nimbus-eth2/beacon_chain/sync_manager.nim

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import chronicles
import options, deques, heapqueue, tables, strutils, sequtils, math, algorithm
import stew/results, chronos, chronicles
import spec/[datatypes, digest], peer_pool, eth2_network
import eth/async_utils
import ./eth2_processor
import block_pools/block_pools_types
export datatypes, digest, chronos, chronicles, results, block_pools_types
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logScope:
topics = "syncman"
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const
PeerScoreNoStatus* = -100
## Peer did not answer `status` request.
PeerScoreStaleStatus* = -50
## Peer's `status` answer do not progress in time.
PeerScoreGoodStatus* = 50
## Peer's `status` answer is fine.
PeerScoreNoBlocks* = -100
## Peer did not respond in time on `blocksByRange` request.
PeerScoreGoodBlocks* = 100
## Peer's `blocksByRange` answer is fine.
PeerScoreBadBlocks* = -1000
## Peer's response contains incorrect blocks.
PeerScoreBadResponse* = -1000
## Peer's response is not in requested range.
PeerScoreMissingBlocks* = -200
## Peer response contains too many empty blocks.
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type
SyncFailureKind* = enum
StatusInvalid,
StatusDownload,
StatusStale,
EmptyProblem,
BlockDownload,
BadResponse
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GetSlotCallback* = proc(): Slot {.gcsafe, raises: [Defect].}
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SyncRequest*[T] = object
index*: uint64
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slot*: Slot
count*: uint64
step*: uint64
item*: T
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SyncResult*[T] = object
request*: SyncRequest[T]
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data*: seq[SignedBeaconBlock]
SyncWaiter*[T] = object
future: Future[bool]
request: SyncRequest[T]
SyncQueue*[T] = ref object
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inpSlot*: Slot
outSlot*: Slot
startSlot*: Slot
lastSlot: Slot
chunkSize*: uint64
queueSize*: int
counter*: uint64
pending*: Table[uint64, SyncRequest[T]]
waiters: seq[SyncWaiter[T]]
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getFinalizedSlot*: GetSlotCallback
debtsQueue: HeapQueue[SyncRequest[T]]
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debtsCount: uint64
readyQueue: HeapQueue[SyncResult[T]]
suspects: seq[SyncResult[T]]
outQueue: AsyncQueue[BlockEntry]
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SyncManager*[A, B] = ref object
pool: PeerPool[A, B]
responseTimeout: chronos.Duration
sleepTime: chronos.Duration
maxWorkersCount: int
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maxStatusAge: uint64
maxHeadAge: uint64
maxRecurringFailures: int
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toleranceValue: uint64
getLocalHeadSlot: GetSlotCallback
getLocalWallSlot: GetSlotCallback
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getFinalizedSlot: GetSlotCallback
chunkSize: uint64
queue: SyncQueue[A]
failures: seq[SyncFailure[A]]
syncFut: Future[void]
outQueue: AsyncQueue[BlockEntry]
inProgress*: bool
SyncMoment* = object
stamp*: chronos.Moment
slot*: Slot
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SyncFailure*[T] = object
kind*: SyncFailureKind
peer*: T
stamp*: chronos.Moment
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SyncManagerError* = object of CatchableError
BeaconBlocksRes* = NetRes[seq[SignedBeaconBlock]]
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proc validate*[T](sq: SyncQueue[T],
blk: SignedBeaconBlock): Future[Result[void, BlockError]] {.async.} =
let sblock = SyncBlock(
blk: blk,
resfut: newFuture[Result[void, BlockError]]("sync.manager.validate")
)
await sq.outQueue.addLast(BlockEntry(v: sblock))
return await sblock.resfut
proc getShortMap*[T](req: SyncRequest[T],
data: openarray[SignedBeaconBlock]): string =
## Returns all slot numbers in ``data`` as placement map.
var res = newStringOfCap(req.count)
var slider = req.slot
var last = 0
for i in 0 ..< req.count:
if last < len(data):
for k in last ..< len(data):
if slider == data[k].message.slot:
res.add('x')
last = k + 1
break
elif slider < data[k].message.slot:
res.add('.')
break
else:
res.add('.')
