// Copyright 2017 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 dashboard
//go:generate go-bindata -nometadata -o assets.go -prefix assets -pkg dashboard assets/public/...
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"path/filepath"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
"github.com/rcrowley/go-metrics"
"golang.org/x/net/websocket"
)
const (
memorySampleLimit = 200 // Maximum number of memory data samples
trafficSampleLimit = 200 // Maximum number of traffic data samples
)
var nextId uint32 // Next connection id
// Dashboard contains the dashboard internals.
type Dashboard struct {
config *Config
listener net.Listener
conns map[uint32]*client // Currently live websocket connections
charts charts // The collected data samples to plot
lock sync.RWMutex // Lock protecting the dashboard's internals
quit chan chan error // Channel used for graceful exit
wg sync.WaitGroup
}
// message embraces the data samples of a client message.
type message struct {
History *charts `json:"history,omitempty"` // Past data samples
Memory *chartEntry `json:"memory,omitempty"` // One memory sample
Traffic *chartEntry `json:"traffic,omitempty"` // One traffic sample
Log string `json:"log,omitempty"` // One log
}
// client represents active websocket connection with a remote browser.
type client struct {
conn *websocket.Conn // Particular live websocket connection
msg chan message // Message queue for the update messages
logger log.Logger // Logger for the particular live websocket connection
}
// charts contains the collected data samples.
type charts struct {
Memory []*chartEntry `json:"memorySamples,omitempty"`
Traffic []*chartEntry `json:"trafficSamples,omitempty"`
}
// chartEntry represents one data sample
type chartEntry struct {
Time time.Time `json:"time,omitempty"`
Value float64 `json:"value,omitempty"`
}
// New creates a new dashboard instance with the given configuration.
func New(config *Config) (*Dashboard, error) {
return &Dashboard{
conns: make(map[uint32]*client),
config: config,
quit: make(chan chan error),
}, nil
}
// Protocols is a meaningless implementation of node.Service.
func (db *Dashboard) Protocols() []p2p.Protocol { return nil }
// APIs is a meaningless implementation of node.Service.
func (db *Dashboard) APIs() []rpc.API { return nil }
// Start implements node.Service, starting the data collection thread and the listening server of the dashboard.
func (db *Dashboard) Start(server *p2p.Server) error {
db.wg.Add(2)
go db.collectData()
go db.collectLogs() // In case of removing this line change 2 back to 1 in wg.Add.
http.HandleFunc("/", db.webHandler)
http.Handle("/api", websocket.Handler(db.apiHandler))
listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", db.config.Host, db.config.Port))
if err != nil {
return err
}
db.listener = listener
go http.Serve(listener, nil)
return nil
}
// Stop implements node.Service, stopping the data collection thread and the connection listener of the dashboard.
func (db *Dashboard) Stop() error {
// Close the connection listener.
var errs []error
if err := db.listener.Close(); err != nil {
errs = append(errs, err)
}
// Close the collectors.
errc := make(chan error, 1)
for i := 0; i < 2; i++ {
db.quit <- errc
if err := <-errc; err != nil {
errs = append(errs, err)
}
}
// Close the connections.
db.lock.Lock()
for _, c := range db.conns {
if err := c.conn.Close(); err != nil {
c.logger.Warn("Failed to close connection", "err", err)
}
}
db.lock.Unlock()
// Wait until every goroutine terminates.
db.wg.Wait()
log.Info("Dashboard stopped")
var err error
if len(errs) > 0 {
err = fmt.Errorf("%v", errs)
}
return err
}
// webHandler handles all non-api requests, simply flattening and returning the dashboard website.
func (db *Dashboard) webHandler(w http.ResponseWriter, r *http.Request) {
log.Debug("Request", "URL", r.URL)
path := r.URL.String()
if path == "/" {
path = "/dashboard.html"
}
// If the path of the assets is manually set
if db.config.Assets != "" {
blob, err := ioutil.ReadFile(filepath.Join(db.config.Assets, path))
if err != nil {
log.Warn("Failed to read file", "path", path, "err", err)
http.Error(w, "not found", http.StatusNotFound)
return
}
w.Write(blob)
return
}
blob, err := Asset(filepath.Join("public", path))
if err != nil {
log.Warn("Failed to load the asset", "path", path, "err", err)
http.Error(w, "not found", http.StatusNotFound)
return
}
w.Write(blob)
}
// apiHandler handles requests for the dashboard.
func (db *Dashboard) apiHandler(conn *websocket.Conn) {
id := atomic.AddUint32(&nextId, 1)
client := &client{
conn: conn,
msg: make(chan message, 128),
logger: log.New("id", id),
}
done := make(chan struct{}) // Buffered channel as sender may exit early
// Start listening for messages to send.
db.wg.Add(1)
go func() {
defer db.wg.Done()
for {
select {
case <-done:
return
case msg := <-client.msg:
if err := websocket.JSON.Send(client.conn, msg); err != nil {
client.logger.Warn("Failed to send the message", "msg", msg, "err", err)
client.conn.Close()
return
}
}
}
}()
// Send the past data.
client.msg <- message{
History: &db.charts,
}
// Start tracking the connection and drop at connection loss.
db.lock.Lock()
db.conns[id] = client
db.lock.Unlock()
defer func() {
db.lock.Lock()
delete(db.conns, id)
db.lock.Unlock()
}()
for {
fail := []byte{}
if _, err := conn.Read(fail); err != nil {
close(done)
return
}
// Ignore all messages
}
}
// collectData collects the required data to plot on the dashboard.
func (db *Dashboard) collectData() {
defer db.wg.Done()
for {
select {
case errc := <-db.quit:
errc <- nil
return
case <-time.After(db.config.Refresh):
inboundTraffic := metrics.DefaultRegistry.Get("p2p/InboundTraffic").(metrics.Meter).Rate1()
memoryInUse := metrics.DefaultRegistry.Get("system/memory/inuse").(metrics.Meter).Rate1()
now := time.Now()
memory := &chartEntry{
Time: now,
Value: memoryInUse,
}
traffic := &chartEntry{
Time: now,
Value: inboundTraffic,
}
// Remove the first elements in case the samples' amount exceeds the limit.
first := 0
if len(db.charts.Memory) == memorySampleLimit {
first = 1
}
db.charts.Memory = append(db.charts.Memory[first:], memory)
first = 0
if len(db.charts.Traffic) == trafficSampleLimit {
first = 1
}
db.charts.Traffic = append(db.charts.Traffic[first:], traffic)
db.sendToAll(&message{
Memory: memory,
Traffic: traffic,
})
}
}
}
// collectLogs collects and sends the logs to the active dashboards.
func (db *Dashboard) collectLogs() {
defer db.wg.Done()
// TODO (kurkomisi): log collection comes here.
for {
select {
case errc := <-db.quit:
errc <- nil
return
case <-time.After(db.config.Refresh / 2):
db.sendToAll(&message{
Log: "This is a fake log.",
})
}
}
}
// sendToAll sends the given message to the active dashboards.
func (db *Dashboard) sendToAll(msg *message) {
db.lock.Lock()
for _, c := range db.conns {
select {
case c.msg <- *msg:
default:
c.conn.Close()
}
}
db.lock.Unlock()
}
