Add allow unbalance options

README.md

@@ -51,6 +51,8 @@ rebalance-lnd](https://github.com/accumulator/rebalance-lnd).
   -r, --econ-ratio=          economical ratio for fee limit calculation as a multiple of target channel fee (for
                              example, 0.5 means you want to pay at max half the fee you might earn for routing out of
                              the target channel)
+  -F, --fee-limit-ppm=       don't consider the target channel fee and use this max fee ppm instead
+                             (can rebalance at a loss, be careful)
   -l, --lost-profit          also consider the outbound channel fees when looking for profitable routes so that
                              outbound_fee+inbound_fee < route_fee
   -b, --probe=               if the payment fails at the last hop try to probe lower amount using this many steps
@@ -61,6 +63,10 @@ rebalance-lnd](https://github.com/accumulator/rebalance-lnd).
   -d, --exclude-node=        don't use this node for routing (can be specified multiple times)
       --to=                  try only this channel as target (should satisfy other constraints too)
       --from=                try only this channel as source (should satisfy other constraints too)
+      --allow-unbalance-from let the source channel go below 50% local liquidity, use if you want to drain a channel;
+                             you should also set --pfrom to >50
+      --allow-unbalance-to   let the target channel go above 50% local liquidity, use if you want to refill a channel;
+                             you should also set --pto to >50
   -s, --stat=                save successful rebalance information to the specified CSV file
 ```
 

channels.go

@@ -40,7 +40,8 @@ func (r *regolancer) getChannelCandidates(fromPerc, toPerc, amount int64) error
 		if _, ok := r.excludeBoth[c.ChanId]; ok {
 			continue
 		}
-		if c.LocalBalance < c.Capacity*toPerc/100 && c.LocalBalance+amount < c.Capacity/2 {
+		if c.LocalBalance < c.Capacity*toPerc/100 && (params.AllowUnbalanceTo ||
+			c.LocalBalance+amount < c.Capacity/2) {
 			if _, ok := r.excludeIn[c.ChanId]; ok {
 				continue
 			}
@@ -48,7 +49,9 @@ func (r *regolancer) getChannelCandidates(fromPerc, toPerc, amount int64) error
 				r.toChannels = append(r.toChannels, c)
 			}
 		}
-		if c.RemoteBalance < c.Capacity*fromPerc/100 && c.RemoteBalance+amount < c.Capacity/2 {
+		if c.RemoteBalance < c.Capacity*fromPerc/100 &&
+			(params.AllowUnbalanceFrom ||
+				c.RemoteBalance+amount < c.Capacity/2) {
 			if _, ok := r.excludeOut[c.ChanId]; ok {
 				continue
 			}
@@ -101,7 +104,13 @@ func (r *regolancer) pickChannelPair(amount, minAmount int64) (from uint64, to u
 	fromChan = pair[0]
 	toChan = pair[1]
 	maxFrom := fromChan.Capacity/2 - fromChan.RemoteBalance
+	if params.AllowUnbalanceFrom {
+		maxFrom = fromChan.LocalBalance
+	}
 	maxTo := toChan.Capacity/2 - toChan.LocalBalance
+	if params.AllowUnbalanceTo {
+		maxTo = toChan.RemoteBalance
+	}
 	if amount == 0 {
 		maxAmount = min(maxFrom, maxTo)
 	} else {

main.go

@@ -42,6 +42,8 @@ var params struct {
 	ExcludeNodes       []string `short:"d" long:"exclude-node" description:"don't use this node for routing (can be specified multiple times)" json:"exclude_nodes" toml:"exclude_nodes"`
 	ToChannel          uint64   `long:"to" description:"try only this channel as target (should satisfy other constraints too)" json:"to" toml:"to"`
 	FromChannel        uint64   `long:"from" description:"try only this channel as source (should satisfy other constraints too)" json:"from" toml:"from"`
+	AllowUnbalanceFrom bool     `long:"allow-unbalance-from" description:"let the source channel go below 50% local liquidity, use if you want to drain a channel; you should also set --pfrom to >50" json:"allow_unbalance_from" toml:"allow_unbalance_from"`
+	AllowUnbalanceTo   bool     `long:"allow-unbalance-to" description:"let the target channel go above 50% local liquidity, use if you want to refill a channel; you should also set --pto to >50" json:"allow_unbalance_to" toml:"allow_unbalance_to"`
 	StatFilename       string   `short:"s" long:"stat" description:"save successful rebalance information to the specified CSV file" json:"stat" toml:"stat"`
 }