slider = slider + req.step
result = res
proc contains*[T](req: SyncRequest[T], slot: Slot): bool {.inline.} =
slot >= req.slot and slot < req.slot + req.count * req.step and
((slot - req.slot) mod req.step == 0)
proc cmp*[T](a, b: SyncRequest[T]): int =
result = cmp(uint64(a.slot), uint64(b.slot))
proc checkResponse*[T](req: SyncRequest[T],
data: openarray[SignedBeaconBlock]): bool =
if len(data) == 0:
# Impossible to verify empty response.
return true
if uint64(len(data)) > req.count:
# Number of blocks in response should be less or equal to number of
# requested blocks.
return false
var slot = req.slot
var rindex = 0'u64
var dindex = 0
while (rindex < req.count) and (dindex < len(data)):
if slot < data[dindex].message.slot:
discard
elif slot == data[dindex].message.slot:
inc(dindex)
else:
return false
slot = slot + req.step
rindex = rindex + 1'u64
if dindex == len(data):
return true
else:
return false
proc getFullMap*[T](req: SyncRequest[T],
data: openarray[SignedBeaconBlock]): string =
# Returns all slot numbers in ``data`` as comma-delimeted string.
result = mapIt(data, $it.message.slot).join(", ")
proc init*[T](t1: typedesc[SyncRequest], t2: typedesc[T], slot: Slot,
count: uint64): SyncRequest[T] {.inline.} =
result = SyncRequest[T](slot: slot, count: count, step: 1'u64)
proc init*[T](t1: typedesc[SyncRequest], t2: typedesc[T], start: Slot,
finish: Slot): SyncRequest[T] {.inline.} =
let count = finish - start + 1'u64
result = SyncRequest[T](slot: start, count: count, step: 1'u64)
proc init*[T](t1: typedesc[SyncRequest], t2: typedesc[T], slot: Slot,
count: uint64, item: T): SyncRequest[T] {.inline.} =
result = SyncRequest[T](slot: slot, count: count, item: item, step: 1'u64)
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proc init*[T](t1: typedesc[SyncRequest], t2: typedesc[T], start: Slot,
finish: Slot, item: T): SyncRequest[T] {.inline.} =
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let count = finish - start + 1'u64
result = SyncRequest[T](slot: start, count: count, step: 1'u64, item: item)
proc init*[T](t1: typedesc[SyncFailure], kind: SyncFailureKind,
peer: T): SyncFailure[T] {.inline.} =
result = SyncFailure[T](kind: kind, peer: peer, stamp: now(chronos.Moment))
proc empty*[T](t: typedesc[SyncRequest],
t2: typedesc[T]): SyncRequest[T] {.inline.} =
result = SyncRequest[T](step: 0'u64, count: 0'u64)
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proc setItem*[T](sr: var SyncRequest[T], item: T) =
sr.item = item
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proc isEmpty*[T](sr: SyncRequest[T]): bool {.inline.} =
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result = (sr.step == 0'u64) and (sr.count == 0'u64)
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proc init*[T](t1: typedesc[SyncQueue], t2: typedesc[T],
start, last: Slot, chunkSize: uint64,
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getFinalizedSlotCb: GetSlotCallback,
outputQueue: AsyncQueue[BlockEntry],
queueSize: int = -1): SyncQueue[T] =
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## Create new synchronization queue with parameters
##
## ``start`` and ``last`` are starting and finishing Slots.
##
## ``chunkSize`` maximum number of slots in one request.
##
## ``queueSize`` maximum queue size for incoming data. If ``queueSize > 0``
## queue will help to keep backpressure under control. If ``queueSize <= 0``
## then queue size is unlimited (default).
##
## ``updateCb`` procedure which will be used to send downloaded blocks to
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## consumer. Procedure should return ``false`` only when it receives
