-
Notifications
You must be signed in to change notification settings - Fork 968
/
blocks_queue.go
470 lines (429 loc) · 15.3 KB
/
blocks_queue.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
package initialsync
import (
"context"
"errors"
"time"
"github.com/libp2p/go-libp2p/core/peer"
"github.com/prysmaticlabs/prysm/v5/beacon-chain/db"
"github.com/prysmaticlabs/prysm/v5/beacon-chain/p2p"
"github.com/prysmaticlabs/prysm/v5/beacon-chain/startup"
beaconsync "github.com/prysmaticlabs/prysm/v5/beacon-chain/sync"
"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
"github.com/prysmaticlabs/prysm/v5/time/slots"
"github.com/sirupsen/logrus"
)
const (
// queueStopCallTimeout is time allowed for queue to release resources when quitting.
queueStopCallTimeout = 1 * time.Second
// pollingInterval defines how often state machine needs to check for new events.
pollingInterval = 200 * time.Millisecond
// staleEpochTimeout is an period after which epoch's state is considered stale.
staleEpochTimeout = 1 * time.Second
// skippedMachineTimeout is a period after which skipped machine is considered as stuck
// and is reset (if machine is the last one, then all machines are reset and search for
// skipped slot or backtracking takes place).
skippedMachineTimeout = 10 * staleEpochTimeout
// lookaheadSteps is a limit on how many forward steps are loaded into queue.
// Each step is managed by assigned finite state machine. Must be >= 2.
lookaheadSteps = 4
// noRequiredPeersErrMaxRetries defines number of retries when no required peers are found.
noRequiredPeersErrMaxRetries = 1000
// noRequiredPeersErrRefreshInterval defines interval for which queue will be paused before
// making the next attempt to obtain data.
noRequiredPeersErrRefreshInterval = 15 * time.Second
// maxResetAttempts number of times stale FSM is reset, before backtracking is triggered.
maxResetAttempts = 4
// startBackSlots defines number of slots before the current head, which defines a start position
// of the initial machine. This allows more robustness in case of normal sync sets head to some
// orphaned block: in that case starting earlier and re-fetching blocks allows to reorganize chain.
startBackSlots = 32
)
var (
errQueueCtxIsDone = errors.New("queue's context is done, reinitialize")
errQueueTakesTooLongToStop = errors.New("queue takes too long to stop")
errInvalidInitialState = errors.New("invalid initial state")
errInputNotFetchRequestParams = errors.New("input data is not type *fetchRequestParams")
errNoRequiredPeers = errors.New("no peers with required blocks are found")
)
const (
modeStopOnFinalizedEpoch syncMode = iota
modeNonConstrained
)
// syncMode specifies sync mod type.
type syncMode uint8
// blocksQueueConfig is a config to setup block queue service.
type blocksQueueConfig struct {
blocksFetcher *blocksFetcher
chain blockchainService
clock *startup.Clock
ctxMap beaconsync.ContextByteVersions
highestExpectedSlot primitives.Slot
p2p p2p.P2P
db db.ReadOnlyDatabase
mode syncMode
}
// blocksQueue is a priority queue that serves as a intermediary between block fetchers (producers)
// and block processing goroutine (consumer). Consumer can rely on order of incoming blocks.
type blocksQueue struct {
ctx context.Context
cancel context.CancelFunc
smm *stateMachineManager
blocksFetcher *blocksFetcher
chain blockchainService
highestExpectedSlot primitives.Slot
mode syncMode
exitConditions struct {
noRequiredPeersErrRetries int
}
fetchedData chan *blocksQueueFetchedData // output channel for ready blocks
staleEpochs map[primitives.Epoch]uint8 // counter to keep track of stale FSMs
quit chan struct{} // termination notifier
}
// blocksQueueFetchedData is a data container that is returned from a queue on each step.
type blocksQueueFetchedData struct {
pid peer.ID
bwb []blocks.BlockWithROBlobs
}
// newBlocksQueue creates initialized priority queue.
