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

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## 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.
##
import
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std/[tables, options],
bearssl,
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chronos, chronicles, metrics, stew/results,
libp2p/switch,
libp2p/crypto/crypto,
libp2p/protocols/protocol,
libp2p/protobuf/minprotobuf,
libp2p/stream/connection,
../message_notifier,
./waku_swap_types
export waku_swap_types
logScope:
topics = "wakuswap"
const WakuSwapCodec* = "/vac/waku/swap/2.0.0-alpha1"
# Serialization
# -------------------------------------------------------------------------------
proc encode*(handshake: Handshake): ProtoBuffer =
result = initProtoBuffer()
result.write(1, handshake.beneficiary)
proc encode*(cheque: Cheque): ProtoBuffer =
result = initProtoBuffer()
result.write(1, cheque.beneficiary)
result.write(2, cheque.date)
result.write(3, cheque.amount)
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)
ok(handshake)
proc init*(T: type Cheque, buffer: seq[byte]): ProtoResult[T] =
var beneficiary: seq[byte]
var date: uint32
var amount: uint32
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)
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
proc sendCheque*(ws: WakuSwap) {.async.} =
# TODO Better peer selection, for now using hardcoded peer
let peer = ws.peers[0]
let conn = await ws.switch.dial(peer.peerInfo.peerId, peer.peerInfo.addrs, WakuSwapCodec)
info "sendCheque"
# TODO Add beneficiary, etc
# XXX Hardcoded amount for now
await conn.writeLP(Cheque(amount: 1).encode().buffer)
# Set new balance
# XXX Assume peerId is first peer
let peerId = ws.peers[0].peerInfo.peerId
ws.accounting[peerId] -= 1
info "New accounting state", accounting = ws.accounting[peerId]
# TODO Authenticate cheque, check beneficiary etc
proc handleCheque*(ws: WakuSwap, cheque: Cheque) =
info "handle incoming cheque"
# XXX Assume peerId is first peer
let peerId = ws.peers[0].peerInfo.peerId
ws.accounting[peerId] += int(cheque.amount)
info "New accounting state", accounting = ws.accounting[peerId]
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(64*1024)
# XXX This can be handshake, etc
var res = Cheque.init(message)
if res.isErr:
error "failed to decode rpc"
return
info "received cheque", value=res.value
wakuSwap.handleCheque(res.value)
proc credit(peerId: PeerId, n: int) {.gcsafe, closure.} =
info "Crediting peer for", peerId, n
if wakuSwap.accounting.hasKey(peerId):
wakuSwap.accounting[peerId] -= n
else:
wakuSwap.accounting[peerId] = -n
info "Accounting state", accounting = wakuSwap.accounting[peerId]
# TODO Isolate to policy function
# TODO Tunable disconnect threshhold, hard code for PoC
let disconnectThreshhold = 2
if wakuSwap.accounting[peerId] >= disconnectThreshhold:
info "Disconnect threshhold hit, disconnect peer"
else:
info "Disconnect threshhold not hit"
# TODO Debit and credit here for Karma asset
proc debit(peerId: PeerId, n: int) {.gcsafe, closure.} =
info "Debiting peer for", peerId, n
if wakuSwap.accounting.hasKey(peerId):
wakuSwap.accounting[peerId] += n
else:
wakuSwap.accounting[peerId] = n
info "Accounting state", accounting = wakuSwap.accounting[peerId]
# TODO Isolate to policy function
# TODO Tunable payment threshhold, hard code for PoC
let paymentThreshhold = 1
if wakuSwap.accounting[peerId] >= paymentThreshhold:
info "Payment threshhold hit, send cheque"
discard wakuSwap.sendCheque()
else:
info "Payment threshhold not hit"
wakuSwap.handler = handle
wakuSwap.codec = WakuSwapCodec
wakuSwap.credit = credit
wakuSwap.debit = debit
# TODO Expression return?
proc init*(T: type WakuSwap, switch: Switch, rng: ref BrHmacDrbgContext): T =
info "wakuSwap init 2"
new result
result.rng = rng
result.switch = switch
result.accounting = initTable[PeerId, int]()
result.text = "test"
result.init()
proc setPeer*(ws: WakuSwap, peer: PeerInfo) =
ws.peers.add(SwapPeer(peerInfo: peer))
# TODO End to end communication