## incorrect blocks, and ``true`` if sequence of blocks is correct.
# SyncQueue is the core of sync manager, this data structure distributes
# requests to peers and manages responses from peers.
#
# Because SyncQueue is async data structure it manages backpressure and
# order of incoming responses and it also resolves "joker's" problem.
#
# Joker's problem
#
# According to current Ethereum2 network specification
# > Clients MUST respond with at least one block, if they have it and it
# > exists in the range. Clients MAY limit the number of blocks in the
# > response.
#
# Such rule can lead to very uncertain responses, for example let slots from
# 10 to 12 will be not empty. Client which follows specification can answer
# with any response from this list (X - block, `-` empty space):
#
# 1. X X X
# 2. - - X
# 3. - X -
# 4. - X X
# 5. X - -
# 6. X - X
# 7. X X -
#
# If peer answers with `1` everything will be fine and `block_pool` will be
# able to process all 3 blocks. In case of `2`, `3`, `4`, `6` - `block_pool`
# will fail immediately with chunk and report "parent is missing" error.
# But in case of `5` and `7` blocks will be processed by `block_pool` without
# any problems, however it will start producing problems right from this
# uncertain last slot. SyncQueue will start producing requests for next
# blocks, but all the responses from this point will fail with "parent is
# missing" error. Lets call such peers "jokers", because they are joking
# with responses.
#
# To fix "joker" problem we going to perform rollback to the latest finalized
# epoch's first slot.
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doAssert(chunkSize > 0'u64, "Chunk size should not be zero")
result = SyncQueue[T](
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startSlot: start,
lastSlot: last,
chunkSize: chunkSize,
queueSize: queueSize,
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getFinalizedSlot: getFinalizedSlotCb,
waiters: newSeq[SyncWaiter[T]](),
counter: 1'u64,
pending: initTable[uint64, SyncRequest[T]](),
debtsQueue: initHeapQueue[SyncRequest[T]](),
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inpSlot: start,
outSlot: start,
outQueue: outputQueue
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)
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proc `<`*[T](a, b: SyncRequest[T]): bool {.inline.} =
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result = (a.slot < b.slot)
proc `<`*[T](a, b: SyncResult[T]): bool {.inline.} =
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result = (a.request.slot < b.request.slot)
proc `==`*[T](a, b: SyncRequest[T]): bool {.inline.} =
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result = ((a.slot == b.slot) and (a.count == b.count) and
(a.step == b.step))
proc lastSlot*[T](req: SyncRequest[T]): Slot {.inline.} =
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## Returns last slot for request ``req``.
result = req.slot + req.count - 1'u64
proc makePending*[T](sq: SyncQueue[T], req: var SyncRequest[T]) =
req.index = sq.counter
sq.counter = sq.counter + 1'u64
sq.pending[req.index] = req
proc updateLastSlot*[T](sq: SyncQueue[T], last: Slot) {.inline.} =
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## Update last slot stored in queue ``sq`` with value ``last``.
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doAssert(sq.lastSlot <= last,
"Last slot could not be lower then stored one " &
$sq.lastSlot & " <= " & $last)
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sq.lastSlot = last
proc wakeupWaiters[T](sq: SyncQueue[T], flag = true) {.inline.} =
## Wakeup one or all blocked waiters.
for item in sq.waiters:
if not(item.future.finished()):
item.future.complete(flag)
proc waitForChanges[T](sq: SyncQueue[T],
req: SyncRequest[T]): Future[bool] {.async.} =
## Create new waiter and wait for completion from `wakeupWaiters()`.
var waitfut = newFuture[bool]("SyncQueue.waitForChanges")
let waititem = SyncWaiter[T](future: waitfut, request: req)
sq.waiters.add(waititem)
try:
result = await waitfut
finally:
sq.waiters.delete(sq.waiters.find(waititem))
proc wakeupAndWaitWaiters[T](sq: SyncQueue[T]) {.async.} =
## This procedure will perform wakeupWaiters(false) and blocks until last
## waiter will be awakened.
var waitChanges = sq.waitForChanges(SyncRequest.empty(T))
sq.wakeupWaiters(false)
discard await waitChanges
proc resetWait*[T](sq: SyncQueue[T], toSlot: Option[Slot]) {.async.} =
## Perform reset of all the blocked waiters in SyncQueue.
##
## We adding one more waiter to the waiters sequence and
## call wakeupWaiters(false). Because our waiter is last in sequence of
## waiters it will be resumed only after all waiters will be awakened and
## finished.
# We are clearing pending list, so that all requests that are still running
# around (still downloading, but not yet pushed to the SyncQueue) will be
# expired. Its important to perform this call first (before await), otherwise
# you can introduce race problem.
sq.pending.clear()
# We calculating minimal slot number to which we will be able to reset,
# without missing any blocks. There 3 sources:
# 1. Debts queue.
# 2. Processing queue (`inpSlot`, `outSlot`).
# 3. Requested slot `toSlot`.
#
# Queue's `outSlot` is the lowest slot we added to `block_pool`, but
# `toSlot` slot can be less then `outSlot`. `debtsQueue` holds only not
# added slot requests, so it can't be bigger then `outSlot` value.
var minSlot = sq.outSlot
if toSlot.isSome():
minSlot = min(toSlot.get(), sq.outSlot)
sq.debtsQueue.clear()
sq.debtsCount = 0
sq.readyQueue.clear()
sq.inpSlot = minSlot
sq.outSlot = minSlot
# We are going to wakeup all the waiters and wait for last one.
await sq.wakeupAndWaitWaiters()
proc isEmpty*[T](sr: SyncResult[T]): bool {.inline.} =
## Returns ``true`` if response chain of blocks is empty (has only empty
## slots).
len(sr.data) == 0
proc hasEndGap*[T](sr: SyncResult[T]): bool {.inline.} =
## Returns ``true`` if response chain of blocks has gap at the end.
let lastslot = sr.request.slot + sr.request.count - 1'u64
if len(sr.data) == 0:
return true
if sr.data[^1].message.slot != lastslot:
return true
return false
proc getLastNonEmptySlot*[T](sr: SyncResult[T]): Slot {.inline.} =
## Returns last non-empty slot from result ``sr``. If response has only
## empty slots, original request slot will be returned.
if len(sr.data) == 0:
# If response has only empty slots we going to use original request slot
sr.request.slot
else:
sr.data[^1].message.slot
proc toDebtsQueue[T](sq: SyncQueue[T], sr: SyncRequest[T]) {.inline.} =
sq.debtsQueue.push(sr)
sq.debtsCount = sq.debtsCount + sr.count
proc push*[T](sq: SyncQueue[T], sr: SyncRequest[T],
data: seq[SignedBeaconBlock]) {.async, gcsafe.} =
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## Push successfull result to queue ``sq``.
