nim-dagger/dagger/blockexchange/engine.nim

443 lines
12 KiB
Nim

## Nim-Dagger
## Copyright (c) 2021 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import std/sequtils
import pkg/chronos
import pkg/chronicles
import pkg/libp2p
import ../stores/blockstore
import ../blocktype as bt
import ../utils/asyncheapqueue
import ./protobuf/blockexc
import ./protobuf/presence
import ./network
import ./pendingblocks
import ./peercontext
import ./engine/payments
export peercontext, payments, pendingblocks
logScope:
topics = "dagger blockexc engine"
const
DefaultBlockTimeout* = 5.minutes
DefaultMaxPeersPerRequest* = 10
DefaultTaskQueueSize = 100
DefaultConcurrentTasks = 10
DefaultMaxRetries = 3
type
TaskHandler* = proc(task: BlockExcPeerCtx): Future[void] {.gcsafe.}
TaskScheduler* = proc(task: BlockExcPeerCtx): bool {.gcsafe.}
BlockExcEngine* = ref object of RootObj
localStore*: BlockStore # where we localStore blocks for this instance
network*: BlockExcNetwork # network interface
peers*: seq[BlockExcPeerCtx] # peers we're currently actively exchanging with
wantList*: seq[Cid] # local wants list
taskQueue*: AsyncHeapQueue[BlockExcPeerCtx] # peers we're currently processing tasks for
concurrentTasks: int # number of concurrent peers we're serving at any given time
maxRetries: int # max number of tries for a failed block
blockexcTasks: seq[Future[void]] # future to control blockexc task
blockexcRunning: bool # indicates if the blockexc task is running
pendingBlocks*: PendingBlocksManager # blocks we're awaiting to be resolved
peersPerRequest: int # max number of peers to request from
wallet*: WalletRef # nitro wallet for micropayments
pricing*: ?Pricing # optional bandwidth pricing
Pricing* = object
address*: EthAddress
price*: UInt256
proc contains*(a: AsyncHeapQueue[Entry], b: Cid): bool =
## Convenience method to check for entry prepense
##
a.anyIt( it.cid == b )
proc getPeerCtx*(b: BlockExcEngine, peerId: PeerID): BlockExcPeerCtx =
## Get the peer's context
##
let peer = b.peers.filterIt( it.id == peerId )
if peer.len > 0:
return peer[0]
# attach task scheduler to engine
proc scheduleTask(b: BlockExcEngine, task: BlockExcPeerCtx): bool {.gcsafe} =
b.taskQueue.pushOrUpdateNoWait(task).isOk()
proc blockexcTaskRunner(b: BlockExcEngine): Future[void] {.gcsafe.}
proc start*(b: BlockExcEngine) {.async.} =
## Start the blockexc task
##
trace "blockexc start"
if b.blockexcRunning:
warn "Starting blockexc twice"
return
b.blockexcRunning = true
for i in 0..<b.concurrentTasks:
b.blockexcTasks.add(blockexcTaskRunner(b))
proc stop*(b: BlockExcEngine) {.async.} =
## Stop the blockexc blockexc
##
trace "NetworkStore stop"
if not b.blockexcRunning:
warn "Stopping blockexc without starting it"
return
b.blockexcRunning = false
for t in b.blockexcTasks:
if not t.finished:
trace "Awaiting task to stop"
await t.cancelAndWait()
trace "Task stopped"
trace "NetworkStore stopped"
proc requestBlock*(
b: BlockExcEngine,
cid: Cid,
timeout = DefaultBlockTimeout): Future[bt.Block] =
## Request a block from remotes
##
let
blk = b.pendingBlocks.addOrAwait(cid).wait(timeout)
if b.peers.len <= 0:
warn "No peers to request blocks from"
# TODO: run discovery here to get peers for the block
return blk
var peers = b.peers
# get the first peer with at least one (any)
# matching cid
var blockPeer: BlockExcPeerCtx
for i, p in peers:
if cid in p.peerHave:
blockPeer = p
break
# didn't find any peer with matching cids
# use the first one in the sorted array
if isNil(blockPeer):
blockPeer = peers[0]
peers.keepItIf(
it != blockPeer
)
trace "Requesting block from peer", peer = blockPeer.id, cid
# request block
b.network.request.sendWantList(
blockPeer.id,
@[cid],
