package client import ( "context" "errors" "fmt" "sync" "time" "github.com/tendermint/tendermint/libs/log" "github.com/tendermint/tendermint/types" ) // Waiter is informed of current height, decided whether to quit early type Waiter func(delta int64) (abort error) // DefaultWaitStrategy is the standard backoff algorithm, // but you can plug in another one func DefaultWaitStrategy(delta int64) (abort error) { if delta > 10 { return fmt.Errorf("waiting for %d blocks... aborting", delta) } else if delta > 0 { // estimate of wait time.... // wait half a second for the next block (in progress) // plus one second for every full block delay := time.Duration(delta-1)*time.Second + 500*time.Millisecond time.Sleep(delay) } return nil } // Wait for height will poll status at reasonable intervals until // the block at the given height is available. // // If waiter is nil, we use DefaultWaitStrategy, but you can also // provide your own implementation func WaitForHeight(ctx context.Context, c StatusClient, h int64, waiter Waiter) error { if waiter == nil { waiter = DefaultWaitStrategy } delta := int64(1) for delta > 0 { s, err := c.Status(ctx) if err != nil { return err } delta = h - s.SyncInfo.LatestBlockHeight // wait for the time, or abort early if err := waiter(delta); err != nil { return err } } return nil } // WaitForOneEvent subscribes to a websocket event for the given // event time and returns upon receiving it one time, or // when the timeout duration has expired. // // This handles subscribing and unsubscribing under the hood func WaitForOneEvent(c EventsClient, eventValue string, timeout time.Duration) (types.EventData, error) { const subscriber = "helpers" ctx, cancel := context.WithTimeout(context.Background(), timeout) defer cancel() // register for the next event of this type eventCh, err := c.Subscribe(ctx, subscriber, types.QueryForEvent(eventValue).String()) if err != nil { return nil, fmt.Errorf("failed to subscribe: %w", err) } // make sure to un-register after the test is over defer func() { if deferErr := c.UnsubscribeAll(ctx, subscriber); deferErr != nil { panic(err) } }() select { case event := <-eventCh: return event.Data, nil case <-ctx.Done(): return nil, errors.New("timed out waiting for event") } } var ( // ErrClientRunning is returned by Start when the client is already running. ErrClientRunning = errors.New("client already running") // ErrClientNotRunning is returned by Stop when the client is not running. ErrClientNotRunning = errors.New("client is not running") ) // RunState is a helper that a client implementation can embed to implement // common plumbing for keeping track of run state and logging. // // TODO(creachadair): This type is a temporary measure, and will be removed. // See the discussion on #6971. type RunState struct { Logger log.Logger mu sync.Mutex name string isRunning bool } // NewRunState returns a new unstarted run state tracker with the given logging // label and log sink. If logger == nil, a no-op logger is provided by default. func NewRunState(name string, logger log.Logger) *RunState { if logger == nil { logger = log.NewNopLogger() } return &RunState{ name: name, Logger: logger, } } // Start sets the state to running, or reports an error. func (r *RunState) Start(context.Context) error { r.mu.Lock() defer r.mu.Unlock() if r.isRunning { r.Logger.Error("not starting client, it is already started", "client", r.name) return ErrClientRunning } r.Logger.Info("starting client", "client", r.name) r.isRunning = true return nil } // Stop sets the state to not running, or reports an error. func (r *RunState) Stop() error { r.mu.Lock() defer r.mu.Unlock() if !r.isRunning { r.Logger.Error("not stopping client; it is already stopped", "client", r.name) return ErrClientNotRunning } r.Logger.Info("stopping client", "client", r.name) r.isRunning = false return nil } // IsRunning reports whether the state is running. func (r *RunState) IsRunning() bool { r.mu.Lock() defer r.mu.Unlock() return r.isRunning }