mixin updateScore
if sr.index notin sq.pending:
# If request `sr` not in our pending list, it only means that
# SyncQueue.resetWait() happens and all pending requests are expired, so
# we swallow `old` requests, and in such way sync-workers are able to get
# proper new requests from SyncQueue.
return
sq.pending.del(sr.index)
# This is backpressure handling algorithm, this algorithm is blocking
# all pending `push` requests if `request.slot` not in range:
# [current_queue_slot, current_queue_slot + sq.queueSize * sq.chunkSize].
var exitNow = false
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while true:
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if (sq.queueSize > 0) and
(sr.slot >= sq.outSlot + uint64(sq.queueSize) * sq.chunkSize):
let res = await sq.waitForChanges(sr)
if res:
continue
else:
# SyncQueue reset happens. We are exiting to wake up sync-worker.
exitNow = true
break
let syncres = SyncResult[T](request: sr, data: data)
sq.readyQueue.push(syncres)
exitNow = false
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break
if exitNow:
return
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while len(sq.readyQueue) > 0:
let minSlot = sq.readyQueue[0].request.slot
if sq.outSlot != minSlot:
break
let item = sq.readyQueue.pop()
# Validating received blocks one by one
var res: Result[void, BlockError]
if len(item.data) > 0:
for blk in item.data:
trace "Pushing block", block_root = blk.root,
block_slot = blk.message.slot
res = await sq.validate(blk)
if not(res.isOk):
break
else:
res = Result[void, BlockError].ok()
if res.isOk:
sq.outSlot = sq.outSlot + item.request.count
sq.wakeupWaiters()
else:
debug "Block pool rejected peer's response", peer = item.request.item,
request_slot = item.request.slot,
request_count = item.request.count,
request_step = item.request.step,
blocks_map = getShortMap(item.request, item.data),
blocks_count = len(item.data), errCode = res.error,
topics = "syncman"
var resetSlot: Option[Slot]
if res.error == BlockError.MissingParent:
# If we got `BlockError.MissingParent` it means that peer returns chain
# of blocks with holes or `block_pool` is in incomplete state. We going
# to rewind to the first slot at latest finalized epoch.
let req = item.request
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let finalizedSlot = sq.getFinalizedSlot()
if finalizedSlot < req.slot:
warn "Unexpected missing parent, rewind happens",
peer = req.item, rewind_to_slot = finalizedSlot,
request_slot = req.slot, request_count = req.count,
request_step = req.step, blocks_count = len(item.data),
blocks_map = getShortMap(req, item.data), topics = "syncman"
resetSlot = some(finalizedSlot)
req.item.updateScore(PeerScoreMissingBlocks)
else:
error "Unexpected missing parent at finalized epoch slot",
peer = req.item, to_slot = finalizedSlot,
request_slot = req.slot, request_count = req.count,
request_step = req.step, blocks_count = len(item.data),
blocks_map = getShortMap(req, item.data), topics = "syncman"
req.item.updateScore(PeerScoreBadBlocks)
elif res.error == BlockError.Invalid:
let req = item.request
warn "Received invalid sequence of blocks", peer = req.item,
request_slot = req.slot, request_count = req.count,
request_step = req.step, blocks_count = len(item.data),
blocks_map = getShortMap(req, item.data), topics = "syncman"
req.item.updateScore(PeerScoreBadBlocks)
else:
let req = item.request
warn "Received unexpected response from block_pool", peer = req.item,
request_slot = req.slot, request_count = req.count,
request_step = req.step, blocks_count = len(item.data),
blocks_map = getShortMap(req, item.data), errorCode = res.error,
topics = "syncman"
req.item.updateScore(PeerScoreBadBlocks)
# We need to move failed response to the debts queue.
sq.toDebtsQueue(item.request)
if resetSlot.isSome():
await sq.resetWait(resetSlot)
debug "Rewind to slot was happened", reset_slot = reset_slot.get(),
queue_input_slot = sq.inpSlot,
queue_output_slot = sq.outSlot,
topics = "syncman"
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break
proc push*[T](sq: SyncQueue[T], sr: SyncRequest[T]) =
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## Push failed request back to queue.
