From 8b432f8ca66acab27803a68c7d67388f93c8de34 Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Tue, 16 May 2017 19:10:55 -0700
Subject: [PATCH] funding: query fee estimator and scale to fee-per-kw when
 making chan

This commit modifies the funding workflow slightly to move the querying
to the fee estimator (for the new channel) into the fundingManager
rather than within the LightningWallet layer. When querying to
FeePerWeight, we now multiply by 1000 to arrive at fee-per-kw.

Additionally, we now also properly thread through the fee-per-kw
offered by the initiator the to the responder of the channel workflow.
---
 fundingmanager.go | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/fundingmanager.go b/fundingmanager.go
index 4ba1eb8a..daa7cd2c 100644
--- a/fundingmanager.go
+++ b/fundingmanager.go
@@ -540,7 +540,7 @@ func (f *fundingManager) handleFundingRequest(fmsg *fundingRequestMsg) {
 	reservation, err := f.cfg.Wallet.InitChannelReservation(amt, 0,
 		fmsg.peerAddress.IdentityKey, fmsg.peerAddress.Address,
 		uint16(fmsg.msg.ConfirmationDepth), delay, ourDustLimit,
-		msg.PushSatoshis)
+		msg.PushSatoshis, msg.FeePerKw)
 	if err != nil {
 		// TODO(roasbeef): push ErrorGeneric message
 		fndgLog.Errorf("Unable to initialize reservation: %v", err)
@@ -1250,12 +1250,23 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		msg.pushAmt, capacity, numConfs, msg.peerAddress.Address,
 		ourDustLimit)
 
+	// First, we'll query the fee estimator for a fee that should get the
+	// commitment transaction into the next block (conf target of 1). We
+	// target the next block here to ensure that we'll be able to execute a
+	// timely unilateral channel closure if needed.
+	// TODO(roasbeef): shouldn't be targeting next block
+	feePerWeight := btcutil.Amount(f.cfg.FeeEstimator.EstimateFeePerWeight(1))
+
+	// The protocol currently operates on the basis of fee-per-kw, so we'll
+	// multiply the computed sat/weight by 1000 to arrive at fee-per-kw.
+	feePerKw := feePerWeight * 1000
+
 	// Initialize a funding reservation with the local wallet. If the
 	// wallet doesn't have enough funds to commit to this channel, then
 	// the request will fail, and be aborted.
 	reservation, err := f.cfg.Wallet.InitChannelReservation(capacity,
 		localAmt, peerKey, msg.peerAddress.Address, uint16(numConfs), 4,
-		ourDustLimit, msg.pushAmt)
+		ourDustLimit, msg.pushAmt, feePerKw)
 	if err != nil {
 		msg.err <- err
 		return
@@ -1265,6 +1276,9 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 	// reservation throughout its lifetime.
 	chanID := f.nextPendingChanID()
 
+	fndgLog.Infof("Target sat/kw for pendingID(%x): %v", chanID,
+		int64(feePerKw))
+
 	// If a pending channel map for this peer isn't already created, then
 	// we create one, ultimately allowing us to track this pending
 	// reservation within the target peer.
@@ -1296,12 +1310,11 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		msg.peerAddress.Address, chanID)
 
 	// TODO(roasbeef): add FundingRequestFromContribution func
-	// TODO(roasbeef): need to set fee/kb
 	fundingReq := lnwire.NewSingleFundingRequest(
 		chanID,
 		msg.channelType,
 		msg.coinType,
-		0, // TODO(roasbeef): grab from fee estimation model
+		feePerKw,
 		capacity,
 		contribution.CsvDelay,
 		contribution.CommitKey,