Quiet counter (#574)

* only submit to influx when we log

* test accumulated value logging

src/counter.rs

@@ -6,9 +6,12 @@ use timing;
 
 pub struct Counter {
     pub name: &'static str,
+    /// total accumulated value
     pub counts: AtomicUsize,
     pub nanos: AtomicUsize,
     pub times: AtomicUsize,
+    /// last accumulated value logged
+    pub lastlog: AtomicUsize,
     pub lograte: usize,
 }
 
@@ -19,6 +22,7 @@ macro_rules! create_counter {
             counts: AtomicUsize::new(0),
             nanos: AtomicUsize::new(0),
             times: AtomicUsize::new(0),
+            lastlog: AtomicUsize::new(0),
             lograte: $lograte,
         }
     };
@@ -36,6 +40,7 @@ impl Counter {
         let counts = self.counts.fetch_add(events, Ordering::Relaxed);
         let nanos = self.nanos.fetch_add(total as usize, Ordering::Relaxed);
         let times = self.times.fetch_add(1, Ordering::Relaxed);
+        let lastlog = self.lastlog.load(Ordering::Relaxed);
         if times % self.lograte == 0 && times > 0 {
             info!(
                 "COUNTER:{{\"name\": \"{}\", \"counts\": {}, \"nanos\": {}, \"samples\": {}, \"rate\": {}, \"now\": {}}}",
@@ -46,16 +51,21 @@ impl Counter {
                 counts as f64 * 1e9 / nanos as f64,
                 timing::timestamp(),
             );
+            metrics::submit(
+                influxdb::Point::new(&format!("counter_{}", self.name))
+                    .add_field(
+                        "count",
+                        influxdb::Value::Integer(counts as i64 - lastlog as i64),
+                    )
+                    .add_field(
+                        "duration_ms",
+                        influxdb::Value::Integer(timing::duration_as_ms(&dur) as i64),
+                    )
+                    .to_owned(),
+            );
+            self.lastlog
+                .compare_and_swap(lastlog, counts, Ordering::Relaxed);
         }
-        metrics::submit(
-            influxdb::Point::new(&format!("counter_{}", self.name))
-                .add_field("count", influxdb::Value::Integer(events as i64))
-                .add_field(
-                    "duration_ms",
-                    influxdb::Value::Integer(timing::duration_as_ms(&dur) as i64),
-                )
-                .to_owned(),
-        );
     }
 }
 #[cfg(test)]
@@ -74,7 +84,18 @@ mod tests {
             assert_ne!(COUNTER.nanos.load(Ordering::Relaxed), 0);
             assert_eq!(COUNTER.times.load(Ordering::Relaxed), 1);
             assert_eq!(COUNTER.lograte, 100);
+            assert_eq!(COUNTER.lastlog.load(Ordering::Relaxed), 0);
             assert_eq!(COUNTER.name, "test");
         }
+        for _ in 0..199 {
+            inc_counter!(COUNTER, 2, start);
+        }
+        unsafe {
+            assert_eq!(COUNTER.lastlog.load(Ordering::Relaxed), 199);
+        }
+        inc_counter!(COUNTER, 2, start);
+        unsafe {
+            assert_eq!(COUNTER.lastlog.load(Ordering::Relaxed), 399);
+        }
     }
 }