ethstats.go

// 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 ethstats implements the network stats reporting service.
package ethstats

import (
	"encoding/json"
	"errors"
	"fmt"
	"math/big"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"time"

	"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/event"
	"github.com/ethereum/go-ethereum/les"
	"github.com/ethereum/go-ethereum/logger"
	"github.com/ethereum/go-ethereum/logger/glog"
	"github.com/ethereum/go-ethereum/node"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/rpc"
	"golang.org/x/net/websocket"
)

// historyUpdateRange is the number of blocks a node should report upon login or
// history request.
const historyUpdateRange = 50

// Service implements an Ethereum netstats reporting daemon that pushes local
// chain statistics up to a monitoring server.
type Service struct {
	stack *node.Node // Temporary workaround, remove when API finalized

	server *p2p.Server        // Peer-to-peer server to retrieve networking infos
	eth    *eth.Ethereum      // Full Ethereum service if monitoring a full node
	les    *les.LightEthereum // Light Ethereum service if monitoring a light node

	node string // Name of the node to display on the monitoring page
	pass string // Password to authorize access to the monitoring page
	host string // Remote address of the monitoring service

	pongCh chan struct{} // Pong notifications are fed into this channel
	histCh chan []uint64 // History request block numbers are fed into this channel
}

// New returns a monitoring service ready for stats reporting.
func New(url string, ethServ *eth.Ethereum, lesServ *les.LightEthereum) (*Service, error) {
	// Parse the netstats connection url
	re := regexp.MustCompile("([^:@]*)(:([^@]*))?@(.+)")
	parts := re.FindStringSubmatch(url)
	if len(parts) != 5 {
		return nil, fmt.Errorf("invalid netstats url: \"%s\", should be nodename:secret@host:port", url)
	}
	// Assemble and return the stats service
	return &Service{
		eth:    ethServ,
		les:    lesServ,
		node:   parts[1],
		pass:   parts[3],
		host:   parts[4],
		pongCh: make(chan struct{}),
		histCh: make(chan []uint64, 1),
	}, nil
}

// Protocols implements node.Service, returning the P2P network protocols used
// by the stats service (nil as it doesn't use the devp2p overlay network).
func (s *Service) Protocols() []p2p.Protocol { return nil }

// APIs implements node.Service, returning the RPC API endpoints provided by the
// stats service (nil as it doesn't provide any user callable APIs).
func (s *Service) APIs() []rpc.API { return nil }

// Start implements node.Service, starting up the monitoring and reporting daemon.
func (s *Service) Start(server *p2p.Server) error {
	s.server = server
	go s.loop()

	glog.V(logger.Info).Infoln("Stats daemon started")
	return nil
}

// Stop implements node.Service, terminating the monitoring and reporting daemon.
func (s *Service) Stop() error {
	glog.V(logger.Info).Infoln("Stats daemon stopped")
	return nil
}

// loop keeps trying to connect to the netstats server, reporting chain events
// until termination.
func (s *Service) loop() {
	// Subscribe tso chain events to execute updates on
	var emux *event.TypeMux
	if s.eth != nil {
		emux = s.eth.EventMux()
	} else {
		emux = s.les.EventMux()
	}
	headSub := emux.Subscribe(core.ChainHeadEvent{})
	defer headSub.Unsubscribe()

	txSub := emux.Subscribe(core.TxPreEvent{})
	defer txSub.Unsubscribe()

	// Loop reporting until termination
	for {
		// Establish a websocket connection to the server and authenticate the node
		url := fmt.Sprintf("%s/api", s.host)
		if !strings.Contains(url, "://") {
			url = "wss://" + url
		}
		conn, err := websocket.Dial(url, "", "http://localhost/")
		if err != nil {
			glog.V(logger.Warn).Infof("Stats server unreachable: %v", err)
			time.Sleep(10 * time.Second)
			continue
		}
		in := json.NewDecoder(conn)
		out := json.NewEncoder(conn)

		if err = s.login(in, out); err != nil {
			glog.V(logger.Warn).Infof("Stats login failed: %v", err)
			conn.Close()
			time.Sleep(10 * time.Second)
			continue
		}
		go s.readLoop(conn, in)

