// Copyright 2017 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
// faucet is a Ether faucet backed by a light client.
package main
//go:generate go-bindata -nometadata -o website.go faucet.html
import (
"bytes"
"context"
"encoding/json"
"flag"
"fmt"
"html/template"
"io/ioutil"
"math"
"math/big"
"net/http"
"net/url"
"os"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/accounts/keystore"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/eth"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/ethclient"
"github.com/ethereum/go-ethereum/ethstats"
"github.com/ethereum/go-ethereum/les"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/discv5"
"github.com/ethereum/go-ethereum/p2p/nat"
"github.com/ethereum/go-ethereum/params"
"golang.org/x/net/websocket"
)
var (
genesisFlag = flag.String("genesis", "", "Genesis json file to seed the chain with")
apiPortFlag = flag.Int("apiport", 8080, "Listener port for the HTTP API connection")
ethPortFlag = flag.Int("ethport", 30303, "Listener port for the devp2p connection")
bootFlag = flag.String("bootnodes", "", "Comma separated bootnode enode URLs to seed with")
netFlag = flag.Uint64("network", 0, "Network ID to use for the Ethereum protocol")
statsFlag = flag.String("ethstats", "", "Ethstats network monitoring auth string")
netnameFlag = flag.String("faucet.name", "", "Network name to assign to the faucet")
payoutFlag = flag.Int("faucet.amount", 1, "Number of Ethers to pay out per user request")
minutesFlag = flag.Int("faucet.minutes", 1440, "Number of minutes to wait between funding rounds")
tiersFlag = flag.Int("faucet.tiers", 3, "Number of funding tiers to enable (x3 time, x2.5 funds)")
accJSONFlag = flag.String("account.json", "", "Key json file to fund user requests with")
accPassFlag = flag.String("account.pass", "", "Decryption password to access faucet funds")
githubUser = flag.String("github.user", "", "GitHub user to authenticate with for Gist access")
githubToken = flag.String("github.token", "", "GitHub personal token to access Gists with")
captchaToken = flag.String("captcha.token", "", "Recaptcha site key to authenticate client side")
captchaSecret = flag.String("captcha.secret", "", "Recaptcha secret key to authenticate server side")
logFlag = flag.Int("loglevel", 3, "Log level to use for Ethereum and the faucet")
)
var (
ether = new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil)
)
func main() {
// Parse the flags and set up the logger to print everything requested
flag.Parse()
log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(*logFlag), log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
// Construct the payout tiers
amounts := make([]string, *tiersFlag)
periods := make([]string, *tiersFlag)
for i := 0; i < *tiersFlag; i++ {
// Calculate the amount for the next tier and format it
amount := float64(*payoutFlag) * math.Pow(2.5, float64(i))
amounts[i] = fmt.Sprintf("%s Ethers", strconv.FormatFloat(amount, 'f', -1, 64))
if amount == 1 {
amounts[i] = strings.TrimSuffix(amounts[i], "s")
}
// Calcualte the period for th enext tier and format it
period := *minutesFlag * int(math.Pow(3, float64(i)))
periods[i] = fmt.Sprintf("%d mins", period)
if period%60 == 0 {
period /= 60
periods[i] = fmt.Sprintf("%d hours", period)
if period%24 == 0 {
period /= 24
periods[i] = fmt.Sprintf("%d days", period)
}
}
if period == 1 {
periods[i] = strings.TrimSuffix(periods[i], "s")
}
}
// Load up and render the faucet website
tmpl, err := Asset("faucet.html")
if err != nil {
log.Crit("Failed to load the faucet template", "err", err)
}
website := new(bytes.Buffer)
err = template.Must(template.New("").Parse(string(tmpl))).Execute(website, map[string]interface{}{
"Network": *netnameFlag,
"Amounts": amounts,
"Periods": periods,
"Recaptcha": *captchaToken,
})
if err != nil {
log.Crit("Failed to render the faucet template", "err", err)
}
// Load and parse the genesis block requested by the user
blob, err := ioutil.ReadFile(*genesisFlag)
if err != nil {
log.Crit("Failed to read genesis block contents", "genesis", *genesisFlag, "err", err)
}
genesis := new(core.Genesis)
if err = json.Unmarshal(blob, genesis); err != nil {
log.Crit("Failed to parse genesis block json", "err", err)
}
// Convert the bootnodes to internal enode representations
