/**
* process subscriber commands
* when feed command is received, data must be received within 30 seconds or subscriber will unsubscribe
*/
func (s *Subscriber) subscriberCommandProcess(h *Hub) {
l.If("subscriber process - %s - start", s.id)
defer l.If("subscriber process - %s - end", s.id)
for {
select {
case subscriberCommand := <-s.commandListener:
switch subscriberCommand.command {
case SubscriberStop:
l.If("subscriber process - %s - stop", s.id)
return
case SubscriberFeed:
l.If("subscriber process - %s - feed", s.id)
select {
case s.feedListener <- subscriberCommand.SubscriberFeedCommand:
case <-time.After(30 * time.Second):
l.Wf("subscriber process - %s - feed timedout", s.id)
h.subscriberCommandListener <- HubSubscriberRequest{Unsubscribe, s.id, nil, nil}
return
}
}
case <-time.After(30 * time.Second):
l.If("subscriber process - %s - alive", s.id)
}
}
}
func NewHubRepository() *HubRepository {
var repository = new(HubRepository)
repository.channels = make(map[string]*Channel)
repository.getChannelListener = make(chan HubRepositoryChannelGetCommand, expectedMaxSubscribers)
repository.newDataListener = make(map[string]chan ChannelDataInputCommand, expectedMaxSubscribers)
repository.getDataListener = make(map[string]chan ChannelDataRequestCommand, expectedMaxSubscribers)
if restoreData {
l.I("restoring channels")
// read previous data
var files, err = ioutil.ReadDir("data")
if err == nil {
for i := 0; i < len(files); i++ {
var file = files[i]
if !strings.HasSuffix(file.Name(), ".json") {
continue
}
var data, err = ioutil.ReadFile("data/" + file.Name())
if err == nil {
l.If("restoring channel %s", file.Name())
var channel = new(Channel)
var err = json.Unmarshal(data, channel)
if err == nil && strings.Trim(channel.ChannelName, "") != "" {
repository.addCreatedChannel(channel)
}
}
}
}
l.I("restoring channels completed.")
}
// start channel process
go repository.channelProcess()
return repository
}
/**
* Http request handler
*/
func (h *Hub) ServeHTTP(w http.ResponseWriter, r *http.Request) {
defer func() {
if x := recover(); x != nil {
l.Ef("request %s caused error from %s {%s}: %v", r.URL.Path, r.RemoteAddr, r.Form.Encode(), x)
}
}()
w.Header().Set("Access-Control-Allow-Origin", "*")
parts := strings.Split(r.URL.Path, "/")
command := parts[1]
r.ParseForm()
startTime := time.Now()
l.If("http serving request %s from %s {%s}", r.URL.Path, r.RemoteAddr, r.Form.Encode())
mediator := HttpDataMediator{w: w, r: r}
h.route(command, &mediator)
delay := float64(time.Now().Sub(startTime).Nanoseconds()) / 1000000.0
l.If("http Served request %s from %s {%s} took %f ms", r.URL.Path, r.RemoteAddr, r.Form.Encode(), delay)
}
func (m *WebSocketHandler) reader() {
l.I("wsreader process - starting")
var subscriberId string = "anonymous"
for {
var message string
err := websocket.Message.Receive(m.ws, &message)
if err != nil {
l.If("wsreader process - %s - error reading from socket: %s", subscriberId, err.Error())
break
}
l.If("wsreader process - read from socket %s", string(message))
var command = new(WebSocketCommand)
err = json.Unmarshal([]byte(message), command)
if err != nil {
l.Ef("wsreader process - %s - error unmarshal commad %s", subscriberId, err.Error())
break
}
var mediator = WebSocketDataMediator{send: m.send, command: *command, RequestId: command.RequestId}
// special commands - keep alive and subscribe
if command.Command == "keepAlive" {
var subscriber = m.hub.subscribers[m.subscriber.id]
// subscriber not found
if subscriber == nil {
l.Wf("wsreader process - %s - timed out!", subscriberId)
break
} else {
subscriber.lastRequest = time.Now().Unix()
}
} else if command.Command == "subscribe" {
var channels = strings.Split(mediator.ReadParameter("channels"), ",")
var responseListener = make(chan Subscriber)
