nwaku/waku/v2/protocol/waku_swap/waku_swap.nim

307 lines
11 KiB
Nim

## SWAP implements Accounting for Waku. See
## https://github.com/vacp2p/specs/issues/24 for more.
##
## This is based on the SWAP based approach researched by the Swarm team, and
## can be thought of as an economic extension to Bittorrent's tit-for-tat
## economics.
##
## It is quite suitable for accounting for imbalances between peers, and
## specifically for something like the Store protocol.
##
## It is structured as follows:
##
## 1) First a handshake is made, where terms are agreed upon
##
## 2) Then operation occurs as normal with HistoryRequest, HistoryResponse etc
## through store protocol (or otherwise)
##
## 3) When payment threshhold is met, a cheque is sent. This acts as promise to
## pay. Right now it is best thought of as karma points.
##
## Things like settlement is for future work.
##
when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
# TODO Generally clean up errors here, a lot of Exceptions, Defects and KeyErros
#
# On KeyEror specifically:
# Accessing Table's items is prone to KeyError exception when the key does not belong to the table
# such exception can be avoided by calling hasKey() before accessing the key (which is the case in this module)
# but from the compiler point of view, the use of hasKey() does not make any difference in the potential exceptions
# - thus any key access should be wrapped inside try-except
# - or otherwise the exception should be thrown by the proc and handled by the higher level calls
import
std/[tables, options, json],
bearssl/rand,
chronos, chronicles, metrics, stew/results,
libp2p/crypto/crypto,
libp2p/protocols/protocol,
libp2p/protobuf/minprotobuf,
libp2p/stream/connection,
../../node/peer_manager,
./waku_swap_types,
../../../common/protobuf,
../../waku/v2/protocol/waku_swap/waku_swap_contracts
export waku_swap_types
const swapAccountBalanceBuckets = [-Inf, -200.0, -150.0, -100.0, -50.0, 0.0, 50.0, 100.0, 150.0, 200.0, Inf]
declarePublicGauge waku_swap_peers_count, "number of swap peers"
declarePublicGauge waku_swap_errors, "number of swap protocol errors", ["type"]
declarePublicGauge waku_swap_messages, "number of swap messages received", ["type"]
declarePublicHistogram waku_peer_swap_account_balance, "Swap Account Balance for waku peers, aggregated into buckets based on threshold limits", buckets = swapAccountBalanceBuckets
logScope:
topics = "waku swap"
const WakuSwapCodec* = "/vac/waku/swap/2.0.0-beta1"
# Error types (metric label values)
const
dialFailure = "dial_failure"
decodeRpcFailure = "decode_rpc_failure"
# Serialization
# -------------------------------------------------------------------------------
proc encode*(handshake: Handshake): ProtoBuffer =
var output = initProtoBuffer()
output.write3(1, handshake.beneficiary)
output.finish3()
return output
proc encode*(cheque: Cheque): ProtoBuffer =
var output = initProtoBuffer()
output.write3(1, cheque.beneficiary)
output.write3(2, cheque.date)
output.write3(3, cheque.amount)
output.write3(4, cheque.signature)
output.finish3()
return output
proc init*(T: type Handshake, buffer: seq[byte]): ProtoResult[T] =
var beneficiary: seq[byte]
var handshake = Handshake()
let pb = initProtoBuffer(buffer)
discard ? pb.getField(1, handshake.beneficiary)
return ok(handshake)
proc init*(T: type Cheque, buffer: seq[byte]): ProtoResult[T] =
var beneficiary: seq[byte]
var date: uint32
var amount: uint32
var signature: seq[byte]
var cheque = Cheque()
let pb = initProtoBuffer(buffer)
discard ? pb.getField(1, cheque.beneficiary)
discard ? pb.getField(2, cheque.date)
discard ? pb.getField(3, cheque.amount)
discard ? pb.getField(4, cheque.signature)
return ok(cheque)
