chore: adding batch size metric

Signed-off-by: Simon Paitrault <[email protected]>

crates/topos-metrics/src/lib.rs

@@ -1,4 +1,4 @@
-use prometheus::{self, register_int_gauge, IntCounter, IntGauge};
+use prometheus::{self, register_histogram, register_int_gauge, Histogram, IntCounter, IntGauge};
 
 use lazy_static::lazy_static;
 use prometheus::register_int_counter;
@@ -22,6 +22,12 @@ lazy_static! {
         "Number of gossipsub message sent."
     )
     .unwrap();
+    pub static ref P2P_GOSSIP_BATCH_SIZE: Histogram = register_histogram!(
+        "p2p_gossip_batch_size",
+        "Number of message sent in a gossip batch.",
+        vec![1.0, 2.0, 3.0, 4.0, 5.0, 10.0, 20.0]
+    ).unwrap();
+
 
     // Double echo
     pub static ref DOUBLE_ECHO_BUFFER_CAPACITY: IntCounter = register_int_counter!(

crates/topos-p2p/src/behaviour/gossip.rs

@@ -7,6 +7,7 @@ use libp2p::{
     swarm::{NetworkBehaviour, THandlerInEvent, ToSwarm},
 };
 use serde::{Deserialize, Serialize};
+use topos_metrics::P2P_GOSSIP_BATCH_SIZE;
 
 use crate::{event::ComposedEvent, TOPOS_ECHO, TOPOS_GOSSIP, TOPOS_READY};
 
@@ -149,6 +150,7 @@ impl NetworkBehaviour for Behaviour {
                     }
                 }
 
+                P2P_GOSSIP_BATCH_SIZE.observe(echos.data.len() as f64);
                 let msg = bincode::serialize::<Batch>(&echos).expect("msg ser");
 
                 _ = self.gossipsub.publish(IdentTopic::new(TOPOS_ECHO), msg);
@@ -164,6 +166,7 @@ impl NetworkBehaviour for Behaviour {
                     }
                 }
 
+                P2P_GOSSIP_BATCH_SIZE.observe(readies.data.len() as f64);
                 let msg = bincode::serialize::<Batch>(&readies).expect("msg ser");
 
                 _ = self.gossipsub.publish(IdentTopic::new(TOPOS_READY), msg);