if sr.index notin sq.pending:
# If request `sr` not in our pending list, it only means that
# SyncQueue.resetWait() happens and all pending requests are expired, so
# we swallow `old` requests, and in such way sync-workers are able to get
# proper new requests from SyncQueue.
return
sq.pending.del(sr.index)
sq.toDebtsQueue(sr)
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proc pop*[T](sq: SyncQueue[T], maxslot: Slot, item: T): SyncRequest[T] =
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if len(sq.debtsQueue) > 0:
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if maxSlot < sq.debtsQueue[0].slot:
return SyncRequest.empty(T)
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var sr = sq.debtsQueue.pop()
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if sr.lastSlot() <= maxSlot:
sq.debtsCount = sq.debtsCount - sr.count
sr.setItem(item)
sq.makePending(sr)
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return sr
var sr1 = SyncRequest.init(T, sr.slot, maxslot, item)
let sr2 = SyncRequest.init(T, maxslot + 1'u64, sr.lastSlot())
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sq.debtsQueue.push(sr2)
sq.debtsCount = sq.debtsCount - sr1.count
sq.makePending(sr1)
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return sr1
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else:
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if maxSlot < sq.inpSlot:
return SyncRequest.empty(T)
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if sq.inpSlot > sq.lastSlot:
return SyncRequest.empty(T)
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let lastSlot = min(maxslot, sq.lastSlot)
let count = min(sq.chunkSize, lastSlot + 1'u64 - sq.inpSlot)
var sr = SyncRequest.init(T, sq.inpSlot, count, item)
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sq.inpSlot = sq.inpSlot + count
sq.makePending(sr)
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return sr
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proc len*[T](sq: SyncQueue[T]): uint64 {.inline.} =
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## Returns number of slots left in queue ``sq``.
if sq.inpSlot > sq.lastSlot:
result = sq.debtsCount
else:
result = sq.lastSlot - sq.inpSlot + 1'u64 - sq.debtsCount
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proc total*[T](sq: SyncQueue[T]): uint64 {.inline.} =
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## Returns total number of slots in queue ``sq``.
result = sq.lastSlot - sq.startSlot + 1'u64
proc progress*[T](sq: SyncQueue[T]): uint64 =
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## Returns queue's ``sq`` progress string.
let curSlot = sq.outSlot - sq.startSlot
result = (curSlot * 100'u64) div sq.total()
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proc now*(sm: typedesc[SyncMoment], slot: Slot): SyncMoment {.inline.} =
result = SyncMoment(stamp: now(chronos.Moment), slot: slot)
proc speed*(start, finish: SyncMoment): float {.inline.} =
## Returns number of slots per second.
let slots = finish.slot - start.slot
let dur = finish.stamp - start.stamp
let secs = float(chronos.seconds(1).nanoseconds)
if isZero(dur):
result = 0.0
else:
let v = float(slots) * (secs / float(dur.nanoseconds))
# We doing round manually because stdlib.round is deprecated
result = round(v * 10000) / 10000
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proc newSyncManager*[A, B](pool: PeerPool[A, B],
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getLocalHeadSlotCb: GetSlotCallback,
getLocalWallSlotCb: GetSlotCallback,
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getFinalizedSlotCb: GetSlotCallback,
outputQueue: AsyncQueue[BlockEntry],
maxWorkers = 10,
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maxStatusAge = uint64(SLOTS_PER_EPOCH * 4),
maxHeadAge = uint64(SLOTS_PER_EPOCH * 1),
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sleepTime = (int(SLOTS_PER_EPOCH) *
int(SECONDS_PER_SLOT)).seconds,
chunkSize = uint64(SLOTS_PER_EPOCH),
toleranceValue = uint64(1),
maxRecurringFailures = 3
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): SyncManager[A, B] =
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let queue = SyncQueue.init(A, getFinalizedSlotCb(), getLocalWallSlotCb(),
chunkSize, getFinalizedSlotCb, outputQueue, 1)
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result = SyncManager[A, B](
pool: pool,
maxWorkersCount: maxWorkers,
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maxStatusAge: maxStatusAge,
getLocalHeadSlot: getLocalHeadSlotCb,
getLocalWallSlot: getLocalWallSlotCb,
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getFinalizedSlot: getFinalizedSlotCb,
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maxHeadAge: maxHeadAge,
maxRecurringFailures: maxRecurringFailures,
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sleepTime: sleepTime,
chunkSize: chunkSize,
queue: queue,
outQueue: outputQueue
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)
proc getBlocks*[A, B](man: SyncManager[A, B], peer: A,
req: SyncRequest): Future[BeaconBlocksRes] {.async.} =
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mixin beaconBlocksByRange, getScore, `==`
doAssert(not(req.isEmpty()), "Request must not be empty!")
