Additional light client metrics (#6545)

* Fix db query and add some additional metrics

* fmt

* Update beacon_node/beacon_chain/src/metrics.rs

Co-authored-by: Jimmy Chen <jchen.tc@gmail.com>

* Update beacon_node/beacon_chain/src/metrics.rs

Co-authored-by: Jimmy Chen <jchen.tc@gmail.com>

beacon_node/beacon_chain/src/light_client_server_cache.rs

@@ -85,6 +85,7 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
         log: &Logger,
         chain_spec: &ChainSpec,
     ) -> Result<(), BeaconChainError> {
+        metrics::inc_counter(&metrics::LIGHT_CLIENT_SERVER_CACHE_PROCESSING_REQUESTS);
         let _timer =
             metrics::start_timer(&metrics::LIGHT_CLIENT_SERVER_CACHE_RECOMPUTE_UPDATES_TIMES);
 
@@ -205,6 +206,7 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
             *self.latest_light_client_update.write() = Some(new_light_client_update);
         }
 
+        metrics::inc_counter(&metrics::LIGHT_CLIENT_SERVER_CACHE_PROCESSING_SUCCESSES);
         Ok(())
     }
 
@@ -280,6 +282,11 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
             let (sync_committee_bytes, light_client_update_bytes) = res?;
             let sync_committee_period = u64::from_ssz_bytes(&sync_committee_bytes)
                 .map_err(store::errors::Error::SszDecodeError)?;
+
+            if sync_committee_period >= start_period + count {
+                break;
+            }
+
             let epoch = sync_committee_period
                 .safe_mul(chain_spec.epochs_per_sync_committee_period.into())?;
 
@@ -290,10 +297,6 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
                     .map_err(store::errors::Error::SszDecodeError)?;
 
             light_client_updates.push(light_client_update);
-
-            if sync_committee_period >= start_period + count {
-                break;
-            }
         }
         Ok(light_client_updates)
     }

beacon_node/beacon_chain/src/metrics.rs

@@ -1972,6 +1972,22 @@ pub static LIGHT_CLIENT_SERVER_CACHE_PREV_BLOCK_CACHE_MISS: LazyLock<Result<IntC
         )
     });
 
+pub static LIGHT_CLIENT_SERVER_CACHE_PROCESSING_REQUESTS: LazyLock<Result<IntCounter>> =
+    LazyLock::new(|| {
+        try_create_int_counter(
+            "beacon_light_client_server_cache_processing_requests",
+            "Count of all requests to recompute and cache updates",
+        )
+    });
+
+pub static LIGHT_CLIENT_SERVER_CACHE_PROCESSING_SUCCESSES: LazyLock<Result<IntCounter>> =
+    LazyLock::new(|| {
+        try_create_int_counter(
+            "beacon_light_client_server_cache_processing_successes",
+            "Count of all successful requests to recompute and cache updates",
+        )
+    });
+
 /// Scrape the `beacon_chain` for metrics that are not constantly updated (e.g., the present slot,
 /// head state info, etc) and update the Prometheus `DEFAULT_REGISTRY`.
 pub fn scrape_for_metrics<T: BeaconChainTypes>(beacon_chain: &BeaconChain<T>) {