autopilot+pilot: refactor connection logic out of OpenChannel

In this commit, we refactor the existing connection logic outside of the
ChanController's OpenChannel method. We do this as previously it was
possible for peers to stall us while attempting to connect to them. In
order to remedy this, we now attempt to connect the peer before tracking
them in our set of pending opens.

pilot.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"net"
 
@@ -24,60 +25,7 @@ type chanController struct {
 // specified amount. This function should un-block immediately after the
 // funding transaction that marks the channel open has been broadcast.
 func (c *chanController) OpenChannel(target *btcec.PublicKey,
-	amt btcutil.Amount, addrs []net.Addr) error {
-
-	// We can't establish a channel if no addresses were provided for the
-	// peer.
-	if len(addrs) == 0 {
-		return fmt.Errorf("Unable to create channel w/o an active " +
-			"address")
-	}
-
-	// First, we'll check if we're already connected to the target peer. If
-	// not, then we'll need to establish a connection.
-	if _, err := c.server.FindPeer(target); err != nil {
-		// TODO(roasbeef): try teach addr
-
-		atplLog.Tracef("Connecting to %x to auto-create channel: ",
-			target.SerializeCompressed())
-
-		lnAddr := &lnwire.NetAddress{
-			IdentityKey: target,
-			ChainNet:    activeNetParams.Net,
-		}
-
-		// We'll attempt to successively connect to each of the
-		// advertised IP addresses until we've either exhausted the
-		// advertised IP addresses, or have made a connection.
-		var connected bool
-		for _, addr := range addrs {
-			switch addr.(type) {
-			case *net.TCPAddr, *tor.OnionAddr:
-				lnAddr.Address = addr
-			default:
-				return fmt.Errorf("unknown address type %T", addr)
-			}
-
-			// TODO(roasbeef): make perm connection in server after
-			// chan open?
-			err := c.server.ConnectToPeer(lnAddr, false)
-			if err != nil {
-				// If we weren't able to connect to the peer,
-				// then we'll move onto the next.
-				continue
-			}
-
-			connected = true
-			break
-		}
-
-		// If we weren't able to establish a connection at all, then
-		// we'll error out.
-		if !connected {
-			return fmt.Errorf("Unable to connect to %x",
-				target.SerializeCompressed())
-		}
-	}
+	amt btcutil.Amount) error {
 
 	// With the connection established, we'll now establish our connection
 	// to the target peer, waiting for the first update before we exit.
@@ -160,6 +108,64 @@ func initAutoPilot(svr *server, cfg *autoPilotConfig) (*autopilot.Agent, error)
 		},
 		Graph:           autopilot.ChannelGraphFromDatabase(svr.chanDB.ChannelGraph()),
 		MaxPendingOpens: 10,
+		ConnectToPeer: func(target *btcec.PublicKey, addrs []net.Addr) (bool, error) {
+			// We can't establish a channel if no addresses were
+			// provided for the peer.
+			if len(addrs) == 0 {
+				return false, errors.New("no addresses specified")
+			}
+
+			// First, we'll check if we're already connected to the
+			// target peer. If we are, we can exit early. Otherwise,
+			// we'll need to establish a connection.
+			if _, err := svr.FindPeer(target); err == nil {
+				return true, nil
+			}
+
+			atplLog.Tracef("Attempting to connect to %x",
+				target.SerializeCompressed())
+
+			lnAddr := &lnwire.NetAddress{
+				IdentityKey: target,
+				ChainNet:    activeNetParams.Net,
+			}
+
+			// We'll attempt to successively connect to each of the
+			// advertised IP addresses until we've either exhausted
+			// the advertised IP addresses, or have made a
+			// connection.
+			var connected bool
+			for _, addr := range addrs {
+				switch addr.(type) {
+				case *net.TCPAddr, *tor.OnionAddr:
+					lnAddr.Address = addr
+				default:
+					return false, fmt.Errorf("unknown "+
+						"address type %T", addr)
+				}
+
+				err := svr.ConnectToPeer(lnAddr, false)
+				if err != nil {
+					// If we weren't able to connect to the
+					// peer at this address, then we'll move
+					// onto the next.
+					continue
+				}
+
+				connected = true
+				break
+			}
+
+			// If we weren't able to establish a connection at all,
+			// then we'll error out.
+			if !connected {
+				return false, fmt.Errorf("unable to connect "+
+					"to %x", target.SerializeCompressed())
+			}
+
+			return false, nil
+		},
+		DisconnectPeer: svr.DisconnectPeer,
 	}
 
 	// Next, we'll fetch the current state of open channels from the