fix: add block number value to the metrics

crates/chain-listener/src/listener.rs

@@ -647,7 +647,7 @@ impl ChainListener {
         let header = event.ok_or(eyre!("Failed to process newHeads event: got None"))?;
 
         let (block_timestamp, block_number) = Self::parse_block_header(header?)?;
-        self.observe(|m| m.observe_new_block(block_number.to_string()));
+        self.observe(|m| m.observe_new_block(block_number));
 
         // `epoch_number = 1 + (block_timestamp - init_timestamp) / epoch_duration`
         let epoch_number =
@@ -684,7 +684,7 @@ impl ChainListener {
                 }
             }
         }
-        self.observe(|m| m.observe_processed_block());
+        self.observe(|m| m.observe_processed_block(block_number));
         Ok(())
     }
 
@@ -1117,7 +1117,7 @@ impl ChainListener {
         }
     }
 
-    fn parse_block_header(header: Value) -> eyre::Result<(U256, U256)> {
+    fn parse_block_header(header: Value) -> eyre::Result<(U256, i64)> {
         let obj = header.as_object().ok_or(eyre::eyre!(
             "newHeads: header is not an object; got {header}"
         ))?;
@@ -1138,7 +1138,13 @@ impl ChainListener {
             ))?
             .to_string();
 
-        Ok((U256::from_str(&timestamp)?, U256::from_str(&block_number)?))
+        let block_number = U256::from_str(&block_number)?;
+        // take lower bits from the number (they are in the order 'least significant first')
+        // we're okay with ignoring higher bits since they 1) probably, won't be reached in practice
+        // 2) don't help alerts very much, lower bits are enough
+        let block_number = block_number.as_limbs()[0] as i64;
+
+        Ok((U256::from_str(&timestamp)?, block_number))
     }
 
     async fn poll_deal_statuses(&mut self) -> eyre::Result<()> {

crates/peer-metrics/src/chain_listener.rs

@@ -2,14 +2,10 @@ use crate::{execution_time_buckets, register};
 use prometheus_client::encoding::EncodeLabelSet;
 use prometheus_client::metrics::counter::Counter;
 use prometheus_client::metrics::exemplar::CounterWithExemplar;
+use prometheus_client::metrics::gauge::Gauge;
 use prometheus_client::metrics::histogram::Histogram;
 use prometheus_client::registry::Registry;
 
-#[derive(EncodeLabelSet, Hash, Clone, Eq, PartialEq, Debug)]
-struct BlockLabel {
-    block_number: String,
-}
-
 #[derive(EncodeLabelSet, Hash, Clone, Eq, PartialEq, Debug)]
 struct TxLabel {
     tx_hash: String,
@@ -33,9 +29,11 @@ pub struct ChainListenerMetrics {
     // how many proofs transaction are failed
     ccp_proofs_tx_failed: CounterWithExemplar<TxLabel>,
     // How many blocks we have received from the newHead subscription
-    blocks_seen: CounterWithExemplar<BlockLabel>,
+    blocks_seen: Counter,
+    last_seen_block: Gauge,
     // How many block we manage to process while processing the block
     blocks_processed: Counter,
+    last_process_block: Gauge,
 }
 
 impl ChainListenerMetrics {
@@ -93,7 +91,7 @@ impl ChainListenerMetrics {
 
         let blocks_seen = register(
             sub_registry,
-            CounterWithExemplar::default(),
+            Counter::default(),
             "blocks_seen",
             "Total number of blocks seen from the newHead subscription",
         );
@@ -105,6 +103,19 @@ impl ChainListenerMetrics {
             "Total number of blocks processed",
         );
 
+        let last_seen_block = register(
+            sub_registry,
+            Gauge::default(),
+            "last_seen_block",
+            "Last block seen from the newHead subscription",
+        );
+        let last_process_block = register(
+            sub_registry,
+            Gauge::default(),
+            "last_process_block",
+            "Last processed block from the newHead subscription",
+        );
+
         Self {
             ccp_requests_total,
             ccp_replies_total,
@@ -114,7 +125,9 @@ impl ChainListenerMetrics {
             ccp_proofs_tx_success,
             ccp_proofs_tx_failed,
             blocks_seen,
+            last_seen_block,
             blocks_processed,
+            last_process_block,
         }
     }
 
@@ -144,12 +157,13 @@ impl ChainListenerMetrics {
             .inc_by(1, Some(TxLabel { tx_hash }));
     }
 
-    pub fn observe_new_block(&self, block_number: String) {
-        self.blocks_seen
-            .inc_by(1, Some(BlockLabel { block_number }));
+    pub fn observe_new_block(&self, block_number: i64) {
+        self.blocks_seen.inc();
+        self.last_seen_block.set(block_number);
     }
 
-    pub fn observe_processed_block(&self) {
+    pub fn observe_processed_block(&self, block_number: i64) {
         self.blocks_processed.inc();
+        self.last_process_block.set(block_number);
     }
 }