func newBlocksQueue(ctx context.Context, cfg *blocksQueueConfig) *blocksQueue {
ctx, cancel := context.WithCancel(ctx)
blocksFetcher := cfg.blocksFetcher
if blocksFetcher == nil {
blocksFetcher = newBlocksFetcher(ctx, &blocksFetcherConfig{
ctxMap: cfg.ctxMap,
chain: cfg.chain,
p2p: cfg.p2p,
db: cfg.db,
clock: cfg.clock,
})
}
highestExpectedSlot := cfg.highestExpectedSlot
if highestExpectedSlot == 0 {
if cfg.mode == modeStopOnFinalizedEpoch {
highestExpectedSlot = blocksFetcher.bestFinalizedSlot()
} else {
highestExpectedSlot = blocksFetcher.bestNonFinalizedSlot()
}
}
// Override fetcher's sync mode.
blocksFetcher.mode = cfg.mode
queue := &blocksQueue{
ctx: ctx,
cancel: cancel,
highestExpectedSlot: highestExpectedSlot,
blocksFetcher: blocksFetcher,
chain: cfg.chain,
mode: cfg.mode,
fetchedData: make(chan *blocksQueueFetchedData, 1),
quit: make(chan struct{}),
staleEpochs: make(map[primitives.Epoch]uint8),
}
// Configure state machines.
queue.smm = newStateMachineManager()
queue.smm.addEventHandler(eventTick, stateNew, queue.onScheduleEvent(ctx))
queue.smm.addEventHandler(eventDataReceived, stateScheduled, queue.onDataReceivedEvent(ctx))
queue.smm.addEventHandler(eventTick, stateDataParsed, queue.onReadyToSendEvent(ctx))
queue.smm.addEventHandler(eventTick, stateSkipped, queue.onProcessSkippedEvent(ctx))
queue.smm.addEventHandler(eventTick, stateSent, queue.onCheckStaleEvent(ctx))
return queue
}
// start boots up the queue processing.
func (q *blocksQueue) start() error {
select {
case <-q.ctx.Done():
return errQueueCtxIsDone
default:
go q.loop()
return nil
}
}
// stop terminates all queue operations.
func (q *blocksQueue) stop() error {
q.cancel()
select {
case <-q.quit:
return nil
case <-time.After(queueStopCallTimeout):
return errQueueTakesTooLongToStop
}
}
// loop is a main queue loop.
func (q *blocksQueue) loop() {
defer close(q.quit)
defer func() {
q.blocksFetcher.stop()
close(q.fetchedData)
}()
if err := q.blocksFetcher.start(); err != nil {
log.WithError(err).Debug("Can not start blocks provider")
}
// Define initial state machines.
startSlot := q.chain.HeadSlot()
if startSlot > startBackSlots {
startSlot -= startBackSlots
}
blocksPerRequest := q.blocksFetcher.blocksPerPeriod
for i := startSlot; i < startSlot.Add(blocksPerRequest*lookaheadSteps); i += primitives.Slot(blocksPerRequest) {
q.smm.addStateMachine(i)
}
ticker := time.NewTicker(pollingInterval)
defer ticker.Stop()
for {
if waitHighestExpectedSlot(q) {
continue
}
log.WithFields(logrus.Fields{
"highestExpectedSlot": q.highestExpectedSlot,
"headSlot": q.chain.HeadSlot(),
"state": q.smm.String(),
"staleEpoch": q.staleEpochs,
}).Trace("tick")
select {
case <-ticker.C:
for _, key := range q.smm.keys {
fsm := q.smm.machines[key]
if err := fsm.trigger(eventTick, nil); err != nil {
log.WithFields(logrus.Fields{
"highestExpectedSlot": q.highestExpectedSlot,
"noRequiredPeersErrRetries": q.exitConditions.noRequiredPeersErrRetries,
"event": eventTick,
"epoch": slots.ToEpoch(fsm.start),
"start": fsm.start,
"error": err.Error(),
}).Debug("Can not trigger event")
if errors.Is(err, errNoRequiredPeers) {
forceExit := q.exitConditions.noRequiredPeersErrRetries > noRequiredPeersErrMaxRetries
if q.mode == modeStopOnFinalizedEpoch || forceExit {
q.cancel()
} else {
q.exitConditions.noRequiredPeersErrRetries++
log.Debug("Waiting for finalized peers")
time.Sleep(noRequiredPeersErrRefreshInterval)
}
continue
}
}
// Do garbage collection, and advance sliding window forward.