wantType = WantType.wantBlock) # we want this remote to send us a block
if peers.len == 0:
return blk # no peers to send wants to
# filter out the peer we've already requested from
let stop = min(peers.high, b.peersPerRequest)
trace "Sending want list requests to remaining peers", count = stop + 1
for p in peers[0..stop]:
if cid notin p.peerHave:
# just send wants
b.network.request.sendWantList(
p.id,
@[cid],
wantType = WantType.wantHave) # we only want to know if the peer has the block
return blk
proc blockPresenceHandler*(
b: BlockExcEngine,
peer: PeerID,
blocks: seq[BlockPresence]) {.async.} =
## Handle block presence
##
let peerCtx = b.getPeerCtx(peer)
if isNil(peerCtx):
return
for blk in blocks:
if presence =? Presence.init(blk):
peerCtx.updatePresence(presence)
proc scheduleTasks(b: BlockExcEngine, blocks: seq[bt.Block]) =
trace "Schedule a task for new blocks"
let cids = blocks.mapIt( it.cid )
# schedule any new peers to provide blocks to
for p in b.peers:
for c in cids: # for each cid
# schedule a peer if it wants at least one
# cid and we have it in our local store
if c in p.peerWants and c in b.localStore:
if not b.scheduleTask(p):
trace "Unable to schedule task for peer", peer = p.id
break # do next peer
proc resolveBlocks*(b: BlockExcEngine, blocks: seq[bt.Block]) =
## Resolve pending blocks from the pending blocks manager
## and schedule any new task to be ran
##
trace "Resolving blocks"
b.pendingBlocks.resolve(blocks)
b.scheduleTasks(blocks)
proc payForBlocks(engine: BlockExcEngine,
peer: BlockExcPeerCtx,
blocks: seq[bt.Block]) =
let sendPayment = engine.network.request.sendPayment
if sendPayment.isNil:
return
let cids = blocks.mapIt(it.cid)
if payment =? engine.wallet.pay(peer, peer.price(cids)):
sendPayment(peer.id, payment)
proc blocksHandler*(
b: BlockExcEngine,
peer: PeerID,
blocks: seq[bt.Block]) {.async.} =
## handle incoming blocks
##
trace "Got blocks from peer", peer, len = blocks.len
for blk in blocks:
if not (await b.localStore.putBlock(blk)):
trace "Unable to store block", cid = blk.cid
continue
b.resolveBlocks(blocks)
let peerCtx = b.getPeerCtx(peer)
if peerCtx != nil:
b.payForBlocks(peerCtx, blocks)
proc wantListHandler*(
b: BlockExcEngine,
peer: PeerID,
wantList: WantList) {.async.} =
## Handle incoming want lists
##
trace "Got want list for peer", peer
let peerCtx = b.getPeerCtx(peer)
if isNil(peerCtx):
return
var dontHaves: seq[Cid]
let entries = wantList.entries
for e in entries:
let idx = peerCtx.peerWants.find(e)
if idx > -1:
# peer doesn't want this block anymore
if e.cancel:
peerCtx.peerWants.del(idx)
continue
peerCtx.peerWants[idx] = e # update entry
else:
peerCtx.peerWants.add(e)
trace "Added entry to peer's want list", peer = peerCtx.id, cid = $e.cid
# peer might want to ask for the same cid with
# different want params
if e.sendDontHave and e.cid notin b.localStore:
dontHaves.add(e.cid)
# send don't have's to remote
if dontHaves.len > 0:
b.network.request.sendPresence(
peer,
dontHaves.mapIt(
BlockPresence(
cid: it.data.buffer,
`type`: BlockPresenceType.presenceDontHave)))
if not b.scheduleTask(peerCtx):
trace "Unable to schedule task for peer", peer
proc accountHandler*(engine: BlockExcEngine, peer: PeerID, account: Account) {.async.} =
let context = engine.getPeerCtx(peer)
if context.isNil:
return
context.account = account.some
proc paymentHandler*(engine: BlockExcEngine, peer: PeerId, payment: SignedState) {.async.} =
without context =? engine.getPeerCtx(peer).option and
account =? context.account:
return
if channel =? context.paymentChannel:
let sender = account.address
discard engine.wallet.acceptPayment(channel, Asset, sender, payment)
else:
context.paymentChannel = engine.wallet.acceptChannel(payment).option
proc setupPeer*(b: BlockExcEngine, peer: PeerID) =
