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viz.go
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viz.go
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package core
import (
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"time"
"github.com/gorilla/mux"
log "github.com/inconshreveable/log15"
"github.com/joonnna/ifrit/netutil"
"github.com/rs/cors"
)
const (
httpPort = 12300
)
type viz struct {
n *Node
l net.Listener
httpServer *http.Server
httpAddr string
trusted bool
id string
addr string
updateTimeout time.Duration
exitChan chan bool
}
type state struct {
ID string
Next string
Prev string
HttpAddr string
Trusted bool
}
func (s state) equal(other *state) bool {
return (s.Next == other.Next && s.Prev == other.Prev)
}
func (s *state) marshal() io.Reader {
buff := new(bytes.Buffer)
json.NewEncoder(buff).Encode(s)
return bytes.NewReader(buff.Bytes())
}
func newViz(n *Node, vizAddr string, updateInterval time.Duration, trusted bool) (*viz, error) {
l, err := netutil.ListenOnPort(httpPort)
if err != nil {
return nil, err
}
v := &viz{
updateTimeout: updateInterval,
n: n,
addr: vizAddr,
exitChan: make(chan bool, 1),
httpAddr: l.Addr().String(),
trusted: trusted,
}
log.Debug("http addr", "addr", v.httpAddr)
r := mux.NewRouter()
r.HandleFunc("/shutdownNode", v.shutdownHandler)
r.HandleFunc("/byzantine", v.byzantineHandler)
handler := cors.Default().Handler(r)
v.httpServer = &http.Server{
Handler: handler,
}
v.l = l
return v, nil
}
func (v *viz) start() error {
v.addToViz()
go v.updateState()
return v.httpServer.Serve(v.l)
}
func (v *viz) stop() {
v.remove()
v.httpServer.Close()
close(v.exitChan)
}
func (v *viz) byzantineHandler(w http.ResponseWriter, r *http.Request) {
io.Copy(ioutil.Discard, r.Body)
r.Body.Close()
log.Info("Got byzantine request, periodically not responding to pings!")
go v.periodicallyPause(time.Second * 20)
}
func (v *viz) shutdownHandler(w http.ResponseWriter, r *http.Request) {
io.Copy(ioutil.Discard, r.Body)
r.Body.Close()
log.Info("Received shutdown request!")
go v.n.Stop()
}
func (v *viz) periodicallyPause(d time.Duration) {
for {
select {
case <-v.exitChan:
return
default:
v.n.fd.stopServing(d)
}
time.Sleep(d * 3)
}
}
/* Periodically sends the nodes current state to the state server */
func (v *viz) updateState() {
var i uint32
client := &http.Client{}
rings := v.n.view.NumRings()
prevStates := make([]*state, 0, rings)
for i = 0; i < rings; i++ {
prevStates = append(prevStates, &state{})
}
for {
select {
case <-v.exitChan:
return
case <-time.After(v.updateTimeout):
for i = 1; i <= rings; i++ {
s := v.newState(i)
idx := i - 1
if prevStates[idx].equal(s) {
continue
}
prevStates[idx] = s
v.updateReq(s.marshal(), client)
}
}
}
}
/* Creates a new state */
func (v *viz) newState(ringId uint32) *state {
var succId, prevId string
succ, prev := v.n.view.MyRingNeighbours(ringId)
if succ != nil {
succId = fmt.Sprintf("%s|%d", succ.Addr, ringId)
}
if prev != nil {
prevId = fmt.Sprintf("%s|%d", prev.Addr, ringId)
}
return &state{
ID: fmt.Sprintf("%s|%d", v.n.self.Addr, ringId),
Next: succId,
Prev: prevId,
HttpAddr: v.httpAddr,
Trusted: v.trusted,
}
}
/* Sends the node state to the state server*/
func (v *viz) updateReq(r io.Reader, c *http.Client) {
addr := fmt.Sprintf("http://%s/update", v.addr)
req, err := http.NewRequest("POST", addr, r)
if err != nil {
log.Error(err.Error())
return
}
resp, err := c.Do(req)
if err != nil {
log.Error(err.Error())
} else {
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}
}
/* Sends a post request to the state server add endpoint */
func (v *viz) addToViz() {
var i uint32
addr := fmt.Sprintf("http://%s/add", v.addr)
for i = 1; i <= v.n.view.NumRings(); i++ {
s := v.newState(i)
req, err := http.NewRequest("POST", addr, s.marshal())
if err != nil {
log.Error(err.Error())
continue
}
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
log.Error(err.Error())
} else {
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}
}
}
func (v *viz) remove() {
removeMsg := struct {
HttpAddr string
}{
v.httpAddr,
}
buff := new(bytes.Buffer)
json.NewEncoder(buff).Encode(removeMsg)
addr := fmt.Sprintf("http://%s/remove", v.addr)
req, err := http.NewRequest("POST", addr, bytes.NewReader(buff.Bytes()))
if err != nil {
log.Error(err.Error())
return
}
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
log.Error(err.Error())
} else {
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}
}