var enodes []*discv5.Node
for _, boot := range strings.Split(*bootFlag, ",") {
if url, err := discv5.ParseNode(boot); err == nil {
enodes = append(enodes, url)
} else {
log.Error("Failed to parse bootnode URL", "url", boot, "err", err)
}
}
// Load up the account key and decrypt its password
if blob, err = ioutil.ReadFile(*accPassFlag); err != nil {
log.Crit("Failed to read account password contents", "file", *accPassFlag, "err", err)
}
pass := string(blob)
ks := keystore.NewKeyStore(filepath.Join(os.Getenv("HOME"), ".faucet", "keys"), keystore.StandardScryptN, keystore.StandardScryptP)
if blob, err = ioutil.ReadFile(*accJSONFlag); err != nil {
log.Crit("Failed to read account key contents", "file", *accJSONFlag, "err", err)
}
acc, err := ks.Import(blob, pass, pass)
if err != nil {
log.Crit("Failed to import faucet signer account", "err", err)
}
ks.Unlock(acc, pass)
// Assemble and start the faucet light service
faucet, err := newFaucet(genesis, *ethPortFlag, enodes, *netFlag, *statsFlag, ks, website.Bytes())
if err != nil {
log.Crit("Failed to start faucet", "err", err)
}
defer faucet.close()
if err := faucet.listenAndServe(*apiPortFlag); err != nil {
log.Crit("Failed to launch faucet API", "err", err)
}
}
// request represents an accepted funding request.
type request struct {
Username string `json:"username"` // GitHub user for displaying an avatar
Account common.Address `json:"account"` // Ethereum address being funded
Time time.Time `json:"time"` // Timestamp when te request was accepted
Tx *types.Transaction `json:"tx"` // Transaction funding the account
}
// faucet represents a crypto faucet backed by an Ethereum light client.
type faucet struct {
config *params.ChainConfig // Chain configurations for signing
stack *node.Node // Ethereum protocol stack
client *ethclient.Client // Client connection to the Ethereum chain
index []byte // Index page to serve up on the web
keystore *keystore.KeyStore // Keystore containing the single signer
account accounts.Account // Account funding user faucet requests
nonce uint64 // Current pending nonce of the faucet
price *big.Int // Current gas price to issue funds with
conns []*websocket.Conn // Currently live websocket connections
timeouts map[string]time.Time // History of users and their funding timeouts
reqs []*request // Currently pending funding requests
update chan struct{} // Channel to signal request updates
lock sync.RWMutex // Lock protecting the faucet's internals
}
func newFaucet(genesis *core.Genesis, port int, enodes []*discv5.Node, network uint64, stats string, ks *keystore.KeyStore, index []byte) (*faucet, error) {
// Assemble the raw devp2p protocol stack
stack, err := node.New(&node.Config{
Name: "geth",
Version: params.Version,
DataDir: filepath.Join(os.Getenv("HOME"), ".faucet"),
P2P: p2p.Config{
NAT: nat.Any(),
NoDiscovery: true,
DiscoveryV5: true,
ListenAddr: fmt.Sprintf(":%d", port),
DiscoveryV5Addr: fmt.Sprintf(":%d", port+1),
MaxPeers: 25,
BootstrapNodesV5: enodes,
},
})
if err != nil {
return nil, err
}
// Assemble the Ethereum light client protocol
if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
cfg := eth.DefaultConfig
cfg.SyncMode = downloader.LightSync
cfg.NetworkId = network
cfg.Genesis = genesis
return les.New(ctx, &cfg)
}); err != nil {
return nil, err
}
// Assemble the ethstats monitoring and reporting service'
if stats != "" {
if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
var serv *les.LightEthereum
ctx.Service(&serv)
return ethstats.New(stats, nil, serv)
}); err != nil {
return nil, err
}
}
// Boot up the client and ensure it connects to bootnodes
if err := stack.Start(); err != nil {
return nil, err
}
for _, boot := range enodes {
old, _ := discover.ParseNode(boot.String())
stack.Server().AddPeer(old)
}
// Attach to the client and retrieve and interesting metadatas
api, err := stack.Attach()
if err != nil {
stack.Stop()
return nil, err
}
client := ethclient.NewClient(api)
return &faucet{
config: genesis.Config,
stack: stack,
client: client,
index: index,
keystore: ks,
account: ks.Accounts()[0],
timeouts: make(map[string]time.Time),
update: make(chan struct{}, 1),
}, nil
}
// close terminates the Ethereum connection and tears down the faucet.
