Return actual mempool fee histogram from RPC

Also, add this to the CLI tracker tool and improve logging.

src/bin/tracker.rs

@@ -5,7 +5,7 @@ extern crate log;
 
 use indexrs::{daemon, mempool};
 use std::thread;
-use std::time::{Duration, Instant};
+use std::time::Duration;
 
 fn main() {
     use simplelog::*;
@@ -18,14 +18,23 @@ fn main() {
     let daemon = daemon::Daemon::new("localhost:8332");
     let mut tracker = mempool::Tracker::new();
     loop {
-        let t = Instant::now();
         tracker.update(&daemon).unwrap();
-        let dt = t.elapsed();
+        let h = tracker.fee_histogram();
+        let mut total_vsize = 0;
+        let mut limit = 0;
+        for (fee, vsize) in h {
+            total_vsize += vsize;
+            let new_limit = total_vsize as usize / 1_000_000;
+            if limit != new_limit {
+                limit = new_limit;
                 info!(
-            "update took {:.3} ms",
-            (dt.as_secs() as f64 + 1e-9f64 * dt.subsec_nanos() as f64) * 1e3
+                    "{:.2}MB has fee >= {:.1} sat/vbyte",
+                    total_vsize as f32 / 1e6,
+                    fee
                 );
-        info!("histogram: {:?}", tracker.fee_histogram());
-        thread::sleep(Duration::from_secs(1));
+            }
+        }
+        info!("{:.2}MB total size", total_vsize as f32 / 1e6);
+        thread::sleep(Duration::from_secs(10));
     }
 }

src/mempool.rs

@@ -1,8 +1,10 @@
 use bitcoin::blockdata::transaction::Transaction;
 use bitcoin::util::hash::Sha256dHash;
 use daemon::{Daemon, MempoolEntry};
+
 use std::collections::{HashMap, HashSet};
 use std::iter::FromIterator;
+use std::time::{Duration, Instant};
 
 error_chain!{}
 
@@ -23,6 +25,16 @@ pub struct Tracker {
     stats: HashMap<Sha256dHash, Stats>,
 }
 
+trait InSeconds {
+    fn in_seconds(&self) -> f64;
+}
+
+impl InSeconds for Duration {
+    fn in_seconds(&self) -> f64 {
+        self.as_secs() as f64 + (self.subsec_nanos() as f64) * 1e-9f64
+    }
+}
+
 impl Tracker {
     pub fn new() -> Tracker {
         Tracker {
@@ -56,31 +68,36 @@ impl Tracker {
             .getmempooltxids()
             .chain_err(|| "failed to update mempool from daemon")?);
         let old_txids = HashSet::from_iter(self.stats.keys().cloned());
-
-        let mut to_add = Vec::new();
+        let t = Instant::now();
         for &txid in new_txids.difference(&old_txids) {
-            let tx = match daemon.gettransaction(&txid) {
-                Ok(tx) => tx,
-                Err(err) => {
-                    warn!("missing tx {}: {}", txid, err);
-                    continue;
-                }
-            };
             let entry = match daemon.getmempoolentry(&txid) {
                 Ok(entry) => entry,
                 Err(err) => {
+                    // e.g. new block or RBF
                     warn!("no mempool entry {}: {}", txid, err);
                     continue;
                 }
             };
-            trace!("new tx: {}, {:.3}", txid, entry.fee_per_vbyte(),);
-            to_add.push((txid, Stats::new(tx, entry)));
+            let tx = match daemon.gettransaction(&txid) {
+                Ok(tx) => tx,
+                Err(err) => {
+                    // e.g. new block or RBF
+                    warn!("missing tx {}: {}", txid, err);
+                    continue;
+                }
+            };
+            trace!("new tx: {}, {:.3}", txid, entry.fee_per_vbyte(),);
+            self.stats.insert(txid, Stats::new(tx, entry));
         }
-        self.stats.extend(to_add);
         for txid in old_txids.difference(&new_txids) {
             self.stats.remove(txid);
         }
-        assert_eq!(new_txids, HashSet::from_iter(self.stats.keys().cloned()));
+        let dt = t.elapsed();
+        debug!(
+            "mempool update took {:.1} ms ({} txns)",
+            dt.in_seconds() * 1e3,
+            self.stats.len()
+        );
         Ok(())
     }
 }

src/query.rs

@@ -216,4 +216,8 @@ impl<'a> Query<'a> {
             .update(self.daemon)
             .chain_err(|| "failed to update mempool")
     }
+
+    pub fn get_fee_histogram(&self) -> Vec<(f32, u32)> {
+        self.tracker.read().unwrap().fee_histogram()
+    }
 }

src/rpc.rs

@@ -107,7 +107,7 @@ impl<'a> Handler<'a> {
     }
 
     fn mempool_get_fee_histogram(&self) -> Result<Value> {
-        Ok(json!([])) // TODO: consult with actual mempool
+        Ok(json!(self.query.get_fee_histogram()))
     }
 
     fn blockchain_block_get_chunk(&self, params: &[Value]) -> Result<Value> {