Discovery metrics (#1276)

* Silky smooth squash

* Add discovery metrics

* Fix gauge metric, increase discv5 sessions

* Formatting

beacon_node/eth2_libp2p/src/metrics.rs

@@ -21,8 +21,39 @@ lazy_static! {
         "discovery_queue_size",
         "The number of discovery queries awaiting execution"
     );
-    pub static ref DISCOVERY_REQS: Result<IntGauge> = try_create_int_gauge(
+    pub static ref DISCOVERY_REQS: Result<Gauge> = try_create_float_gauge(
         "discovery_requests",
         "The number of unsolicited discovery requests per second"
     );
+    pub static ref DISCOVERY_SESSIONS: Result<IntGauge> = try_create_int_gauge(
+        "discovery_sessions",
+        "The number of active discovery sessions with peers"
+    );
+    pub static ref DISCOVERY_REQS_IP: Result<GaugeVec> = try_create_float_gauge_vec(
+        "discovery_reqs_per_ip",
+        "Unsolicited discovery requests per ip per second",
+        &["Addresses"]
+    );
+}
+
+pub fn scrape_discovery_metrics() {
+    let metrics = discv5::metrics::Metrics::from(discv5::Discv5::raw_metrics());
+
+    set_float_gauge(&DISCOVERY_REQS, metrics.unsolicited_requests_per_second);
+
+    set_gauge(&DISCOVERY_SESSIONS, metrics.active_sessions as i64);
+
+    let process_gauge_vec = |gauge: &Result<GaugeVec>, metrics: discv5::metrics::Metrics| {
+        if let Ok(gauge_vec) = gauge {
+            gauge_vec.reset();
+            for (ip, value) in metrics.requests_per_ip_per_second.iter() {
+                if let Ok(metric) = gauge_vec.get_metric_with_label_values(&[&format!("{:?}", ip)])
+                {
+                    metric.set(*value);
+                }
+            }
+        }
+    };
+
+    process_gauge_vec(&DISCOVERY_REQS_IP, metrics);
 }