path: root/ethstats/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 (
    "context"
    "encoding/json"
    "errors"
    "fmt"
    "math/big"
    "net"
    "regexp"
    "runtime"
    "strconv"
    "strings"
    "time"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/common/mclock"
    "github.com/dexon-foundation/dexon/consensus"
    "github.com/dexon-foundation/dexon/core"
    "github.com/dexon-foundation/dexon/core/types"
    "github.com/dexon-foundation/dexon/eth"
    "github.com/dexon-foundation/dexon/event"
    "github.com/dexon-foundation/dexon/les"
    "github.com/dexon-foundation/dexon/log"
    "github.com/dexon-foundation/dexon/p2p"
    "github.com/dexon-foundation/dexon/rpc"
    "golang.org/x/net/websocket"
)

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

    // txChanSize is the size of channel listening to NewTxsEvent.
    // The number is referenced from the size of tx pool.
    txChanSize = 4096
    // chainHeadChanSize is the size of channel listening to ChainHeadEvent.
    chainHeadChanSize = 10
)

type txPool interface {
    // SubscribeNewTxsEvent should return an event subscription of
    // NewTxsEvent and send events to the given channel.
    SubscribeNewTxsEvent(chan<- core.NewTxsEvent) event.Subscription
}

type blockChain interface {
    SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
}

// Service implements an Ethereum netstats reporting daemon that pushes local
// chain statistics up to a monitoring server.
type Service struct {
    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
    engine consensus.Engine   // Consensus engine to retrieve variadic block fields

    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
    var engine consensus.Engine
    if ethServ != nil {
        engine = ethServ.Engine()
    } else {
        engine = lesServ.Engine()
    }
    return &Service{
        eth:    ethServ,
        les:    lesServ,
        engine: engine,
        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()

    log.Info("Stats daemon started")
    return nil
}

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

// loop keeps trying to connect to the netstats server, reporting chain events
// until termination.
func (s *Service) loop() {
    // Subscribe to chain events to execute updates on
    var blockchain blockChain
    var txpool txPool
    if s.eth != nil {
        blockchain = s.eth.BlockChain()
        txpool = s.eth.TxPool()
    } else {
        blockchain = s.les.BlockChain()
        txpool = s.les.TxPool()
    }

    chainHeadCh := make(chan core.ChainHeadEvent, chainHeadChanSize)
    headSub := blockchain.SubscribeChainHeadEvent(chainHeadCh)
    defer headSub.Unsubscribe()

    txEventCh := make(chan core.NewTxsEvent, txChanSize)
    txSub := txpool.SubscribeNewTxsEvent(txEventCh)
    defer txSub.Unsubscribe()

    // Start a goroutine that exhausts the subsciptions to avoid events piling up
    var (
        quitCh = make(chan struct{})
        headCh = make(chan *types.Block, 1)
        txCh   = make(chan struct{}, 1)
    )
    go func() {
        var lastTx mclock.AbsTime

    HandleLoop:
        for {
            select {
            // Notify of chain head events, but drop if too frequent
            case head := <-chainHeadCh:
                select {
                case headCh <- head.Block:
                default:
                }

            // Notify of new transaction events, but drop if too frequent
            case <-txEventCh:
                if time.Duration(mclock.Now()-lastTx) < time.Second {
                    continue
                }
                lastTx = mclock.Now()

                select {
                case txCh <- struct{}{}:
                default:
                }

            // node stopped
            case <-txSub.Err():
                break HandleLoop
            case <-headSub.Err():
                break HandleLoop
            }
        }
        close(quitCh)
    }()
    // Loop reporting until termination
    for {
        // Resolve the URL, defaulting to TLS, but falling back to none too
        path := fmt.Sprintf("%s/api", s.host)
        urls := []string{path}

        if !strings.Contains(path, "://") { // url.Parse and url.IsAbs is unsuitable (https://github.com/golang/go/issues/19779)
            urls = []string{"wss://" + path, "ws://" + path}
        }
        // Establish a websocket connection to the server on any supported URL
        var (
            conf *websocket.Config
            conn *websocket.Conn
            err  error
        )
        for _, url := range urls {
            if conf, err = websocket.NewConfig(url, "http://localhost/"); err != nil {
                continue
            }
            conf.Dialer = &net.Dialer{Timeout: 5 * time.Second}
            if conn, err = websocket.DialConfig(conf); err == nil {
                break
            }
        }
        if err != nil {
            log.Warn("Stats server unreachable", "err", err)
            time.Sleep(10 * time.Second)
            continue
        }
        // Authenticate the client with the server
        if err = s.login(conn); err != nil {
            log.Warn("Stats login failed", "err", err)
            conn.Close()
            time.Sleep(10 * time.Second)
            continue
        }
        go s.readLoop(conn)