if q.chain.HeadSlot() >= fsm.start.Add(blocksPerRequest-1) {
highestStartSlot, err := q.smm.highestStartSlot()
if err != nil {
log.WithError(err).Debug("Cannot obtain highest epoch state number")
continue
}
if err := q.smm.removeStateMachine(fsm.start); err != nil {
log.WithError(err).Debug("Can not remove state machine")
}
if len(q.smm.machines) < lookaheadSteps {
q.smm.addStateMachine(highestStartSlot.Add(blocksPerRequest))
}
}
}
case response, ok := <-q.blocksFetcher.requestResponses():
if !ok {
log.Debug("Fetcher closed output channel")
q.cancel()
return
}
// Update state of an epoch for which data is received.
if fsm, ok := q.smm.findStateMachine(response.start); ok {
if err := fsm.trigger(eventDataReceived, response); err != nil {
log.WithFields(logrus.Fields{
"event": eventDataReceived,
"epoch": slots.ToEpoch(fsm.start),
"error": err.Error(),
}).Debug("Can not process event")
fsm.setState(stateNew)
continue
}
}
case <-q.ctx.Done():
log.Debug("Context closed, exiting goroutine (blocks queue)")
return
}
}
}
func waitHighestExpectedSlot(q *blocksQueue) bool {
// Check highest expected slot when we approach chain's head slot.
if q.chain.HeadSlot() >= q.highestExpectedSlot {
// By the time initial sync is complete, highest slot may increase, re-check.
if q.mode == modeStopOnFinalizedEpoch {
if q.highestExpectedSlot < q.blocksFetcher.bestFinalizedSlot() {
q.highestExpectedSlot = q.blocksFetcher.bestFinalizedSlot()
return true
}
} else {
if q.highestExpectedSlot < q.blocksFetcher.bestNonFinalizedSlot() {
q.highestExpectedSlot = q.blocksFetcher.bestNonFinalizedSlot()
return true
}
}
log.WithField("slot", q.highestExpectedSlot).Debug("Highest expected slot reached")
q.cancel()
}
return false
}
// onScheduleEvent is an event called on newly arrived epochs. Transforms state to scheduled.
func (q *blocksQueue) onScheduleEvent(ctx context.Context) eventHandlerFn {
return func(m *stateMachine, in interface{}) (stateID, error) {
if m.state != stateNew {
return m.state, errInvalidInitialState
}
if m.start > q.highestExpectedSlot {
m.setState(stateSkipped)
return m.state, errSlotIsTooHigh
}
blocksPerRequest := q.blocksFetcher.blocksPerPeriod
if err := q.blocksFetcher.scheduleRequest(ctx, m.start, blocksPerRequest); err != nil {
return m.state, err
}
return stateScheduled, nil
}
}
// onDataReceivedEvent is an event called when data is received from fetcher.
func (q *blocksQueue) onDataReceivedEvent(ctx context.Context) eventHandlerFn {
return func(m *stateMachine, in interface{}) (stateID, error) {
if ctx.Err() != nil {
return m.state, ctx.Err()
}
if m.state != stateScheduled {
return m.state, errInvalidInitialState
}
response, ok := in.(*fetchRequestResponse)
if !ok {
return m.state, errInputNotFetchRequestParams
}
if response.err != nil {
if errors.Is(response.err, errSlotIsTooHigh) {
// Current window is already too big, re-request previous epochs.
for _, fsm := range q.smm.machines {
if fsm.start < response.start && fsm.state == stateSkipped {
fsm.setState(stateNew)
}
}
}
if errors.Is(response.err, beaconsync.ErrInvalidFetchedData) {
// Peer returned invalid data, penalize.
q.blocksFetcher.p2p.Peers().Scorers().BadResponsesScorer().Increment(m.pid)
log.WithField("pid", response.pid).Debug("Peer is penalized for invalid blocks")
}
return m.state, response.err
}
m.pid = response.pid
m.bwb = response.bwb
return stateDataParsed, nil
}
}
// onReadyToSendEvent is an event called to allow epochs with available blocks to send them downstream.