		// Send the initial stats so our node looks decent from the get go
		if err = s.report(out); err != nil {
			glog.V(logger.Warn).Infof("Initial stats report failed: %v", err)
			conn.Close()
			continue
		}
		if err = s.reportHistory(out, nil); err != nil {
			glog.V(logger.Warn).Infof("History report failed: %v", err)
			conn.Close()
			continue
		}
		// Keep sending status updates until the connection breaks
		fullReport := time.NewTicker(15 * time.Second)

		for err == nil {
			select {
			case <-fullReport.C:
				if err = s.report(out); err != nil {
					glog.V(logger.Warn).Infof("Full stats report failed: %v", err)
				}
			case list := <-s.histCh:
				if err = s.reportHistory(out, list); err != nil {
					glog.V(logger.Warn).Infof("Block history report failed: %v", err)
				}
			case head, ok := <-headSub.Chan():
				if !ok { // node stopped
					conn.Close()
					return
				}
				if err = s.reportBlock(out, head.Data.(core.ChainHeadEvent).Block); err != nil {
					glog.V(logger.Warn).Infof("Block stats report failed: %v", err)
				}
				if err = s.reportPending(out); err != nil {
					glog.V(logger.Warn).Infof("Post-block transaction stats report failed: %v", err)
				}
			case _, ok := <-txSub.Chan():
				if !ok { // node stopped
					conn.Close()
					return
				}
				// Exhaust events to avoid reporting too frequently
				for exhausted := false; !exhausted; {
					select {
					case <-headSub.Chan():
					default:
						exhausted = true
					}
				}
				if err = s.reportPending(out); err != nil {
					glog.V(logger.Warn).Infof("Transaction stats report failed: %v", err)
				}
			}
		}
		// Make sure the connection is closed
		conn.Close()
	}
}

// readLoop loops as long as the connection is alive and retrieves data packets
// from the network socket. If any of them match an active request, it forwards
// it, if they themselves are requests it initiates a reply, and lastly it drops
// unknown packets.
func (s *Service) readLoop(conn *websocket.Conn, in *json.Decoder) {
	// If the read loop exists, close the connection
	defer conn.Close()

	for {
		// Retrieve the next generic network packet and bail out on error
		var msg map[string][]interface{}
		if err := in.Decode(&msg); err != nil {
			glog.V(logger.Warn).Infof("Failed to decode stats server message: %v", err)
			return
		}
		if len(msg["emit"]) == 0 {
			glog.V(logger.Warn).Infof("Stats server sent non-broadcast: %v", msg)
			return
		}
		command, ok := msg["emit"][0].(string)
		if !ok {
			glog.V(logger.Warn).Infof("Invalid stats server message type: %v", msg["emit"][0])
			return
		}
		// If the message is a ping reply, deliver (someone must be listening!)
		if len(msg["emit"]) == 2 && command == "node-pong" {
			select {
			case s.pongCh <- struct{}{}:
				// Pong delivered, continue listening
				continue
			default:
				// Ping routine dead, abort
				glog.V(logger.Warn).Infof("Stats server pinger seems to have died")
				return
			}
		}
		// If the message is a history request, forward to the event processor
		if len(msg["emit"]) == 2 && command == "history" {
			// Make sure the request is valid and doesn't crash us
			request, ok := msg["emit"][1].(map[string]interface{})
			if !ok {
				glog.V(logger.Warn).Infof("Invalid history request: %v", msg["emit"][1])
				return
			}
			list, ok := request["list"].([]interface{})
			if !ok {
				glog.V(logger.Warn).Infof("Invalid history block list: %v", request["list"])
				return
			}
			// Convert the block number list to an integer list
			numbers := make([]uint64, len(list))
			for i, num := range list {
				n, ok := num.(float64)
				if !ok {
					glog.V(logger.Warn).Infof("Invalid history block number: %v", num)
					return
				}
				numbers[i] = uint64(n)
			}
			select {
			case s.histCh <- numbers:
				continue
			default:
			}
		}
		// Report anything else and continue
		glog.V(logger.Info).Infof("Unknown stats message: %v", msg)
	}
}

// nodeInfo is the collection of metainformation about a node that is displayed
// on the monitoring page.
type nodeInfo struct {
	Name     string `json:"name"`
	Node     string `json:"node"`
	Port     int    `json:"port"`
	Network  string `json:"net"`
	Protocol string `json:"protocol"`
	API      string `json:"api"`
	Os       string `json:"os"`
	OsVer    string `json:"os_v"`
	Client   string `json:"client"`
	History  bool   `json:"canUpdateHistory"`
}

// authMsg is the authentication infos needed to login to a monitoring server.
type authMsg struct {
	Id     string   `json:"id"`
	Info   nodeInfo `json:"info"`
	Secret string   `json:"secret"`
}

