94 lines
2.3 KiB
Go
94 lines
2.3 KiB
Go
package circolog
|
|
|
|
import (
|
|
"container/ring"
|
|
"time"
|
|
|
|
"gopkg.in/mcuadros/go-syslog.v2/format"
|
|
)
|
|
|
|
// Client represent a client connected via websocket. Its most important field is the messages channel, where
|
|
// new messages are sent.
|
|
type Client struct {
|
|
Messages chan format.LogParts // only hub should write/close this
|
|
LastMsg int // The number of last messages to display
|
|
Nofollow bool // if Nofollow is true, the hub will not keep this client permanently. Rather, it will send every message to "Messages" and close the channel. Use this if you want to get the messages one-shot
|
|
}
|
|
|
|
// The Hub is the central "registry"; it keeps both the data storage and clients notifications
|
|
//
|
|
// The channel "register" and "unregister" can be seen as "command"
|
|
// keep in mind that "registering" is what you do also to get messages in a one-time fashion. In fact, Client
|
|
// has "options", such as Nofollow, to explain the Hub what should be given
|
|
type Hub struct {
|
|
Register chan Client
|
|
Unregister chan Client
|
|
LogMessages chan format.LogParts
|
|
|
|
clients map[Client]bool
|
|
circbuf *ring.Ring
|
|
}
|
|
|
|
// NewHub creates an empty hub
|
|
func NewHub(ringBufSize int) Hub {
|
|
return Hub{clients: make(map[Client]bool),
|
|
Register: make(chan Client),
|
|
Unregister: make(chan Client),
|
|
LogMessages: make(chan format.LogParts),
|
|
circbuf: ring.New(ringBufSize),
|
|
}
|
|
}
|
|
|
|
func (h *Hub) register(cl Client) {
|
|
if _, ok := h.clients[cl]; !ok {
|
|
if !cl.Nofollow { // we won't need it in future
|
|
h.clients[cl] = true
|
|
}
|
|
|
|
circbufDoExit := false
|
|
h.circbuf.Do(func(x interface{}) {
|
|
if circbufDoExit {
|
|
return
|
|
}
|
|
if x != nil {
|
|
select { // send with short timeout
|
|
case cl.Messages <- x.(format.LogParts):
|
|
break
|
|
case <-time.After(500 * time.Millisecond):
|
|
circbufDoExit = true
|
|
break
|
|
}
|
|
}
|
|
})
|
|
if cl.Nofollow {
|
|
close(cl.Messages)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Run is hub main loop; keeps everything going
|
|
func (h *Hub) Run() {
|
|
for {
|
|
select {
|
|
case cl := <-h.Register:
|
|
h.register(cl)
|
|
case cl := <-h.Unregister:
|
|
_, ok := h.clients[cl]
|
|
if ok {
|
|
close(cl.Messages)
|
|
delete(h.clients, cl)
|
|
}
|
|
case msg := <-h.LogMessages:
|
|
h.circbuf.Value = msg
|
|
h.circbuf = h.circbuf.Next()
|
|
for client := range h.clients {
|
|
select { // send without blocking
|
|
case client.Messages <- msg:
|
|
break
|
|
default:
|
|
break
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|