nim-dagger/codex/blockexchange/engine/engine.nim

491 lines
14 KiB
Nim

## Nim-Codex
## 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 std/sets
import std/options
import std/algorithm
import pkg/chronos
import pkg/chronicles
import pkg/libp2p
import ../../stores/blockstore
import ../../blocktype as bt
import ../../utils
import ../protobuf/blockexc
import ../protobuf/presence
import ../network
import ../peers
import ./payments
import ./discovery
import ./pendingblocks
export peers, pendingblocks, payments, discovery
logScope:
topics = "codex blockexc engine"
const
DefaultMaxPeersPerRequest* = 10
DefaultTaskQueueSize = 100
DefaultConcurrentTasks = 10
DefaultMaxRetries = 3
DefaultConcurrentDiscRequests = 10
DefaultConcurrentAdvertRequests = 10
DefaultDiscoveryTimeout = 1.minutes
DefaultMaxQueriedBlocksCache = 1000
DefaultMinPeersPerBlock = 3
type
TaskHandler* = proc(task: BlockExcPeerCtx): Future[void] {.gcsafe.}
TaskScheduler* = proc(task: BlockExcPeerCtx): bool {.gcsafe.}
BlockExcEngine* = ref object of RootObj
localStore*: BlockStore # Local block store for this instance
network*: BlockExcNetwork # Petwork interface
peers*: PeerCtxStore # Peers we're currently actively exchanging with
taskQueue*: AsyncHeapQueue[BlockExcPeerCtx] # Peers we're currently processing tasks for
concurrentTasks: int # Number of concurrent peers we're serving at any given time
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
discovery*: DiscoveryEngine
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 )
# 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
##
await b.discovery.start()
trace "Blockexc starting with concurrent tasks", tasks = b.concurrentTasks
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
##
await b.discovery.stop()
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] {.async.} =
## Request a block from remotes
##
trace "Requesting block", cid = $cid
if cid in b.pendingBlocks:
return await b.pendingBlocks.getWantHandle(cid, timeout)
let
blk = b.pendingBlocks.getWantHandle(cid, timeout)
var
peers = b.peers.selectCheapest(cid)
if peers.len <= 0:
peers = toSeq(b.peers) # Get any peer
if peers.len <= 0:
trace "No peers to request blocks from", cid = $cid
b.discovery.queueFindBlocksReq(@[cid])
return await blk
let
blockPeer = peers[0] # get cheapest
# request block
await b.network.request.sendWantList(
blockPeer.id,
@[cid],
wantType = WantType.wantBlock) # we want this remote to send us a block
if (peers.len - 1) == 0:
trace "Not enough peers to send want list to", cid = $cid
b.discovery.queueFindBlocksReq(@[cid])
return await 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[1..stop]:
if cid notin p.peerHave:
# just send wants
await b.network.request.sendWantList(
p.id,
@[cid],
wantType = WantType.wantHave) # we only want to know if the peer has the block
return await blk
proc blockPresenceHandler*(
b: BlockExcEngine,
peer: PeerID,
blocks: seq[BlockPresence]) {.async.} =
## Handle block presence
##
trace "Received presence update for peer", peer
let peerCtx = b.peers.get(peer)
if isNil(peerCtx):
return
for blk in blocks:
if presence =? Presence.init(blk):
peerCtx.updatePresence(presence)
var
cids = toSeq(b.pendingBlocks.wantList).filterIt(
it in peerCtx.peerHave
)
trace "Received presence update for cids", peer, count = cids.len
if cids.len > 0:
await b.network.request.sendWantList(
peer,
cids,
wantType = WantType.wantBlock) # we want this remote to send us a block
# if none of the connected peers report our wants in their have list,
# fire up discovery
b.discovery.queueFindBlocksReq(
toSeq(b.pendingBlocks.wantList)
.filter do(cid: Cid) -> bool:
not b.peers.anyIt( cid in it.peerHave ))
proc scheduleTasks(b: BlockExcEngine, blocks: seq[bt.Block]) {.async.} =
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:
if await (c in b.localStore):
if b.scheduleTask(p):
trace "Task scheduled for peer", peer = p.id
