb.goRaw
1// Package kvdb provides a key-value database with Checkpoints & Resets system
2package kvdb
3
4import (
5 "fmt"
6 "io/ioutil"
7 "os"
8 "path"
9 "sort"
10 "strings"
11
12 "github.com/hermeznetwork/hermez-node/common"
13 "github.com/hermeznetwork/hermez-node/log"
14 "github.com/hermeznetwork/tracerr"
15 "github.com/iden3/go-merkletree/db"
16 "github.com/iden3/go-merkletree/db/pebble"
17)
18
19const (
20 // PathBatchNum defines the subpath of the Batch Checkpoint in the
21 // subpath of the KVDB
22 PathBatchNum = "BatchNum"
23 // PathCurrent defines the subpath of the current Batch in the subpath
24 // of the KVDB
25 PathCurrent = "current"
26)
27
28var (
29 // KeyCurrentBatch is used as key in the db to store the current BatchNum
30 KeyCurrentBatch = []byte("k:currentbatch")
31 // keyCurrentIdx is used as key in the db to store the CurrentIdx
32 keyCurrentIdx = []byte("k:idx")
33)
34
35// KVDB represents the Key-Value DB object
36type KVDB struct {
37 path string
38 db *pebble.Storage
39 // CurrentIdx holds the current Idx that the BatchBuilder is using
40 CurrentIdx common.Idx
41 CurrentBatch common.BatchNum
42 keep int
43}
44
45// NewKVDB creates a new KVDB, allowing to use an in-memory or in-disk storage.
46// Checkpoints older than the value defined by `keep` will be deleted.
47func NewKVDB(pathDB string, keep int) (*KVDB, error) {
48 var sto *pebble.Storage
49 var err error
50 sto, err = pebble.NewPebbleStorage(path.Join(pathDB, PathCurrent), false)
51 if err != nil {
52 return nil, tracerr.Wrap(err)
53 }
54
55 kvdb := &KVDB{
56 path: pathDB,
57 db: sto,
58 keep: keep,
59 }
60 // load currentBatch
61 kvdb.CurrentBatch, err = kvdb.GetCurrentBatch()
62 if err != nil {
63 return nil, tracerr.Wrap(err)
64 }
65
66 // make reset (get checkpoint) at currentBatch
67 err = kvdb.reset(kvdb.CurrentBatch, false)
68 if err != nil {
69 return nil, tracerr.Wrap(err)
70 }
71
72 return kvdb, nil
73}
74
75// DB returns the *pebble.Storage from the KVDB
76func (kvdb *KVDB) DB() *pebble.Storage {
77 return kvdb.db
78}
79
80// StorageWithPrefix returns the db.Storage with the given prefix from the
81// current KVDB
82func (kvdb *KVDB) StorageWithPrefix(prefix []byte) db.Storage {
83 return kvdb.db.WithPrefix(prefix)
84}
85
86// Reset resets the KVDB to the checkpoint at the given batchNum. Reset does
87// not delete the checkpoints between old current and the new current, those
88// checkpoints will remain in the storage, and eventually will be deleted when
89// MakeCheckpoint overwrites them.
90func (kvdb *KVDB) Reset(batchNum common.BatchNum) error {
91 return kvdb.reset(batchNum, true)
92}
93
94// reset resets the KVDB to the checkpoint at the given batchNum. Reset does
95// not delete the checkpoints between old current and the new current, those
96// checkpoints will remain in the storage, and eventually will be deleted when
97// MakeCheckpoint overwrites them. `closeCurrent` will close the currently
98// opened db before doing the reset.
99func (kvdb *KVDB) reset(batchNum common.BatchNum, closeCurrent bool) error {
100 currentPath := path.Join(kvdb.path, PathCurrent)
101
102 if closeCurrent {
103 if err := kvdb.db.Pebble().Close(); err != nil {
104 return tracerr.Wrap(err)
105 }
106 }
107 // remove 'current'
108 err := os.RemoveAll(currentPath)
109 if err != nil {
110 return tracerr.Wrap(err)
111 }
112 // remove all checkpoints > batchNum
113 for i := batchNum + 1; i <= kvdb.CurrentBatch; i++ {
114 if err := kvdb.DeleteCheckpoint(i); err != nil {
115 return tracerr.Wrap(err)
116 }
117 }
118 if batchNum == 0 {
119 // if batchNum == 0, open the new fresh 'current'
120 sto, err := pebble.NewPebbleStorage(currentPath, false)
121 if err != nil {
122 return tracerr.Wrap(err)
123 }
124 kvdb.db = sto
125 kvdb.CurrentIdx = 255
126 kvdb.CurrentBatch = batchNum
127
128 return nil
129 }
130
131 checkpointPath := path.Join(kvdb.path, fmt.Sprintf("%s%d", PathBatchNum, batchNum))
132 // copy 'BatchNumX' to 'current'
133 err = pebbleMakeCheckpoint(checkpointPath, currentPath)
134 if err != nil {
135 return tracerr.Wrap(err)
136 }
137
138 // open the new 'current'
139 sto, err := pebble.NewPebbleStorage(currentPath, false)
140 if err != nil {
141 return tracerr.Wrap(err)
142 }
143 kvdb.db = sto
144
145 // get currentBatch num
146 kvdb.CurrentBatch, err = kvdb.GetCurrentBatch()
147 if err != nil {
148 return tracerr.Wrap(err)
149 }
150 // idx is obtained from the statedb reset
151 kvdb.CurrentIdx, err = kvdb.GetCurrentIdx()
152 if err != nil {
153 return tracerr.Wrap(err)
154 }
155
156 return nil
157}
158
159// ResetFromSynchronizer performs a reset in the KVDB getting the state from
160// synchronizerKVDB for the given batchNum.
