/
streams.go
113 lines (100 loc) · 2.66 KB
/
streams.go
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package server
import (
pb "github.com/supermihi/karlchencloud/api"
u "github.com/supermihi/karlchencloud/server/users"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"log"
"sync"
)
type eventStream chan *pb.Event
type ClientStream struct {
events eventStream
kicked chan int
}
type ClientStreams struct {
mtx sync.RWMutex
clients map[u.Id]ClientStream
}
func NewClientStreams() ClientStreams {
return ClientStreams{clients: make(map[u.Id]ClientStream)}
}
// SendSingle synchronously sends an event to a single user stream.
func (cs *ClientStreams) SendSingle(user u.Id, event *pb.Event) {
cs.mtx.RLock()
client, ok := cs.clients[user]
if ok {
client.events <- event
}
cs.mtx.RUnlock()
}
// Send synchronously sends an event to a list of users.
func (cs *ClientStreams) Send(users []u.Id, event *pb.Event) {
for _, user := range users {
cs.SendSingle(user, event)
}
}
func (cs *ClientStreams) StartNew(srv pb.Doko_StartSessionServer, user u.Id) chan int {
client := cs.createStream(user)
go func() {
for {
select {
case <-srv.Context().Done():
log.Printf("no longer waiting for messages to %s", user)
cs.onStreamEndedByClient(user)
return
case event, ok := <-client.events:
if !ok {
log.Printf("client kicked, returning stream loop")
return
}
if s, sendOk := status.FromError(srv.Send(event)); sendOk {
switch s.Code() {
case codes.OK:
// pass
case codes.Unavailable, codes.Canceled, codes.DeadlineExceeded:
log.Printf("client %s terminated connection", user)
cs.onStreamEndedByClient(user)
return
default:
log.Printf("failed to Send to client %s: %v", user, s.Err())
}
} else {
log.Printf("unknonw error: %s", s.Err())
}
}
}
}()
return client.kicked
}
const userStreamBufferSize = 10
func (cs *ClientStreams) createStream(user u.Id) ClientStream {
cs.mtx.Lock()
defer cs.mtx.Unlock()
if existingClient, exists := cs.clients[user]; exists {
delete(cs.clients, user)
close(existingClient.events)
close(existingClient.kicked)
log.Printf("kicked %s because she started a new session", user)
}
client := ClientStream{events: make(eventStream, userStreamBufferSize),
kicked: make(chan int)}
cs.clients[user] = client
return client
}
func (cs *ClientStreams) onStreamEndedByClient(user u.Id) {
cs.mtx.Lock()
if client, exists := cs.clients[user]; exists {
delete(cs.clients, user)
close(client.events)
close(client.kicked)
log.Printf("closed table stream for %s", user)
}
cs.mtx.Unlock()
}
func (cs *ClientStreams) IsOnline(user u.Id) bool {
cs.mtx.RLock()
defer cs.mtx.RUnlock()
_, ok := cs.clients[user]
return ok
}