netann: add RequestAuto for restoring auto chan state management

If a channel was manually disabled, subsequent automatic / background
requests to update that channel's state will be ignored. A RequestAuto
call restores automatic / background state management and indicates
that such requests should no longer be ignored.

netann/chan_status_manager.go

@@ -111,6 +111,10 @@ type ChanStatusManager struct {
 	// primary event loop.
 	disableRequests chan statusRequest
 
+	// autoRequests pipes external requests to restore automatic channel
+	// state management into the primary event loop.
+	autoRequests chan statusRequest
+
 	// statusSampleTicker fires at the interval prescribed by
 	// ChanStatusSampleInterval to check if channels in chanStates have
 	// become inactive.
@@ -154,6 +158,7 @@ func NewChanStatusManager(cfg *ChanStatusConfig) (*ChanStatusManager, error) {
 		statusSampleTicker: time.NewTicker(cfg.ChanStatusSampleInterval),
 		enableRequests:     make(chan statusRequest),
 		disableRequests:    make(chan statusRequest),
+		autoRequests:       make(chan statusRequest),
 		quit:               make(chan struct{}),
 	}, nil
 }
@@ -263,6 +268,13 @@ func (m *ChanStatusManager) RequestDisable(outpoint wire.OutPoint,
 	return m.submitRequest(m.disableRequests, outpoint, manual)
 }
 
+// RequestAuto submits a request to restore automatic channel state management.
+// If the channel is in the state ChanStatusManuallyDisabled, it will be moved
+// back to the state ChanStatusDisabled. Otherwise, no action will be taken.
+func (m *ChanStatusManager) RequestAuto(outpoint wire.OutPoint) error {
+	return m.submitRequest(m.autoRequests, outpoint, true)
+}
+
 // statusRequest is passed to the statusManager to request a change in status
 // for a particular channel point.  The exact action is governed by passing the
 // request through one of the enableRequests or disableRequests channels.
@@ -321,6 +333,10 @@ func (m *ChanStatusManager) statusManager() {
 		case req := <-m.disableRequests:
 			req.errChan <- m.processDisableRequest(req.outpoint, req.manual)
 
+		// Process any requests to restore automatic channel state management.
+		case req := <-m.autoRequests:
+			req.errChan <- m.processAutoRequest(req.outpoint)
+
 		// Use long-polling to detect when channels become inactive.
 		case <-m.statusSampleTicker.C:
 			// First, do a sweep and mark any ChanStatusEnabled
@@ -444,6 +460,27 @@ func (m *ChanStatusManager) processDisableRequest(outpoint wire.OutPoint,
 	return nil
 }
 
+// processAutoRequest attempts to restore automatic channel state management
+// for the given outpoint. If the method returns nil, the state of the channel
+// will no longer be ChanStatusManuallyDisabled (currently the only state in
+// which automatic / background requests are ignored).
+//
+// No update will be sent on the network.
+func (m *ChanStatusManager) processAutoRequest(outpoint wire.OutPoint) error {
+	curState, err := m.getOrInitChanStatus(outpoint)
+	if err != nil {
+		return err
+	}
+
+	if curState.Status == ChanStatusManuallyDisabled {
+		log.Debugf("Restoring automatic control for manually disabled "+
+			"channel(%v)", outpoint)
+
+		m.chanStates.markDisabled(outpoint)
+	}
+	return nil
+}
+
 // markPendingInactiveChannels performs a sweep of the database's active
 // channels and determines which, if any, should have a disable announcement
 // scheduled. Once an active channel is determined to be pending-inactive, one