161func (kvdb *KVDB) ResetFromSynchronizer(batchNum common.BatchNum, synchronizerKVDB *KVDB) error {
162 if synchronizerKVDB == nil {
163 return tracerr.Wrap(fmt.Errorf("synchronizerKVDB can not be nil"))
164 }
165
166 if batchNum == 0 {
167 kvdb.CurrentIdx = 0
168 return nil
169 }
170 synchronizerCheckpointPath := path.Join(synchronizerKVDB.path,
171 fmt.Sprintf("%s%d", PathBatchNum, batchNum))
172 checkpointPath := path.Join(kvdb.path, fmt.Sprintf("%s%d", PathBatchNum, batchNum))
173 currentPath := path.Join(kvdb.path, PathCurrent)
174
175 // use checkpoint from synchronizerKVDB
176 if _, err := os.Stat(synchronizerCheckpointPath); os.IsNotExist(err) {
177 // if synchronizerKVDB does not have checkpoint at batchNum, return err
178 return tracerr.Wrap(fmt.Errorf("Checkpoint \"%v\" not exist in Synchronizer",
179 synchronizerCheckpointPath))
180 }
181
182 if err := kvdb.db.Pebble().Close(); err != nil {
183 return tracerr.Wrap(err)
184 }
185 // remove 'current'
186 err := os.RemoveAll(currentPath)
187 if err != nil {
188 return tracerr.Wrap(err)
189 }
190 // copy synchronizer'BatchNumX' to 'current'
191 err = pebbleMakeCheckpoint(synchronizerCheckpointPath, currentPath)
192 if err != nil {
193 return tracerr.Wrap(err)
194 }
195 // copy synchronizer'BatchNumX' to 'BatchNumX'
196 err = pebbleMakeCheckpoint(synchronizerCheckpointPath, checkpointPath)
197 if err != nil {
198 return tracerr.Wrap(err)
199 }
200
201 // open the new 'current'
202 sto, err := pebble.NewPebbleStorage(currentPath, false)
203 if err != nil {
204 return tracerr.Wrap(err)
205 }
206 kvdb.db = sto
207
208 // get currentBatch num
209 kvdb.CurrentBatch, err = kvdb.GetCurrentBatch()
210 if err != nil {
211 return tracerr.Wrap(err)
212 }
213
214 return nil
215}
216
217// GetCurrentBatch returns the current BatchNum stored in the KVDB
218func (kvdb *KVDB) GetCurrentBatch() (common.BatchNum, error) {
219 cbBytes, err := kvdb.db.Get(KeyCurrentBatch)
220 if tracerr.Unwrap(err) == db.ErrNotFound {
221 return 0, nil
222 }
223 if err != nil {
224 return 0, tracerr.Wrap(err)
225 }
226 return common.BatchNumFromBytes(cbBytes)
227}
228
229// setCurrentBatch stores the current BatchNum in the KVDB
230func (kvdb *KVDB) setCurrentBatch() error {
231 tx, err := kvdb.db.NewTx()
232 if err != nil {
233 return tracerr.Wrap(err)
234 }
235 err = tx.Put(KeyCurrentBatch, kvdb.CurrentBatch.Bytes())
236 if err != nil {
237 return tracerr.Wrap(err)
238 }
239 if err := tx.Commit(); err != nil {
240 return tracerr.Wrap(err)
241 }
242 return nil
243}
244
245// GetCurrentIdx returns the stored Idx from the KVDB, which is the last Idx
246// used for an Account in the KVDB.
247func (kvdb *KVDB) GetCurrentIdx() (common.Idx, error) {
248 idxBytes, err := kvdb.db.Get(keyCurrentIdx)
249 if tracerr.Unwrap(err) == db.ErrNotFound {
250 return 0, nil
251 }
252 if err != nil {
253 return 0, tracerr.Wrap(err)
254 }
255 return common.IdxFromBytes(idxBytes[:])
256}
257
258// SetCurrentIdx stores Idx in the KVDB
259func (kvdb *KVDB) SetCurrentIdx(idx common.Idx) error {
260 kvdb.CurrentIdx = idx
261
262 tx, err := kvdb.db.NewTx()
263 if err != nil {
264 return tracerr.Wrap(err)
265 }
266 idxBytes, err := idx.Bytes()
267 if err != nil {
268 return tracerr.Wrap(err)
269 }
270 err = tx.Put(keyCurrentIdx, idxBytes[:])
271 if err != nil {
272 return tracerr.Wrap(err)
273 }
274 if err := tx.Commit(); err != nil {
275 return tracerr.Wrap(err)
276 }
277 return nil
278}
279
280// MakeCheckpoint does a checkpoint at the given batchNum in the defined path.