func (f *faucet) close() error {
return f.stack.Stop()
}
// listenAndServe registers the HTTP handlers for the faucet and boots it up
// for service user funding requests.
func (f *faucet) listenAndServe(port int) error {
go f.loop()
http.HandleFunc("/", f.webHandler)
http.Handle("/api", websocket.Handler(f.apiHandler))
return http.ListenAndServe(fmt.Sprintf(":%d", port), nil)
}
// webHandler handles all non-api requests, simply flattening and returning the
// faucet website.
func (f *faucet) webHandler(w http.ResponseWriter, r *http.Request) {
w.Write(f.index)
}
// apiHandler handles requests for Ether grants and transaction statuses.
func (f *faucet) apiHandler(conn *websocket.Conn) {
// Start tracking the connection and drop at the end
f.lock.Lock()
f.conns = append(f.conns, conn)
f.lock.Unlock()
defer func() {
f.lock.Lock()
for i, c := range f.conns {
if c == conn {
f.conns = append(f.conns[:i], f.conns[i+1:]...)
break
}
}
f.lock.Unlock()
}()
// Send a few initial stats to the client
balance, _ := f.client.BalanceAt(context.Background(), f.account.Address, nil)
nonce, _ := f.client.NonceAt(context.Background(), f.account.Address, nil)
websocket.JSON.Send(conn, map[string]interface{}{
"funds": balance.Div(balance, ether),
"funded": nonce,
"peers": f.stack.Server().PeerCount(),
"requests": f.reqs,
})
// Send the initial block to the client
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
header, err := f.client.HeaderByNumber(ctx, nil)
cancel()
if err != nil {
log.Error("Failed to retrieve latest header", "err", err)
} else {
websocket.JSON.Send(conn, header)
}
// Keep reading requests from the websocket until the connection breaks
for {
// Fetch the next funding request and validate against github
var msg struct {
URL string `json:"url"`
Tier uint `json:"tier"`
Captcha string `json:"captcha"`
}
if err := websocket.JSON.Receive(conn, &msg); err != nil {
return
}
if !strings.HasPrefix(msg.URL, "https://gist.github.com/") {
websocket.JSON.Send(conn, map[string]string{"error": "URL doesn't link to GitHub Gists"})
continue
}
if msg.Tier >= uint(*tiersFlag) {
websocket.JSON.Send(conn, map[string]string{"error": "Invalid funding tier requested"})
continue
}
log.Info("Faucet funds requested", "gist", msg.URL, "tier", msg.Tier)
// If captcha verifications are enabled, make sure we're not dealing with a robot
if *captchaToken != "" {
form := url.Values{}
form.Add("secret", *captchaSecret)
form.Add("response", msg.Captcha)
res, err := http.PostForm("https://www.google.com/recaptcha/api/siteverify", form)
if err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
continue
}
var result struct {
Success bool `json:"success"`
Errors json.RawMessage `json:"error-codes"`
}
err = json.NewDecoder(res.Body).Decode(&result)
res.Body.Close()
if err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
continue
}
if !result.Success {
log.Warn("Captcha verification failed", "err", string(result.Errors))
websocket.JSON.Send(conn, map[string]string{"error": "Beep-bop, you're a robot!"})
continue
}
}
// Retrieve the gist from the GitHub Gist APIs
parts := strings.Split(msg.URL, "/")
req, _ := http.NewRequest("GET", "https://api.github.com/gists/"+parts[len(parts)-1], nil)
if *githubUser != "" {
req.SetBasicAuth(*githubUser, *githubToken)
}
res, err := http.DefaultClient.Do(req)
if err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
continue
}
var gist struct {
Owner struct {
Login string `json:"login"`
} `json:"owner"`
Files map[string]struct {
Content string `json:"content"`
} `json:"files"`
}
err = json.NewDecoder(res.Body).Decode(&gist)
res.Body.Close()
if err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
continue
}
if gist.Owner.Login == "" {
websocket.JSON.Send(conn, map[string]string{"error": "Anonymous Gists not allowed"})
continue
}
// Iterate over all the files and look for Ethereum addresses