debug "Requesting blocks from peer", peer = peer,
slot = req.slot, slot_count = req.count, step = req.step,
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peer_score = peer.getScore(), peer_speed = peer.netKbps(),
topics = "syncman"
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var workFut = awaitne beaconBlocksByRange(peer, req.slot, req.count, req.step)
if workFut.failed():
debug "Error, while waiting getBlocks response", peer = peer,
slot = req.slot, slot_count = req.count, step = req.step,
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errMsg = workFut.readError().msg, peer_speed = peer.netKbps(),
topics = "syncman"
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else:
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let res = workFut.read()
if res.isErr:
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debug "Error, while reading getBlocks response",
peer = peer, slot = req.slot, count = req.count,
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step = req.step, peer_speed = peer.netKbps(),
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topics = "syncman", error = res.error()
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result = res
template headAge(): uint64 =
wallSlot - headSlot
template peerAge(): uint64 =
if peerSlot > wallSlot: 0'u64 else: wallSlot - peerSlot
template checkPeerScore(peer, body: untyped): untyped =
mixin getScore
let currentScore = peer.getScore()
body
let newScore = peer.getScore()
if currentScore > newScore:
debug "Overdue penalty for peer's score received, exiting", peer = peer,
penalty = newScore - currentScore, peer_score = newScore,
topics = "syncman"
break
func syncQueueLen*[A, B](man: SyncManager[A, B]): uint64 =
man.queue.len
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proc syncWorker*[A, B](man: SyncManager[A, B],
peer: A): Future[A] {.async.} =
# Sync worker is the lowest level loop which performs syncing with single
# peer.
#
# Logic here is pretty simple:
# 1. Obtain request from SyncQueue.
# 2. Send this request to a peer and obtain response.
# 3. Push response to the SyncQueue, (doesn't matter if it success or failure)
# 4. Update main SyncQueue last slot with wall time slot number.
# 5. From time to time we also requesting peer's status information.
# 6. If our current head slot is near equal to peer's head slot we are
# exiting this loop and finishing that sync-worker task.
# 7. Repeat
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mixin getKey, getScore, getHeadSlot
debug "Starting syncing with peer", peer = peer,
peer_score = peer.getScore(),
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peer_speed = peer.netKbps(),
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topics = "syncman"
try:
while true:
var wallSlot = man.getLocalWallSlot()
var headSlot = man.getLocalHeadSlot()
var peerSlot = peer.getHeadSlot()
man.queue.updateLastSlot(wallSlot)
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debug "Peer's syncing status", wall_clock_slot = wallSlot,
remote_head_slot = peerSlot, local_head_slot = headSlot,
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peer_score = peer.getScore(), peer = peer,
peer_speed = peer.netKbps(), topics = "syncman"
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if peerSlot > wallSlot + man.toleranceValue:
# Our wall timer is broken, or peer's status information is invalid.
debug "Local timer is broken or peer's status information is invalid",
wall_clock_slot = wallSlot, remote_head_slot = peerSlot,
local_head_slot = headSlot, peer = peer,
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tolerance_value = man.toleranceValue, peer_speed = peer.netKbps(),
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peer_score = peer.getScore(), topics = "syncman"
let failure = SyncFailure.init(SyncFailureKind.StatusInvalid, peer)
man.failures.add(failure)
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break
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if peerAge >= man.maxStatusAge:
# Peer's status information is very old, we going to update it.
debug "Updating peer's status information", wall_clock_slot = wallSlot,
remote_head_slot = peerSlot, local_head_slot = headSlot,
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peer = peer, peer_score = peer.getScore(),
peer_speed = peer.netKbps(), topics = "syncman"
checkPeerScore peer:
let res = await peer.updateStatus()
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if not(res):
peer.updateScore(PeerScoreNoStatus)
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debug "Failed to get remote peer's status, exiting", peer = peer,
peer_score = peer.getScore(), peer_head_slot = peerSlot,
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peer_speed = peer.netKbps(), topics = "syncman"
let failure = SyncFailure.init(SyncFailureKind.StatusDownload, peer)
man.failures.add(failure)
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break
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let newPeerSlot = peer.getHeadSlot()
if peerSlot >= newPeerSlot:
peer.updateScore(PeerScoreStaleStatus)
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debug "Peer's status information is stale, exiting",
wall_clock_slot = wallSlot, remote_old_head_slot = peerSlot,
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local_head_slot = headSlot, remote_new_head_slot = newPeerSlot,
peer = peer, peer_score = peer.getScore(),
peer_speed = peer.netKbps(), topics = "syncman"
let failure = SyncFailure.init(SyncFailureKind.StatusStale, peer)
man.failures.add(failure)
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break
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debug "Peer's status information updated", wall_clock_slot = wallSlot,
remote_old_head_slot = peerSlot, local_head_slot = headSlot,
remote_new_head_slot = newPeerSlot, peer = peer,
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peer_score = peer.getScore(), peer_speed = peer.netKbps(),
topics = "syncman"
peer.updateScore(PeerScoreGoodStatus)
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peerSlot = newPeerSlot
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if (peerAge <= man.maxHeadAge) and (headAge <= man.maxHeadAge):
debug "We are in sync with peer, exiting", wall_clock_slot = wallSlot,
remote_head_slot = peerSlot, local_head_slot = headSlot,
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peer = peer, peer_score = peer.getScore(),
peer_speed = peer.netKbps(), topics = "syncman"
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break
let req = man.queue.pop(peerSlot, peer)
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if req.isEmpty():
debug "Empty request received from queue, exiting", peer = peer,
local_head_slot = headSlot, remote_head_slot = peerSlot,
queue_input_slot = man.queue.inpSlot,
queue_output_slot = man.queue.outSlot,
queue_last_slot = man.queue.lastSlot,
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peer_speed = peer.netKbps(), peer_score = peer.getScore(),
topics = "syncman"