// login tries to authorize the client at the remote server.
func (s *Service) login(in *json.Decoder, out *json.Encoder) error {
	// Construct and send the login authentication
	infos := s.server.NodeInfo()

	var network, protocol string
	if info := infos.Protocols["eth"]; info != nil {
		network = strconv.Itoa(info.(*eth.EthNodeInfo).Network)
		protocol = fmt.Sprintf("eth/%d", eth.ProtocolVersions[0])
	} else {
		network = strconv.Itoa(infos.Protocols["les"].(*eth.EthNodeInfo).Network)
		protocol = fmt.Sprintf("les/%d", les.ProtocolVersions[0])
	}
	auth := &authMsg{
		Id: s.node,
		Info: nodeInfo{
			Name:     s.node,
			Node:     infos.Name,
			Port:     infos.Ports.Listener,
			Network:  network,
			Protocol: protocol,
			API:      "No",
			Os:       runtime.GOOS,
			OsVer:    runtime.GOARCH,
			Client:   "0.1.1",
			History:  true,
		},
		Secret: s.pass,
	}
	login := map[string][]interface{}{
		"emit": {"hello", auth},
	}
	if err := out.Encode(login); err != nil {
		return err
	}
	// Retrieve the remote ack or connection termination
	var ack map[string][]string
	if err := in.Decode(&ack); err != nil || len(ack["emit"]) != 1 || ack["emit"][0] != "ready" {
		return errors.New("unauthorized")
	}
	return nil
}

// report collects all possible data to report and send it to the stats server.
// This should only be used on reconnects or rarely to avoid overloading the
// server. Use the individual methods for reporting subscribed events.
func (s *Service) report(out *json.Encoder) error {
	if err := s.reportLatency(out); err != nil {
		return err
	}
	if err := s.reportBlock(out, nil); err != nil {
		return err
	}
	if err := s.reportPending(out); err != nil {
		return err
	}
	if err := s.reportStats(out); err != nil {
		return err
	}
	return nil
}

// reportLatency sends a ping request to the server, measures the RTT time and
// finally sends a latency update.
func (s *Service) reportLatency(out *json.Encoder) error {
	// Send the current time to the ethstats server
	start := time.Now()

	ping := map[string][]interface{}{
		"emit": {"node-ping", map[string]string{
			"id":         s.node,
			"clientTime": start.String(),
		}},
	}
	if err := out.Encode(ping); err != nil {
		return err
	}
	// Wait for the pong request to arrive back
	select {
	case <-s.pongCh:
		// Pong delivered, report the latency
	case <-time.After(3 * time.Second):
		// Ping timeout, abort
		return errors.New("ping timed out")
	}
	// Send back the measured latency
	latency := map[string][]interface{}{
		"emit": {"latency", map[string]string{
			"id":      s.node,
			"latency": strconv.Itoa(int((time.Since(start) / time.Duration(2)).Nanoseconds() / 1000000)),
		}},
	}
	return out.Encode(latency)
}

// blockStats is the information to report about individual blocks.
type blockStats struct {
	Number    *big.Int       `json:"number"`
	Hash      common.Hash    `json:"hash"`
	Timestamp *big.Int       `json:"timestamp"`
	Miner     common.Address `json:"miner"`
	GasUsed   *big.Int       `json:"gasUsed"`
	GasLimit  *big.Int       `json:"gasLimit"`
	Diff      string         `json:"difficulty"`
	TotalDiff string         `json:"totalDifficulty"`
	Txs       txStats        `json:"transactions"`
	Uncles    uncleStats     `json:"uncles"`
}

// txStats is a custom wrapper around a transaction array to force serializing
// empty arrays instead of returning null for them.
type txStats []*types.Transaction

func (s txStats) MarshalJSON() ([]byte, error) {
	if txs := ([]*types.Transaction)(s); len(txs) > 0 {
		return json.Marshal(txs)
	}
	return []byte("[]"), nil
}

// uncleStats is a custom wrapper around an uncle array to force serializing
// empty arrays instead of returning null for them.
type uncleStats []*types.Header

func (s uncleStats) MarshalJSON() ([]byte, error) {
	if uncles := ([]*types.Header)(s); len(uncles) > 0 {
		return json.Marshal(uncles)
	}
	return []byte("[]"), nil
}

// reportBlock retrieves the current chain head and repors it to the stats server.
func (s *Service) reportBlock(out *json.Encoder, block *types.Block) error {
	// Assemble the block stats report and send it to the server
	stats := map[string]interface{}{
		"id":    s.node,
		"block": s.assembleBlockStats(block),
	}
	report := map[string][]interface{}{
		"emit": {"block", stats},
	}
	return out.Encode(report)
}