# Accounting
# -------------------------------------------------------------------------------
#
# We credit and debits peers based on what for now is a form of Karma asset.
# TODO Test for credit/debit operations in succession
# TODO Assume we calculated cheque
proc sendCheque*(ws: WakuSwap, peerId: PeerID) {.async.} =
let connOpt = await ws.peerManager.dialPeer(peerId, WakuSwapCodec)
if connOpt.isNone():
# @TODO more sophisticated error handling here
error "failed to connect to remote peer"
waku_swap_errors.inc(labelValues = [dialFailure])
return
info "sendCheque"
# TODO We get this from the setup of swap setup, dynamic, should be part of setup
# TODO Add beneficiary, etc
var aliceSwapAddress = "0x6C3d502f1a97d4470b881015b83D9Dd1062172e1"
var aliceWalletAddress = "0x6C3d502f1a97d4470b881015b83D9Dd1062172e1"
var signature: string
var res = waku_swap_contracts.signCheque(aliceSwapAddress)
if res.isOk():
info "signCheque ", res=res[]
let json = res[]
signature = json["signature"].getStr()
else:
# To test code paths, this should look different in a production setting
warn "Something went wrong when signing cheque, sending anyway"
info "Signed Cheque", swapAddress = aliceSwapAddress, signature = signature, issuerAddress = aliceWalletAddress
let sigBytes = cast[seq[byte]](signature)
await connOpt.get().writeLP(Cheque(amount: 1, signature: sigBytes, issuerAddress: aliceWalletAddress).encode().buffer)
# Set new balance
ws.accounting[peerId] -= 1
info "New accounting state", accounting = ws.accounting[peerId]
# TODO Authenticate cheque, check beneficiary etc
proc handleCheque*(ws: WakuSwap, cheque: Cheque, peerId: PeerID) {.raises: [Defect, KeyError].} =
info "handle incoming cheque"
# Get the original signer using web3. For now, a static value (0x6C3d502f1a97d4470b881015b83D9Dd1062172e1) will be used.
# Check if web3.eth.personal.ecRecover(messageHash, signature); or an equivalent function has been implemented in nim-web3
let signer = "0x6C3d502f1a97d4470b881015b83D9Dd1062172e1"
# Verify that the Issuer was the signer of the signature
if signer != cheque.issuerAddress:
warn "Invalid cheque: The address of the issuer is different from the signer."
# TODO Redeem cheque here
var signature = cast[string](cheque.signature)
# TODO Where should Alice Swap Address come from? Handshake probably?
# Hacky for now
var aliceSwapAddress = "0x6C3d502f1a97d4470b881015b83D9Dd1062172e1"
info "Redeeming cheque with", swapAddress=aliceSwapAddress, signature=signature
var res = waku_swap_contracts.redeemCheque(aliceSwapAddress, signature)
if res.isOk():
info "redeemCheque ok", redeem=res[]
else:
info "Unable to redeem cheque"
# Check balance here
# TODO How do we get ERC20 address here?
# XXX This one is wrong
# Normally this would be part of initial setup, otherwise we need some temp persistence here
# Possibly as part of handshake?
var erc20address = "0x6C3d502f1a97d4470b881015b83D9Dd1062172e1"
let balRes = waku_swap_contracts.getERC20Balances(erc20address)
if balRes.isOk():