m.hub.subscriberCommandListener <- HubSubscriberRequest{command: Subscribe, channels: channels, responseListener: responseListener}
m.subscriber = <-responseListener
subscriberId = m.subscriber.id
go m.writer()
mediator.WriteResponse(map[string]interface{}{"command": "subscribe", "subscriberId": m.subscriber.id}, "json")
close(responseListener)
} else {
m.hub.route(command.Command, &mediator)
}
}
m.closeListener <- true
l.If("wsreader process - %s - stopped", subscriberId)
m.ws.Close()
}
func (r *HubRepository) channelProcess() {
l.I("channels process - start")
for {
var channelRequest = <-r.getChannelListener
var channel = r.channels[channelRequest.channelName]
if channel == nil {
l.If("channels process - add channel %s", channelRequest.channelName)
channel = new(Channel)
channel.ChannelName = channelRequest.channelName
channel.DataVersion = 0
channel.Data = ""
r.addCreatedChannel(channel)
}
l.If("channels process - served channel %s", channelRequest.channelName)
channelRequest.resultListener <- HubRepositoryChannelFeeds{newDataListener: r.newDataListener[channel.ChannelName], getDataListener: r.getDataListener[channel.ChannelName]}
}
l.I("channels process - end")
}
func main() {
path, err := os.Getwd()
if err != nil {
panic(err)
}
l.If("current app path: %s", path)
var processes = runtime.NumCPU()
runtime.GOMAXPROCS(processes)
l.If("using processes %d", processes)
l.I("server started.")
restartLisnener := make(chan string)
hub := comet.NewHub()
for {
go httpServerProcess(hub, restartLisnener)
reason := <-restartLisnener
l.Wf("web server restarted: %s", reason)
}
}
func httpServerProcess(hub *comet.Hub, restartListener chan string) {
var ip = flag.String("ip", "0.0.0.0", "ip address to listen on")
var port = flag.Int("port", 8080, "port to listen on")
flag.Parse()
var addr = fmt.Sprintf("%s:%d", *ip, *port)
l.If("listening on %s", addr)
http.HandleFunc("/", hub.ServeHTTP)
http.Handle("/ws", websocket.Handler(hub.ServeWebsocket))
err := http.ListenAndServe(addr, nil)
restartListener <- err.Error()
}
func (h *Hub) createSubscriber(channels []string) Subscriber {
l.If("subscriber creating with channels %s", channels)
var id, err = newUUID()
if err != nil {
l.Ef("Error creation new uuid %s", err.Error())
}
subscriber := Subscriber{
id: id,
commandListener: make(chan SubscriberControlCommand, 10),
feedListener: make(chan SubscriberFeedCommand, subscriberQueueSize),
channels: make(map[string]*SubscriberChannel),
}
channels = append(channels, fmt.Sprintf("private_%s", id))
h.addChannelsToSubscriber(channels, &subscriber)
subscriber.lastRequest = time.Now().Unix()
go subscriber.subscriberCommandProcess(h)
h.subscribers[id] = &subscriber
l.If("subscriber %s created with channels %s", id, channels)
return subscriber
}
func (m *WebSocketHandler) writer() {
l.If("wswriter process - %s - starting", m.subscriber.id)
defer close(m.send)
defer close(m.closeListener)
defer m.ws.Close()
defer l.If("wswriter process - %s - stopped", m.subscriber.id)
for {
select {
case message := <-m.send:
jsonData, _ := json.Marshal(message)
l.If("wswriter process - %s - serve json %s", m.subscriber.id, jsonData)
err := websocket.Message.Send(m.ws, string(jsonData))
if err != nil {
l.Ef("wswriter process - %s - error writing to socket: %s", m.subscriber.id, err.Error())
}
case command := <-m.subscriber.feedListener:
var response = SubscriberResponse{Status: 1, Commands: command.data}
jsonData, _ := json.Marshal(response)
l.If("wswriter process - %s - serve data: %s", m.subscriber.id, string(jsonData))
err := websocket.Message.Send(m.ws, string(jsonData))
if err != nil {
l.Ef("wswriter process - %s - error writing to socket: %s", m.subscriber.id, err.Error())
}
case <-m.closeListener:
l.If("wswriter process - %s - received close command", m.subscriber.id)