## Perform initial setup, such as want
## list exchange
##
trace "Setting up new peer", peer
if peer notin b.peers:
b.peers.add(BlockExcPeerCtx(
id: peer
))
# broadcast our want list, the other peer will do the same
if b.wantList.len > 0:
b.network.request.sendWantList(peer, b.wantList, full = true)
if address =? b.pricing.?address:
b.network.request.sendAccount(peer, Account(address: address))
proc dropPeer*(b: BlockExcEngine, peer: PeerID) =
## Cleanup disconnected peer
##
trace "Dropping peer", peer
# drop the peer from the peers table
b.peers.keepItIf( it.id != peer )
proc taskHandler*(b: BlockExcEngine, task: BlockExcPeerCtx) {.gcsafe, async.} =
trace "Handling task for peer", peer = task.id
var wantsBlocks = newAsyncHeapQueue[Entry](queueType = QueueType.Max)
# get blocks and wants to send to the remote
for e in task.peerWants:
if e.wantType == WantType.wantBlock:
await wantsBlocks.push(e)
# TODO: There should be all sorts of accounting of
# bytes sent/received here
if wantsBlocks.len > 0:
let blockFuts = await allFinished(wantsBlocks.mapIt(
b.localStore.getBlock(it.cid)
))
let blocks = blockFuts
.filterIt((not it.failed) and it.read.isOk)
.mapIt(!it.read)
if blocks.len > 0:
b.network.request.sendBlocks(
task.id,
blocks)
# Remove successfully sent blocks
task.peerWants.keepIf(
proc(e: Entry): bool =
not blocks.anyIt( it.cid == e.cid )
)
var wants: seq[BlockPresence]
# do not remove wants from the queue unless
# we send the block or get a cancel
for e in task.peerWants:
if e.wantType == WantType.wantHave:
var presence = Presence(cid: e.cid)
presence.have = b.localStore.hasblock(presence.cid)
if presence.have and price =? b.pricing.?price:
presence.price = price
wants.add(BlockPresence.init(presence))
if wants.len > 0:
b.network.request.sendPresence(task.id, wants)
proc blockexcTaskRunner(b: BlockExcEngine) {.async.} =
## process tasks
##
while b.blockexcRunning:
let peerCtx = await b.taskQueue.pop()
asyncSpawn b.taskHandler(peerCtx)
trace "Exiting blockexc task runner"
proc new*(
T: type BlockExcEngine,
localStore: BlockStore,
wallet: WalletRef,
network: BlockExcNetwork,
concurrentTasks = DefaultConcurrentTasks,
maxRetries = DefaultMaxRetries,
peersPerRequest = DefaultMaxPeersPerRequest): T =
let engine = BlockExcEngine(
localStore: localStore,
pendingBlocks: PendingBlocksManager.new(),
peersPerRequest: peersPerRequest,
network: network,
wallet: wallet,
concurrentTasks: concurrentTasks,
maxRetries: maxRetries,
taskQueue: newAsyncHeapQueue[BlockExcPeerCtx](DefaultTaskQueueSize))
proc peerEventHandler(peerId: PeerID, event: PeerEvent) {.async.} =
if event.kind == PeerEventKind.Joined:
engine.setupPeer(peerId)
else:
engine.dropPeer(peerId)
if not isNil(network.switch):
network.switch.addPeerEventHandler(peerEventHandler, PeerEventKind.Joined)
network.switch.addPeerEventHandler(peerEventHandler, PeerEventKind.Left)
proc blockWantListHandler(
peer: PeerID,
wantList: WantList): Future[void] {.gcsafe.} =
engine.wantListHandler(peer, wantList)
proc blockPresenceHandler(
peer: PeerID,
presence: seq[BlockPresence]): Future[void] {.gcsafe.} =
engine.blockPresenceHandler(peer, presence)
proc blocksHandler(
peer: PeerID,
blocks: seq[bt.Block]): Future[void] {.gcsafe.} =
engine.blocksHandler(peer, blocks)
proc accountHandler(peer: PeerId, account: Account): Future[void] {.gcsafe.} =
engine.accountHandler(peer, account)
proc paymentHandler(peer: PeerId, payment: SignedState): Future[void] {.gcsafe.} =
engine.paymentHandler(peer, payment)
network.handlers = BlockExcHandlers(
onWantList: blockWantListHandler,
onBlocks: blocksHandler,
onPresence: blockPresenceHandler,
onAccount: accountHandler,
onPayment: paymentHandler
)
return engine