rpcserver: allow channels to be opened using --node_id

This commit fixes a slight bug in the interaction between the cli
program and the rpcsever itself. With this commit it’s now again
possible to create a channel with a peer that’s identified by its
peerID, instead of only the pubkey.

rpcserver.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"math"
 	"net"
+	"strings"
 	"time"
 
 	"sync"
@@ -244,10 +245,19 @@ func (r *rpcServer) OpenChannel(in *lnrpc.OpenChannelRequest,
 			"state must be below the local funding amount")
 	}
 
-	// TODO(roasbeef): make it optional
-	nodepubKey, err := btcec.ParsePubKey(in.NodePubkey, btcec.S256())
-	if err != nil {
-		return err
+	var (
+		nodepubKey *btcec.PublicKey
+		err        error
+	)
+
+	// If the node key is set, the we'll parse the raw bytes into a pubkey
+	// object so we can easily manipulate it. If this isn't set, then we
+	// expected the TargetPeerId to be set accordingly.
+	if len(in.NodePubkey) != 0 {
+		nodepubKey, err = btcec.ParsePubKey(in.NodePubkey, btcec.S256())
+		if err != nil {
+			return err
+		}
 	}
 
 	// Instruct the server to trigger the necessary events to attempt to

server.go

@@ -713,9 +713,17 @@ func (s *server) handleConnectPeer(msg *connectPeerMsg) {
 // request to the funding manager allowing it to initiate the channel funding
 // workflow.
 func (s *server) handleOpenChanReq(req *openChanReq) {
-	var targetPeer *peer
+	var (
+		targetPeer *peer
+		pubStr     string
+	)
 
-	pubStr := string(req.targetPubkey.SerializeCompressed())
+	// If the user is targeting the peer by public key, then we'll need to
+	// convert that into a string for our map. Otherwise, we expect them to
+	// target by peer ID instead.
+	if req.targetPubkey != nil {
+		pubStr = string(req.targetPubkey.SerializeCompressed())
+	}
 
 	// First attempt to locate the target peer to open a channel with, if
 	// we're unable to locate the peer then this request will fail.