Provide a utility to log the ProbabilisticScorer's contents

I wrote this when debugging a user's scorer and figured it may be
useful upstream.

diff --git a/lightning/src/routing/scoring.rs b/lightning/src/routing/scoring.rs
index 0e04c63903392b8ccfc36d72c3fa87109b86c17b..3d10a14c6f2cf7c7d63403ef07f70f8c05ee2e59 100644 (file)
--- a/lightning/src/routing/scoring.rs
+++ b/lightning/src/routing/scoring.rs
@@ -623,6 +623,33 @@ impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> ProbabilisticScorerUsin
                assert!(self.channel_liquidities.insert(short_channel_id, liquidity).is_none());
                self
        }
+
+       /// Dump the contents of this scorer into the configured logger.
+       ///
+       /// Note that this writes roughly one line per channel for which we have a liquidity estimate,
+       /// which may be a substantial amount of log output.
+       pub fn debug_log_liquidity_stats(&self) {
+               let graph = self.network_graph.read_only();
+               for (scid, liq) in self.channel_liquidities.iter() {
+                       if let Some(chan_debug) = graph.channels().get(scid) {
+                               let log_direction = |source, target| {
+                                       if let Some((directed_info, _)) = chan_debug.as_directed_to(target) {
+                                               let amt = directed_info.effective_capacity().as_msat();
+                                               let dir_liq = liq.as_directed(source, target, amt, self.params.liquidity_offset_half_life);
+                                               log_debug!(self.logger, "Liquidity from {:?} to {:?} via {} is in the range ({}, {})",
+                                                       source, target, scid, dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat());
+                                       } else {
+                                               log_debug!(self.logger, "No amount known for SCID {} from {:?} to {:?}", scid, source, target);
+                                       }
+                               };
+
+                               log_direction(&chan_debug.node_one, &chan_debug.node_two);
+                               log_direction(&chan_debug.node_two, &chan_debug.node_one);
+                       } else {
+                               log_debug!(self.logger, "No network graph entry for SCID {}", scid);
+                       }
+               }
+       }
 }
 
 impl ProbabilisticScoringParameters {