return
case <-time.After(30 * time.Second):
l.If("wswriter process - %s - alive", m.subscriber.id)
}
}
}
/**
* receive and feed data from a channel
**/
func (r *HubRepository) dataProcess(channelName string) {
l.If("data process - %s - start", channelName)
for {
select {
// on new data
case newData := <-r.newDataListener[channelName]:
l.If("data process - %s - new data: %s ", channelName, newData.ToJson())
var channel = r.channels[newData.ChannelName]
if channel == nil {
channel = new(Channel)
channel.ChannelName = newData.ChannelName
channel.DataVersion = 0
channel.Data = ""
r.channels[newData.ChannelName] = channel
}
channel.addNewData(DataOperation(newData.Command), newData.Data, newData.responseListener)
if !strings.HasPrefix("private", channel.ChannelName) {
// persist data
var js, _ = json.Marshal(channel)
var err = ioutil.WriteFile("data/"+channel.ChannelName+".json", js, 0644)
if err != nil {
log.Panic(err)
}
}
// on data feed request
case newRequest := <-r.getDataListener[channelName]:
l.If("data process - %s - get data", channelName)
var channel = r.channels[newRequest.channelName]
var result Channel
if channel == nil {
result = Channel{newRequest.channelName, 0, "", time.Now(), make([]ChannelData, 0)}
} else {
result = channel.Copy()
}
newRequest.responseReceiver <- result
}
}
l.If("data process - %s - stop", channelName)
}
/**
* handles adding, removing, cleaning and feeding subscribers
*/
func (h *Hub) subscribersProcess() {
l.I("subscribers process - starting")
for {
select {
case newData := <-h.subscriberFeedListener:
l.If("subscribers process - newData", newData)
for _, subscriber := range h.subscribers {
if subscriber.channels[newData.channelData.ChannelName] != nil {
select {
case subscriber.commandListener <- SubscriberControlCommand{SubscriberFeed, CreateSingleFeedCommad(string(newData.operation), newData.channelData.ChannelName, newData.channelData.Data, newData.channelData.DataVersion)}:
default:
l.Wf("subscribers process - did not deliver new data to %s - queue full", subscriber.id)
}
}
}
case subscriberCommand := <-h.subscriberCommandListener:
switch subscriberCommand.command {
case Subscribe:
l.I("subscribers process - subscribe")
newSubscriber := h.createSubscriber(subscriberCommand.channels)
subscriberCommand.responseListener <- newSubscriber
case Unsubscribe:
l.If("subscribers process - %s - unsubscribe", subscriberCommand.subscriberId)
h.deleteSubscriber(subscriberCommand.subscriberId)
subscriberCommand.responseListener <- Subscriber{}
case SubscribeToChannels:
l.If("subscribers process - %s - subscribe to channels", subscriberCommand.subscriberId, subscriberCommand.channels)
if subscriber, found := h.subscribers[subscriberCommand.subscriberId]; found == true {
h.addChannelsToSubscriber(subscriberCommand.channels, subscriber)
subscriberCommand.responseListener <- *subscriber
} else {
subscriberCommand.responseListener <- Subscriber{}
}
case UnsubscribeFromChannels:
l.If("subscribers process - %s - unsubscribe from channels", subscriberCommand.subscriberId, subscriberCommand.channels)
if subscriber, found := h.subscribers[subscriberCommand.subscriberId]; found == true {
h.removeChannelsFromSubscriber(subscriberCommand.channels, subscriber)
subscriberCommand.responseListener <- *subscriber
} else {
subscriberCommand.responseListener <- Subscriber{}
}
case CleanupSubscribers:
var cleanupStartTime = time.Now().Unix()
for id, subscriber := range h.subscribers {
if cleanupStartTime-subscriber.lastRequest > secondsToKeepSubscriberAlive {
l.If("subscribers process - found dead subscriber %s", id)
h.deleteSubscriber(id)
}
}
}
case <-time.After(30 * time.Second):
l.If("subscribers process - alive")
}
}
l.I("subscribers process - stopped")
}