var address common.Address
for _, file := range gist.Files {
if len(file.Content) == 2+common.AddressLength*2 {
address = common.HexToAddress(file.Content)
}
}
if address == (common.Address{}) {
websocket.JSON.Send(conn, map[string]string{"error": "No Ethereum address found to fund"})
continue
}
// Validate the user's existence since the API is unhelpful here
if res, err = http.Head("https://github.com/" + gist.Owner.Login); err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
continue
}
res.Body.Close()
if res.StatusCode != 200 {
websocket.JSON.Send(conn, map[string]string{"error": "Invalid user... boom!"})
continue
}
// Ensure the user didn't request funds too recently
f.lock.Lock()
var (
fund bool
timeout time.Time
)
if timeout = f.timeouts[gist.Owner.Login]; time.Now().After(timeout) {
// User wasn't funded recently, create the funding transaction
amount := new(big.Int).Mul(big.NewInt(int64(*payoutFlag)), ether)
amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil))
amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil))
tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, big.NewInt(21000), f.price, nil)
signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainId)
if err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
f.lock.Unlock()
continue
}
// Submit the transaction and mark as funded if successful
if err := f.client.SendTransaction(context.Background(), signed); err != nil {
websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
f.lock.Unlock()
continue
}
f.reqs = append(f.reqs, &request{
Username: gist.Owner.Login,
Account: address,
Time: time.Now(),
Tx: signed,
})
f.timeouts[gist.Owner.Login] = time.Now().Add(time.Duration(*minutesFlag*int(math.Pow(3, float64(msg.Tier)))) * time.Minute)
fund = true
}
f.lock.Unlock()
// Send an error if too frequent funding, othewise a success
if !fund {
websocket.JSON.Send(conn, map[string]string{"error": fmt.Sprintf("%s left until next allowance", common.PrettyDuration(timeout.Sub(time.Now())))})
continue
}
websocket.JSON.Send(conn, map[string]string{"success": fmt.Sprintf("Funding request accepted for %s into %s", gist.Owner.Login, address.Hex())})
select {
case f.update <- struct{}{}:
default:
}
}
}
// loop keeps waiting for interesting events and pushes them out to connected
// websockets.
func (f *faucet) loop() {
// Wait for chain events and push them to clients
heads := make(chan *types.Header, 16)
sub, err := f.client.SubscribeNewHead(context.Background(), heads)
if err != nil {
log.Crit("Failed to subscribe to head events", "err", err)
}
defer sub.Unsubscribe()
for {
select {
case head := <-heads:
// New chain head arrived, query the current stats and stream to clients
balance, _ := f.client.BalanceAt(context.Background(), f.account.Address, nil)
balance = new(big.Int).Div(balance, ether)
price, _ := f.client.SuggestGasPrice(context.Background())
nonce, _ := f.client.NonceAt(context.Background(), f.account.Address, nil)
f.lock.Lock()
f.price, f.nonce = price, nonce
for len(f.reqs) > 0 && f.reqs[0].Tx.Nonce() < f.nonce {
f.reqs = f.reqs[1:]
}
f.lock.Unlock()
f.lock.RLock()
for _, conn := range f.conns {
if err := websocket.JSON.Send(conn, map[string]interface{}{
"funds": balance,
"funded": f.nonce,
"peers": f.stack.Server().PeerCount(),
"requests": f.reqs,
}); err != nil {
log.Warn("Failed to send stats to client", "err", err)
conn.Close()
continue
}
if err := websocket.JSON.Send(conn, head); err != nil {
log.Warn("Failed to send header to client", "err", err)
conn.Close()
}
}
f.lock.RUnlock()
case <-f.update:
// Pending requests updated, stream to clients
f.lock.RLock()
for _, conn := range f.conns {
if err := websocket.JSON.Send(conn, map[string]interface{}{"requests": f.reqs}); err != nil {
log.Warn("Failed to send requests to client", "err", err)
conn.Close()
}
}
f.lock.RUnlock()
}
}
}