// assembleBlockStats retrieves any required metadata to report a single block
// and assembles the block stats. If block is nil, the current head is processed.
func (s *Service) assembleBlockStats(block *types.Block) *blockStats {
	// Gather the block infos from the local blockchain
	var (
		header *types.Header
		td     *big.Int
		txs    []*types.Transaction
		uncles []*types.Header
	)
	if s.eth != nil {
		// Full nodes have all needed information available
		if block == nil {
			block = s.eth.BlockChain().CurrentBlock()
		}
		header = block.Header()
		td = s.eth.BlockChain().GetTd(header.Hash(), header.Number.Uint64())

		txs = block.Transactions()
		uncles = block.Uncles()
	} else {
		// Light nodes would need on-demand lookups for transactions/uncles, skip
		if block != nil {
			header = block.Header()
		} else {
			header = s.les.BlockChain().CurrentHeader()
		}
		td = s.les.BlockChain().GetTd(header.Hash(), header.Number.Uint64())
	}
	// Assemble and return the block stats
	return &blockStats{
		Number:    header.Number,
		Hash:      header.Hash(),
		Timestamp: header.Time,
		Miner:     header.Coinbase,
		GasUsed:   new(big.Int).Set(header.GasUsed),
		GasLimit:  new(big.Int).Set(header.GasLimit),
		Diff:      header.Difficulty.String(),
		TotalDiff: td.String(),
		Txs:       txs,
		Uncles:    uncles,
	}
}

// reportHistory retrieves the most recent batch of blocks and reports it to the
// stats server.
func (s *Service) reportHistory(out *json.Encoder, list []uint64) error {
	// Figure out the indexes that need reporting
	indexes := make([]uint64, 0, historyUpdateRange)
	if len(list) > 0 {
		// Specific indexes requested, send them back in particular
		indexes = append(indexes, list...)
	} else {
		// No indexes requested, send back the top ones
		var head *types.Header
		if s.eth != nil {
			head = s.eth.BlockChain().CurrentHeader()
		} else {
			head = s.les.BlockChain().CurrentHeader()
		}
		start := head.Number.Int64() - historyUpdateRange
		if start < 0 {
			start = 0
		}
		for i := uint64(start); i <= head.Number.Uint64(); i++ {
			indexes = append(indexes, i)
		}
	}
	// Gather the batch of blocks to report
	history := make([]*blockStats, len(indexes))
	for i, number := range indexes {
		if s.eth != nil {
			history[i] = s.assembleBlockStats(s.eth.BlockChain().GetBlockByNumber(number))
		} else {
			history[i] = s.assembleBlockStats(types.NewBlockWithHeader(s.les.BlockChain().GetHeaderByNumber(number)))
		}
	}
	// Assemble the history report and send it to the server
	stats := map[string]interface{}{
		"id":      s.node,
		"history": history,
	}
	report := map[string][]interface{}{
		"emit": {"history", stats},
	}
	return out.Encode(report)
}

// pendStats is the information to report about pending transactions.
type pendStats struct {
	Pending int `json:"pending"`
}

// reportPending retrieves the current number of pending transactions and reports
// it to the stats server.
func (s *Service) reportPending(out *json.Encoder) error {
	// Retrieve the pending count from the local blockchain
	var pending int
	if s.eth != nil {
		pending, _ = s.eth.TxPool().Stats()
	} else {
		pending = s.les.TxPool().Stats()
	}
	// Assemble the transaction stats and send it to the server
	stats := map[string]interface{}{
		"id": s.node,
		"stats": &pendStats{
			Pending: pending,
		},
	}
	report := map[string][]interface{}{
		"emit": {"pending", stats},
	}
	return out.Encode(report)
}

// blockStats is the information to report about the local node.
type nodeStats struct {
	Active   bool `json:"active"`
	Syncing  bool `json:"syncing"`
	Mining   bool `json:"mining"`
	Hashrate int  `json:"hashrate"`
	Peers    int  `json:"peers"`
	GasPrice int  `json:"gasPrice"`
	Uptime   int  `json:"uptime"`
}

// reportPending retrieves various stats about the node at the networking and
// mining layer and reports it to the stats server.
func (s *Service) reportStats(out *json.Encoder) error {
	// Gather the syncing and mining infos from the local miner instance
	var (
		mining   bool
		hashrate int
		syncing  bool
		gasprice int
	)
	if s.eth != nil {
		mining = s.eth.Miner().Mining()
		hashrate = int(s.eth.Miner().HashRate())

		sync := s.eth.Downloader().Progress()
		syncing = s.eth.BlockChain().CurrentHeader().Number.Uint64() >= sync.HighestBlock

		gasprice = int(s.eth.Miner().GasPrice().Uint64())
	} else {
		sync := s.les.Downloader().Progress()
		syncing = s.les.BlockChain().CurrentHeader().Number.Uint64() >= sync.HighestBlock
	}
	stats := map[string]interface{}{
		"id": s.node,
		"stats": &nodeStats{
			Active:   true,
			Mining:   mining,
			Hashrate: hashrate,
			Peers:    s.server.PeerCount(),
			GasPrice: gasprice,
			Syncing:  syncing,
			Uptime:   100,
		},
	}
	report := map[string][]interface{}{
		"emit": {"stats", stats},
	}
	return out.Encode(report)
}