# Sometimes when syncing is almost done but last requests are still
# pending, this can fall into endless cycle, when low number of peers
# are available in PeerPool. We going to wait for RESP_TIMEOUT time,
# so all pending requests should be finished at this moment.
checkPeerScore peer:
await sleepAsync(RESP_TIMEOUT)
let failure = SyncFailure.init(SyncFailureKind.EmptyProblem, peer)
man.failures.add(failure)
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break
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debug "Creating new request for peer", wall_clock_slot = wallSlot,
remote_head_slot = peerSlot, local_head_slot = headSlot,
request_slot = req.slot, request_count = req.count,
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request_step = req.step, peer = peer, peer_speed = peer.netKbps(),
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peer_score = peer.getScore(), topics = "syncman"
checkPeerScore peer:
let blocks = await man.getBlocks(peer, req)
if blocks.isOk:
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let data = blocks.get()
let smap = getShortMap(req, data)
debug "Received blocks on request", blocks_count = len(data),
blocks_map = smap, request_slot = req.slot,
request_count = req.count, request_step = req.step,
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peer = peer, peer_score = peer.getScore(),
peer_speed = peer.netKbps(), topics = "syncman"
if not(checkResponse(req, data)):
peer.updateScore(PeerScoreBadResponse)
warn "Received blocks sequence is not in requested range",
blocks_count = len(data), blocks_map = smap,
request_slot = req.slot, request_count = req.count,
request_step = req.step, peer = peer,
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peer_score = peer.getScore(), peer_speed = peer.netKbps(),
topics = "syncman"
let failure = SyncFailure.init(SyncFailureKind.BadResponse, peer)
man.failures.add(failure)
break
# Scoring will happen in `syncUpdate`.
checkPeerScore peer,
await man.queue.push(req, data)
# Cleaning up failures.
man.failures.setLen(0)
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else:
peer.updateScore(PeerScoreNoBlocks)
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man.queue.push(req)
debug "Failed to receive blocks on request",
request_slot = req.slot, request_count = req.count,
request_step = req.step, peer = peer,
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peer_score = peer.getScore(), peer_speed = peer.netKbps(),
topics = "syncman"
let failure = SyncFailure.init(SyncFailureKind.BlockDownload, peer)
man.failures.add(failure)
break
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result = peer
finally:
man.pool.release(peer)
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proc syncLoop[A, B](man: SyncManager[A, B]) {.async.} =
# This procedure manages main loop of SyncManager and in this loop it
# performs
# 1. It checks for current sync status, "are we synced?".
# 2. If we are in active syncing, it tries to acquire new peers from PeerPool
# and spawns new sync-workers. Number of spawned sync-workers can be
# controlled by `maxWorkersCount` value.
# 3. It stops spawning sync-workers when we are "in sync".
# 4. It calculates syncing performance.
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mixin getKey, getScore
var pending = newSeq[Future[A]]()
var acquireFut: Future[A]
var syncSpeed: float = 0.0
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template workersCount(): int =
if isNil(acquireFut): len(pending) else: (len(pending) - 1)
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proc watchTask() {.async.} =
while true:
let lsm1 = SyncMoment.now(man.getLocalHeadSlot())
await sleepAsync(chronos.seconds(int(SECONDS_PER_SLOT)))
let lsm2 = SyncMoment.now(man.getLocalHeadSlot())
if workersCount() == 0:
syncSpeed = 0.0
else:
if (lsm2.slot - lsm1.slot == 0'u64) and (workersCount() > 1):
debug "Syncing process is not progressing, reset the queue",
workers_count = workersCount(),
to_slot = man.queue.outSlot,
local_head_slot = lsm1.slot, topics = "syncman"
await man.queue.resetWait(none[Slot]())
else:
syncSpeed = speed(lsm1, lsm2)
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debug "Synchronization loop started", topics = "syncman"
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traceAsyncErrors watchTask()
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while true:
let wallSlot = man.getLocalWallSlot()
let headSlot = man.getLocalHeadSlot()
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let progress =
if headSlot <= man.queue.lastSlot:
man.queue.progress()
else:
100'u64
debug "Synchronization loop tick", wall_head_slot = wallSlot,
local_head_slot = headSlot, queue_status = progress,
queue_start_slot = man.queue.startSlot,
queue_last_slot = man.queue.lastSlot,
waiting_for_new_peer = $not(isNil(acquireFut)),
sync_speed = syncSpeed, workers_count = workersCount(),
topics = "syncman"
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var temp = newSeqOfCap[Future[A]](len(pending))
for fut in pending:
if fut.finished():
if fut == acquireFut:
