Add sync batch state metrics (#8847)

Co-Authored-By: Jimmy Chen <jchen.tc@gmail.com>

beacon_node/network/src/sync/custody_backfill_sync/mod.rs

@@ -12,14 +12,16 @@ use lighthouse_network::{
 };
 use logging::crit;
 use std::hash::{DefaultHasher, Hash, Hasher};
+use strum::IntoEnumIterator;
 use tracing::{debug, error, info, info_span, warn};
 use types::{DataColumnSidecarList, Epoch, EthSpec};
 
+use crate::metrics;
 use crate::sync::{
     backfill_sync::{BACKFILL_EPOCHS_PER_BATCH, ProcessResult, SyncStart},
     batch::{
-        BatchConfig, BatchId, BatchInfo, BatchOperationOutcome, BatchProcessingResult, BatchState,
-        ByRangeRequestType,
+        BatchConfig, BatchId, BatchInfo, BatchMetricsState, BatchOperationOutcome,
+        BatchProcessingResult, BatchState, ByRangeRequestType,
     },
     block_sidecar_coupling::CouplingError,
     manager::CustodyBatchProcessResult,
@@ -1114,6 +1116,21 @@ impl<T: BeaconChainTypes> CustodyBackFillSync<T> {
         *self.network_globals.custody_sync_state.write() = state;
     }
 
+    pub fn register_metrics(&self) {
+        for state in BatchMetricsState::iter() {
+            let count = self
+                .batches
+                .values()
+                .filter(|b| b.state().metrics_state() == state)
+                .count();
+            metrics::set_gauge_vec(
+                &metrics::SYNCING_CHAIN_BATCHES,
+                &["custody_backfill", state.into()],
+                count as i64,
+            );
+        }
+    }
+
     /// A fully synced peer has joined us.
     /// If we are in a failed state, update a local variable to indicate we are able to restart
     /// the failed sync on the next attempt.