else:
trace "Unable to schedule task for peer", peer = p.id
break # do next peer
proc resolveBlocks*(b: BlockExcEngine, blocks: seq[bt.Block]) {.async.} =
## Resolve pending blocks from the pending blocks manager
## and schedule any new task to be ran
##
trace "Resolving blocks", blocks = blocks.len
b.pendingBlocks.resolve(blocks)
await b.scheduleTasks(blocks)
b.discovery.queueProvideBlocksReq(blocks.mapIt( it.cid ))
proc payForBlocks(engine: BlockExcEngine,
peer: BlockExcPeerCtx,
blocks: seq[bt.Block]) {.async.} =
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)):
await 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 isErr (await b.localStore.putBlock(blk)):
trace "Unable to store block", cid = blk.cid
await b.resolveBlocks(blocks)
let peerCtx = b.peers.get(peer)
if peerCtx != nil:
await 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.peers.get(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:
if not(await e.cid in b.localStore):
dontHaves.add(e.cid)
# send don't have's to remote
if dontHaves.len > 0:
await 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.peers.get(peer)
if context.isNil:
return
context.account = account.some
proc paymentHandler*(
engine: BlockExcEngine,
peer: PeerId,
payment: SignedState) {.async.} =
without context =? engine.peers.get(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) {.async.} =
## 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.pendingBlocks.len > 0:
await b.network.request.sendWantList(
peer, toSeq(b.pendingBlocks.wantList), full = true)
if address =? b.pricing.?address:
await 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.remove(peer)
proc taskHandler*(b: BlockExcEngine, task: BlockExcPeerCtx) {.gcsafe, async.} =
trace "Handling task for peer", peer = task.id
# PART 1: Send to the peer blocks he wants to get,
# if they present in our local store
# TODO: There should be all sorts of accounting of
# bytes sent/received here
var wantsBlocks = task.peerWants.filterIt(it.wantType == WantType.wantBlock)
if wantsBlocks.len > 0:
wantsBlocks.sort(SortOrder.Descending)
let blockFuts = await allFinished(wantsBlocks.mapIt(
b.localStore.getBlock(it.cid)
))
# Extract succesfully received blocks
let blocks = blockFuts
.filterIt(it.completed and it.read.isOk and it.read.get.isSome)
.mapIt(it.read.get.get)
if blocks.len > 0:
trace "Sending blocks to peer", peer = task.id, blocks = blocks.len
await 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 )
)
# PART 2: Send to the peer prices of the blocks he wants to discover,
# if they present in our local store
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 = await (presence.cid in b.localStore)
if presence.have and price =? b.pricing.?price:
presence.price = price
wants.add(BlockPresence.init(presence))
if wants.len > 0:
await b.network.request.sendPresence(task.id, wants)
proc blockexcTaskRunner(b: BlockExcEngine) {.async.} =
## process tasks
##
trace "Starting blockexc task runner"
while b.blockexcRunning:
let
peerCtx = await b.taskQueue.pop()
trace "Got new task from queue", peerId = peerCtx.id
await b.taskHandler(peerCtx)
trace "Exiting blockexc task runner"
proc new*(
T: type BlockExcEngine,
localStore: BlockStore,
wallet: WalletRef,
network: BlockExcNetwork,
discovery: DiscoveryEngine,
peerStore: PeerCtxStore,
pendingBlocks: PendingBlocksManager,
concurrentTasks = DefaultConcurrentTasks,
peersPerRequest = DefaultMaxPeersPerRequest): T =
let
engine = BlockExcEngine(
localStore: localStore,
peers: peerStore,
pendingBlocks: pendingBlocks,
peersPerRequest: peersPerRequest,
network: network,
wallet: wallet,
concurrentTasks: concurrentTasks,
taskQueue: newAsyncHeapQueue[BlockExcPeerCtx](DefaultTaskQueueSize),
discovery: discovery)
proc peerEventHandler(peerId: PeerID, event: PeerEvent) {.async.} =
if event.kind == PeerEventKind.Joined:
await 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