autopilot: add OnChannelPendingOpen state update

autopilot/agent.go

@@ -186,13 +186,18 @@ type balanceUpdate struct {
 	balanceDelta btcutil.Amount
 }
 
-// chanOpenUpdate is a type of external state update the indicates a new
+// chanOpenUpdate is a type of external state update that indicates a new
 // channel has been opened, either by the Agent itself (within the main
 // controller loop), or by an external user to the system.
 type chanOpenUpdate struct {
 	newChan Channel
 }
 
+// chanPendingOpenUpdate is a type of external state update that indicates a new
+// channel has been opened, either by the agent itself or an external subsystem,
+// but is still pending.
+type chanPendingOpenUpdate struct{}
+
 // chanOpenFailureUpdate is a type of external state update that indicates
 // a previous channel open failed, and that it might be possible to try again.
 type chanOpenFailureUpdate struct{}
@@ -231,6 +236,18 @@ func (a *Agent) OnChannelOpen(c Channel) {
 	}()
 }
 
+// OnChannelPendingOpen is a callback that should be executed each time a new
+// channel is opened, either by the agent or an external subsystems, but is
+// still pending.
+func (a *Agent) OnChannelPendingOpen() {
+	go func() {
+		select {
+		case a.stateUpdates <- &chanPendingOpenUpdate{}:
+		case <-a.quit:
+		}
+	}()
+}
+
 // OnChannelOpenFailure is a callback that should be executed when the
 // autopilot has attempted to open a channel, but failed. In this case we can
 // retry channel creation with a different node.
@@ -382,6 +399,12 @@ func (a *Agent) controller(startingBalance btcutil.Amount) {
 
 				updateBalance()
 
+			// A new channel has been opened by the agent or an
+			// external subsystem, but is still pending
+			// confirmation.
+			case *chanPendingOpenUpdate:
+				updateBalance()
+
 			// A channel has been closed, this may free up an
 			// available slot, triggering a new channel update.
 			case *chanCloseUpdate:
@@ -598,6 +621,12 @@ func (a *Agent) controller(startingBalance btcutil.Amount) {
 								err)
 						}
 					}
+
+					// Since the channel open was successful
+					// and is currently pending, we'll
+					// trigger the autopilot agent to query
+					// for more peers.
+					a.OnChannelPendingOpen()
 				}(chanCandidate)
 			}
 			pendingMtx.Unlock()