package imap import ( "fmt" "math" "sync" "time" "git.sr.ht/~rjarry/aerc/worker/types" "github.com/emersion/go-imap" ) // observer monitors the loggedOut channel of the imap client. If the logout // signal is received, the observer will emit a connection error to the ui in // order to start the reconnect cycle. type observer struct { sync.Mutex config imapConfig client *imapClient worker *types.Worker done chan struct{} autoReconnect bool retries int running bool } func newObserver(cfg imapConfig, w *types.Worker) *observer { return &observer{config: cfg, worker: w, done: make(chan struct{})} } func (o *observer) SetClient(c *imapClient) { o.Stop() o.Lock() o.client = c o.Unlock() o.Start() o.retries = 0 } func (o *observer) SetAutoReconnect(auto bool) { o.autoReconnect = auto } func (o *observer) AutoReconnect() bool { return o.autoReconnect } func (o *observer) isClientConnected() bool { o.Lock() defer o.Unlock() return o.client != nil && o.client.State() == imap.SelectedState } func (o *observer) EmitIfNotConnected() bool { if !o.isClientConnected() { o.emit("imap client not connected: attempt reconnect") return true } return false } func (o *observer) IsRunning() bool { return o.running } func (o *observer) Start() { if o.running { o.log("runs already") return } if o.client == nil { return } if o.EmitIfNotConnected() { return } go func() { select { case <-o.client.LoggedOut(): o.log("<-logout") if o.autoReconnect { o.emit("logged out") } else { o.log("ignore logout (auto-reconnect off)") } case <-o.done: o.log("<-done") } o.running = false o.log("stopped") }() o.running = true o.log("started") } func (o *observer) Stop() { if o.client == nil { return } if o.done != nil { close(o.done) } o.done = make(chan struct{}) o.running = false } func (o *observer) DelayedReconnect() error { if o.client == nil { return nil } var wait time.Duration var reterr error if o.retries > 0 { backoff := int(math.Pow(1.8, float64(o.retries))) var err error wait, err = time.ParseDuration(fmt.Sprintf("%ds", backoff)) if err != nil { return err } if wait > o.config.reconnect_maxwait { wait = o.config.reconnect_maxwait } reterr = fmt.Errorf("reconnect in %v", wait) } else { reterr = fmt.Errorf("reconnect") } go func() { <-time.After(wait) o.emit(reterr.Error()) }() o.retries++ return reterr } func (o *observer) emit(errMsg string) { o.log("disconnect done->") o.worker.PostMessage(&types.Done{ Message: types.RespondTo(&types.Disconnect{})}, nil) o.log("connection error->") o.worker.PostMessage(&types.ConnError{ Error: fmt.Errorf(errMsg), }, nil) } func (o *observer) log(args ...interface{}) { header := fmt.Sprintf("observer (%p) [running:%t]", o, o.running) o.worker.Logger.Println(append([]interface{}{header}, args...)...) }