func (q *blocksQueue) onReadyToSendEvent(ctx context.Context) eventHandlerFn {
return func(m *stateMachine, in interface{}) (stateID, error) {
if ctx.Err() != nil {
return m.state, ctx.Err()
}
if m.state != stateDataParsed {
return m.state, errInvalidInitialState
}
if len(m.bwb) == 0 {
return stateSkipped, nil
}
send := func() (stateID, error) {
data := &blocksQueueFetchedData{
pid: m.pid,
bwb: m.bwb,
}
select {
case <-ctx.Done():
return m.state, ctx.Err()
case q.fetchedData <- data:
}
return stateSent, nil
}
// Make sure that we send epochs in a correct order.
// If machine is the first (has lowest start block), send.
if m.isFirst() {
return send()
}
// Make sure that previous epoch is already processed.
for _, fsm := range q.smm.machines {
// Review only previous slots.
if fsm.start < m.start {
switch fsm.state {
case stateNew, stateScheduled, stateDataParsed:
return m.state, nil
}
}
}
return send()
}
}
// onProcessSkippedEvent is an event triggered on skipped machines, allowing handlers to
// extend lookahead window, in case where progress is not possible otherwise.
func (q *blocksQueue) onProcessSkippedEvent(ctx context.Context) eventHandlerFn {
return func(m *stateMachine, in interface{}) (stateID, error) {
if ctx.Err() != nil {
return m.state, ctx.Err()
}
if m.state != stateSkipped {
return m.state, errInvalidInitialState
}
// Only the highest epoch with skipped state can trigger extension.
if !m.isLast() {
// When a state machine stays in skipped state for too long - reset it.
if time.Since(m.updated) > skippedMachineTimeout {
return stateNew, nil
}
return m.state, nil
}
// Make sure that all machines are in skipped state i.e. manager cannot progress without reset or
// moving the last machine's start block forward (in an attempt to find next non-skipped block).
if !q.smm.allMachinesInState(stateSkipped) {
return m.state, nil
}
// Check if we have enough peers to progress, or sync needs to halt (due to no peers available).
bestFinalizedSlot := q.blocksFetcher.bestFinalizedSlot()
if q.mode == modeStopOnFinalizedEpoch {
if bestFinalizedSlot <= q.chain.HeadSlot() {
return stateSkipped, errNoRequiredPeers
}
} else {
if q.blocksFetcher.bestNonFinalizedSlot() <= q.chain.HeadSlot() {
return stateSkipped, errNoRequiredPeers
}
}
// All machines are skipped, FSMs need reset.
startSlot := q.chain.HeadSlot() + 1
if q.mode == modeNonConstrained && startSlot > bestFinalizedSlot {
q.staleEpochs[slots.ToEpoch(startSlot)]++
// If FSMs have been reset enough times, try to explore alternative forks.
if q.staleEpochs[slots.ToEpoch(startSlot)] >= maxResetAttempts {
delete(q.staleEpochs, slots.ToEpoch(startSlot))
fork, err := q.blocksFetcher.findFork(ctx, startSlot)
if err == nil {
return stateSkipped, q.resetFromFork(fork)
}
log.WithFields(logrus.Fields{
"epoch": slots.ToEpoch(startSlot),
"error": err.Error(),
}).Debug("Can not explore alternative branches")
}
}
return stateSkipped, q.resetFromSlot(ctx, startSlot)
}
}
// onCheckStaleEvent is an event that allows to mark stale epochs,
// so that they can be re-processed.
func (_ *blocksQueue) onCheckStaleEvent(ctx context.Context) eventHandlerFn {
return func(m *stateMachine, in interface{}) (stateID, error) {
if ctx.Err() != nil {
return m.state, ctx.Err()
}
if m.state != stateSent {
return m.state, errInvalidInitialState
}
// Break out immediately if bucket is not stale.
if time.Since(m.updated) < staleEpochTimeout {
return m.state, nil
}
return stateSkipped, nil
}
}