ODWRTW/canape
2
2
Fork 0
Code Issues 3 Pull Requests 1 Releases Activity

Fix deadlock in channels

Browse Source 
We now close the Channels when its connection is closed so that we never
try to send events into a dead channel
Add a debug handler showing who is subscribed to what
This commit is contained in:
Lucas BEE 2019-07-17 12:16:06 +00:00
parent f48292e8e4
commit 07823efd74
6 changed files with 62 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
backend/events/channel.go
View File

@ -22,11 +22,12 @@ type Channel struct {
// Underlying ws connection
conn *websocket.Conn
// A channel is directly linked to a user
User *models.User
User *models.User `json:"user"`
// List of events the user is listening to
events map[string]struct{}
Events map[string]struct{} `json:"events"`
ID string `json:"id"`
db *sqlx.DB
id string
closed bool
}
// go routine writing events to the websocket connection
@ -110,7 +111,7 @@ func (c *Channel) reader() {
switch msg.Type {
case "subscribe":
c.log.Debugf("subscribe to %s", msg.Message)
if _, ok := c.events[e.Name]; ok {
if _, ok := c.Events[e.Name]; ok {
c.log.Infof("user %s is already subscribed to %s", c.User.Name, e.Name)
continue
}
@ -118,10 +119,10 @@ func (c *Channel) reader() {
c.Error(e.Name, err)
continue
}
c.events[e.Name] = struct{}{}
c.Events[e.Name] = struct{}{}
case "unsubscribe":
c.log.Debugf("unsubscribe from %s", msg.Message)
if _, ok := c.events[e.Name]; !ok {
if _, ok := c.Events[e.Name]; !ok {
c.log.Infof("user %s is not subscribed to %s", c.User.Name, e.Name)
continue
}
@ -133,16 +134,23 @@ func (c *Channel) reader() {
}
func (c *Channel) close() {
// Unsubscribe from all events
for eventName := range c.events {
// The channel is now closed
c.closed = true
// Unsubscribe from all Events
for eventName := range c.Events {
Eventers[eventName].Unsubscribe(c)
}
// Tell the writer to stop
c.done <- struct{}{}
}
// Error sends an error into the errorStream channel
func (c *Channel) Error(name string, err error) {
if c.closed {
return
}
c.log.WithField("name", name).Warn(err)
c.serverErrorStream <- ServerError{
Event: Event{
@ -158,6 +166,9 @@ func (c *Channel) Error(name string, err error) {
// FatalError sends an error into the errorStream channel
func (c *Channel) FatalError(name string, err error) {
if c.closed {
return
}
c.log.WithField("name", name).Warn(err)
c.serverErrorStream <- ServerError{
Event: Event{
@ -171,6 +182,14 @@ func (c *Channel) FatalError(name string, err error) {
}
}
// SendEvent sends an event to the serverEvent channel
func (c *Channel) sendEvent(event ServerEvent) {
if c.closed {
return
}
c.serverEventStream <- event
}
// Unsubscribe unsubscribes a user from all eventers
func Unsubscribe(u *models.User) {
chanl := &Channel{User: u}

1
backend/events/events.go
View File

@ -55,4 +55,5 @@ type Eventer interface {
NotifyAll(data interface{})
Launch() error
Finish()
FatalError(error)
}

22
backend/events/handlers.go
View File

@ -70,8 +70,9 @@ func WsHandler(env *web.Env, w http.ResponseWriter, r *http.Request) error {
log: env.Log,
User: user,
db: env.Database,
events: map[string]struct{}{},
id: requestID,
Events: map[string]struct{}{},
ID: requestID,
closed: false,
}
// Launch the go routine responsible for writing events in the websocket
@ -87,7 +88,7 @@ func PolochonHookHandler(env *web.Env, w http.ResponseWriter, r *http.Request) e
vars := mux.Vars(r)
id := vars["id"]
token := r.URL.Query().Get("token")
env.Log.Infof("Got call on hook with %s and %s", id, token)
env.Log.Infof("got call on hook with %s and %s", id, token)
// Get the polochon associated
p, err := models.GetPolochonByID(env.Database, id)
@ -118,3 +119,18 @@ func PolochonHookHandler(env *web.Env, w http.ResponseWriter, r *http.Request) e
return env.RenderOK(w, "All good")
}
// HookDebugHandler handles the websockets messages
func HookDebugHandler(env *web.Env, w http.ResponseWriter, r *http.Request) error {
debug := map[string]map[string][]*Channel{}
for e, event := range Eventers {
debug[e] = map[string][]*Channel{}
for poloName, polo := range event.polochons {
debug[e][poloName] = polo.Subscribers()
}
}
return env.RenderJSON(w, debug)
}