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

        for err == nil {
            select {
            case <-quitCh:
                conn.Close()
                return

            case <-fullReport.C:
                if err = s.report(conn); err != nil {
                    log.Warn("Full stats report failed", "err", err)
                }
            case list := <-s.histCh:
                if err = s.reportHistory(conn, list); err != nil {
                    log.Warn("Requested history report failed", "err", err)
                }
            case head := <-headCh:
                if err = s.reportBlock(conn, head); err != nil {
                    log.Warn("Block stats report failed", "err", err)
                }
                if err = s.reportPending(conn); err != nil {
                    log.Warn("Post-block transaction stats report failed", "err", err)
                }
            case <-txCh:
                if err = s.reportPending(conn); err != nil {
                    log.Warn("Transaction stats report failed", "err", 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) {
    // 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 := websocket.JSON.Receive(conn, &msg); err != nil {
            log.Warn("Failed to decode stats server message", "err", err)
            return
        }
        log.Trace("Received message from stats server", "msg", msg)
        if len(msg["emit"]) == 0 {
            log.Warn("Stats server sent non-broadcast", "msg", msg)
            return
        }
        command, ok := msg["emit"][0].(string)
        if !ok {
            log.Warn("Invalid stats server message type", "type", 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
                log.Warn("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 {
                log.Warn("Invalid stats history request", "msg", msg["emit"][1])
                s.histCh <- nil
                continue // Ethstats sometime sends invalid history requests, ignore those
            }
            list, ok := request["list"].([]interface{})
            if !ok {
                log.Warn("Invalid stats history block list", "list", 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 {
                    log.Warn("Invalid stats history block number", "number", num)
                    return
                }
                numbers[i] = uint64(n)
            }
            select {
            case s.histCh <- numbers:
                continue
            default:
            }
        }
        // Report anything else and continue
        log.Info("Unknown stats message", "msg", 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(conn *websocket.Conn) error {
    // Construct and send the login authentication
    infos := s.server.NodeInfo()

    var network, protocol string
    if info := infos.Protocols["eth"]; info != nil {
        network = fmt.Sprintf("%d", info.(*eth.NodeInfo).Network)
        protocol = fmt.Sprintf("eth/%d", eth.ProtocolVersions[0])
    } else {
        network = fmt.Sprintf("%d", infos.Protocols["les"].(*les.NodeInfo).Network)
        protocol = fmt.Sprintf("les/%d", les.ClientProtocolVersions[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 := websocket.JSON.Send(conn, login); err != nil {
        return err
    }
    // Retrieve the remote ack or connection termination
    var ack map[string][]string
    if err := websocket.JSON.Receive(conn, &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(conn *websocket.Conn) error {
    if err := s.reportLatency(conn); err != nil {
        return err
    }
    if err := s.reportBlock(conn, nil); err != nil {
        return err
    }
    if err := s.reportPending(conn); err != nil {
        return err
    }
    if err := s.reportStats(conn); 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(conn *websocket.Conn) 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 := websocket.JSON.Send(conn, 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(5 * time.Second):
        // Ping timeout, abort
        return errors.New("ping timed out")
    }
    latency := strconv.Itoa(int((time.Since(start) / time.Duration(2)).Nanoseconds() / 1000000))

    // Send back the measured latency
    log.Trace("Sending measured latency to ethstats", "latency", latency)

    stats := map[string][]interface{}{
        "emit": {"latency", map[string]string{
            "id":      s.node,
            "latency": latency,
        }},
    }
    return websocket.JSON.Send(conn, stats)
}

// blockStats is the information to report about individual blocks.
type blockStats struct {
    Number     *big.Int       `json:"number"`
    Hash       common.Hash    `json:"hash"`
    ParentHash common.Hash    `json:"parentHash"`
    Timestamp  *big.Int       `json:"timestamp"`
    Miner      common.Address `json:"miner"`
    GasUsed    uint64         `json:"gasUsed"`
    GasLimit   uint64         `json:"gasLimit"`
    Diff       string         `json:"difficulty"`
    TotalDiff  string         `json:"totalDifficulty"`
    Txs        []txStats      `json:"transactions"`
    TxHash     common.Hash    `json:"transactionsRoot"`
    Root       common.Hash    `json:"stateRoot"`
    Uncles     uncleStats     `json:"uncles"`
}

