// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package swap
import (
"context"
"crypto/ecdsa"
"fmt"
"math/big"
"os"
"path/filepath"
"sync"
"time"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/contracts/chequebook"
"github.com/ethereum/go-ethereum/contracts/chequebook/contract"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/swarm/services/swap/swap"
)
// SwAP Swarm Accounting Protocol with
// SWAP^2 Strategies of Withholding Automatic Payments
// SWAP^3 Accreditation: payment via credit SWAP
// using chequebook pkg for delayed payments
// default parameters
var (
autoCashInterval = 300 * time.Second // default interval for autocash
autoCashThreshold = big.NewInt(50000000000000) // threshold that triggers autocash (wei)
autoDepositInterval = 300 * time.Second // default interval for autocash
autoDepositThreshold = big.NewInt(50000000000000) // threshold that triggers autodeposit (wei)
autoDepositBuffer = big.NewInt(100000000000000) // buffer that is surplus for fork protection etc (wei)
buyAt = big.NewInt(20000000000) // maximum chunk price host is willing to pay (wei)
sellAt = big.NewInt(20000000000) // minimum chunk price host requires (wei)
payAt = 100 // threshold that triggers payment {request} (units)
dropAt = 10000 // threshold that triggers disconnect (units)
)
const (
chequebookDeployRetries = 5
chequebookDeployDelay = 1 * time.Second // delay between retries
)
type SwapParams struct {
*swap.Params
*PayProfile
}
type SwapProfile struct {
*swap.Profile
*PayProfile
}
type PayProfile struct {
PublicKey string // check against signature of promise
Contract common.Address // address of chequebook contract
Beneficiary common.Address // recipient address for swarm sales revenue
privateKey *ecdsa.PrivateKey
publicKey *ecdsa.PublicKey
owner common.Address
chbook *chequebook.Chequebook
lock sync.RWMutex
}
func DefaultSwapParams(contract common.Address, prvkey *ecdsa.PrivateKey) *SwapParams {
pubkey := &prvkey.PublicKey
return &SwapParams{
PayProfile: &PayProfile{
PublicKey: common.ToHex(crypto.FromECDSAPub(pubkey)),
Contract: contract,
Beneficiary: crypto.PubkeyToAddress(*pubkey),
privateKey: prvkey,
publicKey: pubkey,
owner: crypto.PubkeyToAddress(*pubkey),
},
Params: &swap.Params{
Profile: &swap.Profile{
BuyAt: buyAt,
SellAt: sellAt,
PayAt: uint(payAt),
DropAt: uint(dropAt),
},
Strategy: &swap.Strategy{
AutoCashInterval: autoCashInterval,
AutoCashThreshold: autoCashThreshold,
AutoDepositInterval: autoDepositInterval,
AutoDepositThreshold: autoDepositThreshold,
AutoDepositBuffer: autoDepositBuffer,
},
},
}
}
// swap constructor, parameters
// * global chequebook, assume deployed service and
// * the balance is at buffer.
// swap.Add(n) called in netstore
// n > 0 called when sending chunks = receiving retrieve requests
// OR sending cheques.
// n < 0 called when receiving chunks = receiving delivery responses
// OR receiving cheques.
func NewSwap(local *SwapParams, remote *SwapProfile, backend chequebook.Backend, proto swap.Protocol) (self *swap.Swap, err error) {
var (
ctx = context.TODO()
ok bool
in *chequebook.Inbox
out *chequebook.Outbox
)
// check if remote chequebook is valid
// insolvent chequebooks suicide so will signal as invalid
// TODO: monitoring a chequebooks events
ok, err = chequebook.ValidateCode(ctx, backend, remote.Contract)
if !ok {
log.Info(fmt.Sprintf("invalid contract %v for peer %v: %v)", remote.Contract.Hex()[:8], proto, err))
} else {
// remote contract valid, create inbox
in, err = chequebook.NewInbox(local.privateKey, remote.Contract, local.Beneficiary, crypto.ToECDSAPub(common.FromHex(remote.PublicKey)), backend)
if err != nil {
log.Warn(fmt.Sprintf("unable to set up inbox for chequebook contract %v for peer %v: %v)", remote.Contract.Hex()[:8], proto, err))
}
}
// check if local chequebook contract is valid
ok, err = chequebook.ValidateCode(ctx, backend, local.Contract)
if !ok {
log.Warn(fmt.Sprintf("unable to set up outbox for peer %v: chequebook contract (owner: %v): %v)", proto, local.owner.Hex(), err))
} else {
out = chequebook.NewOutbox(local.Chequebook(), remote.Beneficiary)
}
pm := swap.Payment{
In: in,
Out: out,
Buys: out != nil,
Sells: in != nil,
}
self, err = swap.New(local.Params, pm, proto)
if err != nil {
return
}
// remote profile given (first) in handshake
self.SetRemote(remote.Profile)
var buy, sell string
if self.Buys {
buy = "purchase from peer enabled at " + remote.SellAt.String() + " wei/chunk"
} else {
buy = "purchase from peer disabled"
}
if self.Sells {
sell = "selling to peer enabled at " + local.SellAt.String() + " wei/chunk"
} else {
sell = "selling to peer disabled"
}
log.Warn(fmt.Sprintf("SWAP arrangement with <%v>: %v; %v)", proto, buy, sell))
return
}
func (self *SwapParams) Chequebook() *chequebook.Chequebook {
defer self.lock.Unlock()
self.lock.Lock()
return self.chbook
}
func (self *SwapParams) PrivateKey() *ecdsa.PrivateKey {
return self.privateKey
}
// func (self *SwapParams) PublicKey() *ecdsa.PublicKey {
// return self.publicKey
// }
func (self *SwapParams) SetKey(prvkey *ecdsa.PrivateKey) {
self.privateKey = prvkey
self.publicKey = &prvkey.PublicKey
}
// setChequebook(path, backend) wraps the
// chequebook initialiser and sets up autoDeposit to cover spending.