23
backend/events/polochons.go
View File

@ -55,7 +55,7 @@ func (p *PolochonEventers) Subscribe(chanl *Channel) error {
// listening
tn, ok := p.polochons[chanl.User.PolochonID.String]
if !ok {
p.log.Debugf("Eventer not already created, create it for polochon %s", chanl.User.PolochonID.String)
p.log.Debugf("create new eventer for polochon %s", chanl.User.PolochonID.String)
// Get the user's polochon
polo, err := chanl.User.GetPolochon(chanl.db)
@ -71,6 +71,7 @@ func (p *PolochonEventers) Subscribe(chanl *Channel) error {
go func() {
err := tn.Launch()
if err != nil {
tn.FatalError(err)
delete(p.polochons, chanl.User.PolochonID.String)
}
}()
@ -81,7 +82,7 @@ func (p *PolochonEventers) Subscribe(chanl *Channel) error {
// Add the Channel to the Eventer
tn.Append(chanl)
p.log.Debugf("Eventer created for polochon %s ...", chanl.User.PolochonID.String)
p.log.Debugf("eventer created for polochon %s", chanl.User.PolochonID.String)
return nil
}
@ -96,14 +97,14 @@ func (p *PolochonEventers) Unsubscribe(chanl *Channel) {
tn, ok := p.polochons[chanl.User.PolochonID.String]
if !ok {
p.log.Warnf("no Eventer for polochon %s, not unsubscribing", chanl.User.PolochonID.String)
p.log.Warnf("no eventer for polochon %s, not unsubscribing", chanl.User.PolochonID.String)
return
}
tn.Unsubscribe(chanl)
if len(tn.Subscribers()) == 0 {
p.log.Debugf("just deleted the last user of this polochon instance, delete it")
p.log.Debugf("empty subscribers for this polochon, delete it")
tn.Finish()
// Delete the polochon from the Eventer when it's finished
delete(p.polochons, chanl.User.PolochonID.String)
@ -124,15 +125,15 @@ func (e *BaseEventer) Unsubscribe(chanl *Channel) error {
// Ugly ...
// If we don't have a channel ID, check the user ID
// Else check for the channel ID
if (chanl.id == "" && e.users[i].User.ID != chanl.User.ID) ||
(chanl.id != "" && e.users[i].id != chanl.id) {
if (chanl.ID == "" && e.users[i].User.ID != chanl.User.ID) ||
(chanl.ID != "" && e.users[i].ID != chanl.ID) {
i++
continue
}
e.log.Debugf("found the user channel %s for user %s, deleting it...", chanl.id, chanl.User.Name)
e.log.Debugf("found the user channel %s for user %s, deleting it...", chanl.ID, chanl.User.Name)
// Delete this event from the list of events the channel is subscribed
delete(e.users[i].events, e.name)
delete(e.users[i].Events, e.name)
// Send the disconnected event
event := ServerEvent{
@ -142,7 +143,7 @@ func (e *BaseEventer) Unsubscribe(chanl *Channel) error {
},
}
e.users[i].serverEventStream <- event
e.users[i].sendEvent(event)
// Replace the current element with the last one
e.users[i] = e.users[len(e.users)-1]
@ -160,7 +161,7 @@ func (e *BaseEventer) FatalError(err error) {
// Send the error
chanl.FatalError(e.name, err)
// Delete the event from the channel events
delete(chanl.events, e.name)
delete(chanl.Events, e.name)
}
}
@ -188,6 +189,6 @@ func (e *BaseEventer) NotifyAll(data interface{}) {
// Send the events to all the subscribed users
for _, chanl := range e.users {
e.log.Debugf("sending event to %s", chanl.User.Name)
chanl.serverEventStream <- event
chanl.sendEvent(event)
}
}

9
backend/events/torrent_eventer.go
View File

@ -33,8 +33,7 @@ func NewTorrentEventer(polo *models.Polochon, log *logrus.Entry) (Eventer, error
// Create a new papi client
client, err := polo.NewPapiClient()
if err != nil {
log.Warnf("failed to create the polochon client %s", err)
return nil, fmt.Errorf("failed to instanciate polochon client")
return nil, fmt.Errorf("failed to instanciate polochon client %s", err)
}
// This is the first time this polochon is requested, create the TorrentEventer
@ -64,7 +63,7 @@ func (t *TorrentEventer) Append(chanl *Channel) {
Data: t.torrents,
}
chanl.serverEventStream <- event
chanl.sendEvent(event)
t.BaseEventer.Append(chanl)
}
@ -78,8 +77,6 @@ func (t *TorrentEventer) Launch() error {
err := t.torrentsUpdate()
if err != nil {
t.log.Warnf("got error getting torrent update: %s", err)
t.FatalError(err)
return err
}
@ -88,8 +85,6 @@ func (t *TorrentEventer) Launch() error {
case <-timeTicker.C:
err := t.torrentsUpdate()
if err != nil {
t.log.Warnf("got error getting torrent update: %s", err)
t.FatalError(err)
return err
}
case <-t.done:

1
backend/routes.go
View File

@ -82,6 +82,7 @@ func setupRoutes(env *web.Env) {
// Route to handle websocket events
env.Handle("/events/polochons/{id}/hook", events.PolochonHookHandler).Methods("POST")
env.Handle("/events/debug", events.HookDebugHandler).WithRole(models.AdminRole).Methods("GET")
// Admin routes
env.Handle("/admins/users", admin.GetUsersHandler).WithRole(models.AdminRole).Methods("GET")