// txStats is the information to report about individual transactions.
type txStats struct {
    Hash common.Hash `json:"hash"`
}

// 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 reports it to the stats server.
func (s *Service) reportBlock(conn *websocket.Conn, block *types.Block) error {
    // Gather the block details from the header or block chain
    details := s.assembleBlockStats(block)

    // Assemble the block report and send it to the server
    log.Trace("Sending new block to ethstats", "number", details.Number, "hash", details.Hash)

    stats := map[string]interface{}{
        "id":    s.node,
        "block": details,
    }
    report := map[string][]interface{}{
        "emit": {"block", stats},
    }
    return websocket.JSON.Send(conn, 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    []txStats
        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 = make([]txStats, len(block.Transactions()))
        for i, tx := range block.Transactions() {
            txs[i].Hash = tx.Hash()
        }
        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())
        txs = []txStats{}
    }
    // Assemble and return the block stats
    author, _ := s.engine.Author(header)

    return &blockStats{
        Number:     header.Number,
        Hash:       header.Hash(),
        ParentHash: header.ParentHash,
        Timestamp:  new(big.Int).SetUint64(header.Time),
        Miner:      author,
        GasUsed:    header.GasUsed,
        GasLimit:   header.GasLimit,
        Diff:       header.Difficulty.String(),
        TotalDiff:  td.String(),
        Txs:        txs,
        TxHash:     header.TxHash,
        Root:       header.Root,
        Uncles:     uncles,
    }
}

// reportHistory retrieves the most recent batch of blocks and reports it to the
// stats server.
func (s *Service) reportHistory(conn *websocket.Conn, 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 int64
        if s.eth != nil {
            head = s.eth.BlockChain().CurrentHeader().Number.Int64()
        } else {
            head = s.les.BlockChain().CurrentHeader().Number.Int64()
        }
        start := head - historyUpdateRange + 1
        if start < 0 {
            start = 0
        }
        for i := uint64(start); i <= uint64(head); i++ {
            indexes = append(indexes, i)
        }
    }
    // Gather the batch of blocks to report
    history := make([]*blockStats, len(indexes))
    for i, number := range indexes {
        // Retrieve the next block if it's known to us
        var block *types.Block
        if s.eth != nil {
            block = s.eth.BlockChain().GetBlockByNumber(number)
        } else {
            if header := s.les.BlockChain().GetHeaderByNumber(number); header != nil {
                block = types.NewBlockWithHeader(header)
            }
        }
        // If we do have the block, add to the history and continue
        if block != nil {
            history[len(history)-1-i] = s.assembleBlockStats(block)
            continue
        }
        // Ran out of blocks, cut the report short and send
        history = history[len(history)-i:]
        break
    }
    // Assemble the history report and send it to the server
    if len(history) > 0 {
        log.Trace("Sending historical blocks to ethstats", "first", history[0].Number, "last", history[len(history)-1].Number)
    } else {
        log.Trace("No history to send to stats server")
    }
    stats := map[string]interface{}{
        "id":      s.node,
        "history": history,
    }
    report := map[string][]interface{}{
        "emit": {"history", stats},
    }
    return websocket.JSON.Send(conn, 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(conn *websocket.Conn) 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
    log.Trace("Sending pending transactions to ethstats", "count", pending)

    stats := map[string]interface{}{
        "id": s.node,
        "stats": &pendStats{
            Pending: pending,
        },
    }
    report := map[string][]interface{}{
        "emit": {"pending", stats},
    }
    return websocket.JSON.Send(conn, report)
}

// nodeStats 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(conn *websocket.Conn) 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

        price, _ := s.eth.APIBackend.SuggestPrice(context.Background())
        gasprice = int(price.Uint64())
    } else {
        sync := s.les.Downloader().Progress()
        syncing = s.les.BlockChain().CurrentHeader().Number.Uint64() >= sync.HighestBlock
    }
    // Assemble the node stats and send it to the server
    log.Trace("Sending node details to ethstats")

    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 websocket.JSON.Send(conn, report)
}