# XXX: Assumes Alice and Bob here...
var bobBalance = balRes[]["bobBalance"].getInt()
info "New balance is", balance = bobBalance
else:
info "Problem getting Bob balance"
# TODO Could imagine scenario where you don't cash cheque but leave it as credit
# In that case, we would probably update accounting state, but keep track of cheques
# When this is true we update accounting state anyway when node is offline,
# makes waku_swap test pass for now
# Consider desired logic here
var stateUpdateOverRide = true
if res.isOk():
info "Updating accounting state with redeemed cheque"
ws.accounting[peerId] += int(cheque.amount)
else:
if stateUpdateOverRide:
info "Updating accounting state with even if cheque failed"
ws.accounting[peerId] += int(cheque.amount)
else:
info "Not updating accounting state with due to bad cheque"
info "New accounting state", accounting = ws.accounting[peerId]
# Log Account Metrics
proc logAccountMetrics*(ws: Wakuswap, peer: PeerId) {.async.}=
waku_peer_swap_account_balance.observe(ws.accounting[peer].int64)
proc init*(wakuSwap: WakuSwap) =
info "wakuSwap init 1"
proc handle(conn: Connection, proto: string) {.async, gcsafe, closure.} =
info "swap handle incoming connection"
var message = await conn.readLp(MaxChequeSize.int)
# XXX This can be handshake, etc
var res = Cheque.init(message)
if res.isErr:
error "failed to decode rpc"
waku_swap_errors.inc(labelValues = [decodeRpcFailure])
return
info "received cheque", value=res.value
waku_swap_messages.inc(labelValues = ["Cheque"])
wakuSwap.handleCheque(res.value, conn.peerId)
proc credit(peerId: PeerID, n: int)
{.gcsafe, closure, raises: [Defect, KeyError, Exception].} =
info "Crediting peer: ", peer=peerId, amount=n
if wakuSwap.accounting.hasKey(peerId):
wakuSwap.accounting[peerId] -= n
else:
wakuSwap.accounting[peerId] = -n
info "Accounting state", accounting = wakuSwap.accounting[peerId]
wakuSwap.applyPolicy(peerId)
# TODO Debit and credit here for Karma asset
proc debit(peerId: PeerID, n: int)
{.gcsafe, closure, raises: [Defect, KeyError, Exception].} =
info "Debiting peer: ", peer=peerId, amount=n
if wakuSwap.accounting.hasKey(peerId):
wakuSwap.accounting[peerId] += n
else:
wakuSwap.accounting[peerId] = n
info "Accounting state", accounting = wakuSwap.accounting[peerId]
wakuSwap.applyPolicy(peerId)
proc applyPolicy(peerId: PeerID)
{.gcsafe, closure, raises: [Defect, KeyError, Exception].} =
# TODO Separate out depending on if policy is soft (accounting only) mock (send cheque but don't cash/verify) hard (actually send funds over testnet)
#Check if the Disconnect Threshold has been hit. Account Balance nears the disconnectThreshold after a Credit has been done
if wakuSwap.accounting[peerId] <= wakuSwap.config.disconnectThreshold:
warn "Disconnect threshhold has been reached: ", threshold=wakuSwap.config.disconnectThreshold, balance=wakuSwap.accounting[peerId]
else:
info "Disconnect threshhold not hit"
#Check if the Payment threshold has been hit. Account Balance nears the paymentThreshold after a Debit has been done
if wakuSwap.accounting[peerId] >= wakuSwap.config.paymentThreshold:
warn "Payment threshhold has been reached: ", threshold=wakuSwap.config.paymentThreshold, balance=wakuSwap.accounting[peerId]
#In soft phase we don't send cheques yet
if wakuSwap.config.mode == Mock:
discard wakuSwap.sendCheque(peerId)
else:
info "Payment threshhold not hit"
waitFor wakuSwap.logAccountMetrics(peerId)
wakuSwap.handler = handle
wakuSwap.codec = WakuSwapCodec
wakuSwap.credit = credit
wakuSwap.debit = debit
wakuswap.applyPolicy = applyPolicy
# TODO Expression return?
proc init*(T: type WakuSwap, peerManager: PeerManager, rng: ref rand.HmacDrbgContext, swapConfig: SwapConfig): T =
info "wakuSwap init 2"
let
accounting = initTable[PeerId, int]()
text = "test"
var ws = WakuSwap(rng: rng,
peerManager: peerManager,
accounting: accounting,
text: text,
config: swapConfig)
ws.init()
return ws
# TODO End to end communication