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loop.go
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loop.go
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package socket
import (
"encoding/json"
"errors"
"net/http"
"net/url"
"sync"
"time"
"github.com/replicatedhq/kots/pkg/socket/protocol"
"github.com/replicatedhq/kots/pkg/socket/transport"
)
const (
queueBufferSize = 500
)
var (
ErrorWrongHeader = errors.New("Wrong header")
)
/**
engine.io header to send or receive
*/
type Header struct {
Sid string `json:"sid"`
Upgrades []string `json:"upgrades"`
PingInterval int `json:"pingInterval"`
PingTimeout int `json:"pingTimeout"`
}
/**
socket.io connection handler
use IsAlive to check that handler is still working
use Dial to connect to websocket
use In and Out channels for message exchange
Close message means channel is closed
ping is automatic
*/
type Channel struct {
conn transport.Connection
out chan string
header Header
alive bool
aliveLock sync.Mutex
ack ackProcessor
server *Server
ip string
requestHeader http.Header
requestURL *url.URL
}
/**
create channel, map, and set active
*/
func (c *Channel) initChannel() {
//TODO: queueBufferSize from constant to server or client variable
c.out = make(chan string, queueBufferSize)
c.ack.resultWaiters = make(map[int](chan string))
c.alive = true
}
/**
Get id of current socket connection
*/
func (c *Channel) Id() string {
return c.header.Sid
}
/**
Checks that Channel is still alive
*/
func (c *Channel) IsAlive() bool {
c.aliveLock.Lock()
defer c.aliveLock.Unlock()
return c.alive
}
/**
Close channel
*/
func closeChannel(c *Channel, m *methods, args ...interface{}) error {
c.aliveLock.Lock()
defer c.aliveLock.Unlock()
if !c.alive {
//already closed
return nil
}
c.conn.Close()
c.alive = false
//clean outloop
for len(c.out) > 0 {
<-c.out
}
c.out <- protocol.CloseMessage
m.callLoopEvent(c, OnDisconnection)
overfloodedLock.Lock()
delete(overflooded, c)
overfloodedLock.Unlock()
return nil
}
//incoming messages loop, puts incoming messages to In channel
func inLoop(c *Channel, m *methods) error {
for {
pkg, err := c.conn.GetMessage()
if err != nil {
return closeChannel(c, m, err)
}
msg, err := protocol.Decode(pkg)
if err != nil {
closeChannel(c, m, protocol.ErrorWrongPacket)
return err
}
switch msg.Type {
case protocol.MessageTypeOpen:
if err := json.Unmarshal([]byte(msg.Source[1:]), &c.header); err != nil {
closeChannel(c, m, ErrorWrongHeader)
}
m.callLoopEvent(c, OnConnection)
case protocol.MessageTypePing:
c.out <- protocol.PongMessage
case protocol.MessageTypePong:
default:
go m.processIncomingMessage(c, msg)
}
}
}
var overflooded map[*Channel]struct{} = make(map[*Channel]struct{})
var overfloodedLock sync.Mutex
func AmountOfOverflooded() int64 {
overfloodedLock.Lock()
defer overfloodedLock.Unlock()
return int64(len(overflooded))
}
/**
outgoing messages loop, sends messages from channel to socket
*/
func outLoop(c *Channel, m *methods) error {
for {
outBufferLen := len(c.out)
if outBufferLen >= queueBufferSize-1 {
return closeChannel(c, m, ErrorSocketOverflood)
} else if outBufferLen > int(queueBufferSize/2) {
overfloodedLock.Lock()
overflooded[c] = struct{}{}
overfloodedLock.Unlock()
} else {
overfloodedLock.Lock()
delete(overflooded, c)
overfloodedLock.Unlock()
}
msg := <-c.out
if msg == protocol.CloseMessage {
return nil
}
err := c.conn.WriteMessage(msg)
if err != nil {
return closeChannel(c, m, err)
}
}
}
/**
Pinger sends ping messages for keeping connection alive
*/
func pinger(c *Channel) {
for {
interval, _ := c.conn.PingParams()
time.Sleep(interval)
if !c.IsAlive() {
return
}
c.out <- protocol.PingMessage
}
}