281// Internally this advances & stores the current BatchNum, and then stores a
282// Checkpoint of the current state of the KVDB.
283func (kvdb *KVDB) MakeCheckpoint() error {
284 // advance currentBatch
285 kvdb.CurrentBatch++
286 log.Debugw("Making KVDB checkpoint", "batch", kvdb.CurrentBatch)
287
288 checkpointPath := path.Join(kvdb.path, fmt.Sprintf("%s%d", PathBatchNum, kvdb.CurrentBatch))
289
290 if err := kvdb.setCurrentBatch(); err != nil {
291 return tracerr.Wrap(err)
292 }
293
294 // if checkpoint BatchNum already exist in disk, delete it
295 if _, err := os.Stat(checkpointPath); !os.IsNotExist(err) {
296 err := os.RemoveAll(checkpointPath)
297 if err != nil {
298 return tracerr.Wrap(err)
299 }
300 } else if err != nil && !os.IsNotExist(err) {
301 return tracerr.Wrap(err)
302 }
303
304 // execute Checkpoint
305 if err := kvdb.db.Pebble().Checkpoint(checkpointPath); err != nil {
306 return tracerr.Wrap(err)
307 }
308 // delete old checkpoints
309 if err := kvdb.deleteOldCheckpoints(); err != nil {
310 return tracerr.Wrap(err)
311 }
312
313 return nil
314}
315
316// DeleteCheckpoint removes if exist the checkpoint of the given batchNum
317func (kvdb *KVDB) DeleteCheckpoint(batchNum common.BatchNum) error {
318 checkpointPath := path.Join(kvdb.path, fmt.Sprintf("%s%d", PathBatchNum, batchNum))
319
320 if _, err := os.Stat(checkpointPath); os.IsNotExist(err) {
321 return tracerr.Wrap(fmt.Errorf("Checkpoint with batchNum %d does not exist in DB", batchNum))
322 }
323
324 return os.RemoveAll(checkpointPath)
325}
326
327// ListCheckpoints returns the list of batchNums of the checkpoints, sorted.
328// If there's a gap between the list of checkpoints, an error is returned.
329func (kvdb *KVDB) ListCheckpoints() ([]int, error) {
330 files, err := ioutil.ReadDir(kvdb.path)
331 if err != nil {
332 return nil, tracerr.Wrap(err)
333 }
334 checkpoints := []int{}
335 var checkpoint int
336 pattern := fmt.Sprintf("%s%%d", PathBatchNum)
337 for _, file := range files {
338 fileName := file.Name()
339 if file.IsDir() && strings.HasPrefix(fileName, PathBatchNum) {
340 if _, err := fmt.Sscanf(fileName, pattern, &checkpoint); err != nil {
341 return nil, tracerr.Wrap(err)
342 }
343 checkpoints = append(checkpoints, checkpoint)
344 }
345 }
346 sort.Ints(checkpoints)
347 if len(checkpoints) > 0 {
348 first := checkpoints[0]
349 for _, checkpoint := range checkpoints[1:] {
350 first++
351 if checkpoint != first {
352 return nil, tracerr.Wrap(fmt.Errorf("checkpoint gap at %v", checkpoint))
353 }
354 }
355 }
356 return checkpoints, nil
357}
358
359// deleteOldCheckpoints deletes old checkpoints when there are more than
360// `s.keep` checkpoints
361func (kvdb *KVDB) deleteOldCheckpoints() error {
362 list, err := kvdb.ListCheckpoints()
363 if err != nil {
364 return tracerr.Wrap(err)
365 }
366 if len(list) > kvdb.keep {
367 for _, checkpoint := range list[:len(list)-kvdb.keep] {
368 if err := kvdb.DeleteCheckpoint(common.BatchNum(checkpoint)); err != nil {
369 return tracerr.Wrap(err)
370 }
371 }
372 }
373 return nil
374}
375
376func pebbleMakeCheckpoint(source, dest string) error {
377 // Remove dest folder (if it exists) before doing the checkpoint
378 if _, err := os.Stat(dest); !os.IsNotExist(err) {
379 err := os.RemoveAll(dest)
380 if err != nil {
381 return tracerr.Wrap(err)
382 }
383 } else if err != nil && !os.IsNotExist(err) {
384 return tracerr.Wrap(err)
385 }
386
387 sto, err := pebble.NewPebbleStorage(source, false)
388 if err != nil {
389 return tracerr.Wrap(err)
390 }
391 defer func() {
392 errClose := sto.Pebble().Close()
393 if errClose != nil {
394 log.Errorw("Pebble.Close", "err", errClose)
395 }
396 }()
397
398 // execute Checkpoint
399 err = sto.Pebble().Checkpoint(dest)
400 if err != nil {
401 return tracerr.Wrap(err)
402 }
403
404 return nil
405}