# We acquired new peer from PeerPool.
if acquireFut.failed():
debug "Synchronization loop failed to get new peer",
wall_head_slot = wallSlot, local_head_slot = headSlot,
workers_count = workersCount(),
errMsg = acquireFut.readError().msg, topics = "syncman"
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else:
let peer = acquireFut.read()
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if headAge <= man.maxHeadAge:
# If we are already in sync, we going to release just acquired
# peer and do not acquire peers
debug "Synchronization loop reached sync barrier", peer = peer,
wall_head_slot = wallSlot, local_head_slot = headSlot,
peer_score = peer.getScore(), topics = "syncman"
man.pool.release(peer)
else:
if headSlot > man.queue.lastSlot:
debug "Synchronization lost, restoring",
wall_head_slot = wallSlot, local_head_slot = headSlot,
queue_last_slot = man.queue.lastSlot, topics = "syncman"
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man.queue = SyncQueue.init(A, man.getFinalizedSlot(), wallSlot,
man.chunkSize, man.getFinalizedSlot,
man.outQueue, 1)
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debug "Synchronization loop starting new worker", peer = peer,
wall_head_slot = wallSlot, local_head_slot = headSlot,
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peer_score = peer.getScore(), peer_speed = peer.netKbps(),
topics = "syncman"
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temp.add(syncWorker(man, peer))
# We will create new `acquireFut` later.
acquireFut = nil
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else:
# We got worker finished its work
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if fut.failed():
debug "Synchronization loop got worker finished with an error",
wall_head_slot = wallSlot, local_head_slot = headSlot,
errMsg = fut.readError().msg, topics = "syncman"
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else:
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let peer = fut.read()
debug "Synchronization loop got worker finished",
wall_head_slot = wallSlot, local_head_slot = headSlot,
peer = peer, peer_score = peer.getScore(),
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peer_speed = peer.netKbps(),
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topics = "syncman"
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else:
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if fut == acquireFut:
# Task which waits for new peer from PeerPool is not yet finished.
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if headAge <= man.maxHeadAge:
debug "Synchronization loop reached sync barrier",
wall_head_slot = wallSlot, local_head_slot = headSlot,
topics = "syncman"
acquireFut = nil
fut.cancel()
else:
temp.add(fut)
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else:
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temp.add(fut)
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pending = temp
if headAge <= man.maxHeadAge:
debug "Synchronization loop sleeping", wall_head_slot = wallSlot,
local_head_slot = headSlot, workers_count = workersCount(),
difference = (wallSlot - headSlot),
max_head_age = man.maxHeadAge, topics = "syncman"
if len(pending) == 0:
man.inProgress = false
await sleepAsync(man.sleepTime)
else:
debug "Synchronization loop waiting for workers completion",
workers_count = workersCount(), topics = "syncman"
discard await withTimeout(one(pending), man.sleepTime)
else:
man.inProgress = true
if isNil(acquireFut) and len(pending) < man.maxWorkersCount:
acquireFut = man.pool.acquire()
pending.add(acquireFut)
debug "Synchronization loop waiting for new peer",
wall_head_slot = wallSlot, local_head_slot = headSlot,
workers_count = workersCount(), topics = "syncman",
sleep_time = $man.sleepTime
else:
debug "Synchronization loop waiting for workers",
wall_head_slot = wallSlot, local_head_slot = headSlot,
workers_count = workersCount(), topics = "syncman",
sleep_time = $man.sleep_time
discard await withTimeout(one(pending), man.sleepTime)
if len(man.failures) > man.maxRecurringFailures and (workersCount() > 1):
debug "Number of recurring failures exceeds limit, reseting queue",
workers_count = workers_count(), rec_failures = len(man.failures)
# Cleaning up failures.
man.failures.setLen(0)
await man.queue.resetWait(none[Slot]())
proc start*[A, B](man: SyncManager[A, B]) =
## Starts SyncManager's main loop.
man.syncFut = man.syncLoop()