func (self *SwapParams) SetChequebook(ctx context.Context, backend chequebook.Backend, path string) error {
self.lock.Lock()
contract := self.Contract
self.lock.Unlock()
valid, err := chequebook.ValidateCode(ctx, backend, contract)
if err != nil {
return err
} else if valid {
return self.newChequebookFromContract(path, backend)
}
return self.deployChequebook(ctx, backend, path)
}
func (self *SwapParams) deployChequebook(ctx context.Context, backend chequebook.Backend, path string) error {
opts := bind.NewKeyedTransactor(self.privateKey)
opts.Value = self.AutoDepositBuffer
opts.Context = ctx
log.Info(fmt.Sprintf("Deploying new chequebook (owner: %v)", opts.From.Hex()))
contract, err := deployChequebookLoop(opts, backend)
if err != nil {
log.Error(fmt.Sprintf("unable to deploy new chequebook: %v", err))
return err
}
log.Info(fmt.Sprintf("new chequebook deployed at %v (owner: %v)", contract.Hex(), opts.From.Hex()))
// need to save config at this point
self.lock.Lock()
self.Contract = contract
err = self.newChequebookFromContract(path, backend)
self.lock.Unlock()
if err != nil {
log.Warn(fmt.Sprintf("error initialising cheque book (owner: %v): %v", opts.From.Hex(), err))
}
return err
}
// repeatedly tries to deploy a chequebook.
func deployChequebookLoop(opts *bind.TransactOpts, backend chequebook.Backend) (addr common.Address, err error) {
var tx *types.Transaction
for try := 0; try < chequebookDeployRetries; try++ {
if try > 0 {
time.Sleep(chequebookDeployDelay)
}
if _, tx, _, err = contract.DeployChequebook(opts, backend); err != nil {
log.Warn(fmt.Sprintf("can't send chequebook deploy tx (try %d): %v", try, err))
continue
}
if addr, err = bind.WaitDeployed(opts.Context, backend, tx); err != nil {
log.Warn(fmt.Sprintf("chequebook deploy error (try %d): %v", try, err))
continue
}
return addr, nil
}
return addr, err
}
// initialise the chequebook from a persisted json file or create a new one
// caller holds the lock
func (self *SwapParams) newChequebookFromContract(path string, backend chequebook.Backend) error {
hexkey := common.Bytes2Hex(self.Contract.Bytes())
err := os.MkdirAll(filepath.Join(path, "chequebooks"), os.ModePerm)
if err != nil {
return fmt.Errorf("unable to create directory for chequebooks: %v", err)
}
chbookpath := filepath.Join(path, "chequebooks", hexkey+".json")
self.chbook, err = chequebook.LoadChequebook(chbookpath, self.privateKey, backend, true)
if err != nil {
self.chbook, err = chequebook.NewChequebook(chbookpath, self.Contract, self.privateKey, backend)
if err != nil {
log.Warn(fmt.Sprintf("unable to initialise chequebook (owner: %v): %v", self.owner.Hex(), err))
return fmt.Errorf("unable to initialise chequebook (owner: %v): %v", self.owner.Hex(), err)
}
}
self.chbook.AutoDeposit(self.AutoDepositInterval, self.AutoDepositThreshold, self.AutoDepositBuffer)
log.Info(fmt.Sprintf("auto deposit ON for %v -> %v: interval = %v, threshold = %v, buffer = %v)", crypto.PubkeyToAddress(*(self.publicKey)).Hex()[:8], self.Contract.Hex()[:8], self.AutoDepositInterval, self.AutoDepositThreshold, self.AutoDepositBuffer))
return nil
}
