fix(rust/cardano-chain-follower): Fixing missing updating mithril stats with the new snapshot (#467)

* update new_mithril_update and live_sync_backfill_and_purge

* wip

* wip

Author: Mr-Leshiy

rust/cardano-chain-follower/src/chain_sync.rs

@@ -451,13 +451,13 @@ async fn live_sync_backfill_and_purge(
         return;
     };
 
+    stats::new_mithril_update(cfg.chain, update.tip.slot_or_default());
+
     debug!(
         "Before Backfill: Size of the Live Chain is: {} Blocks",
         live_chain_length(cfg.chain)
     );
 
-    let live_chain_head: Point;
-
     loop {
         // We will re-attempt backfill, until its successful.
         // Backfill is atomic, it either fully works, or none of the live-chain is changed.
@@ -467,23 +467,15 @@ async fn live_sync_backfill_and_purge(
             sleep(Duration::from_secs(10)).await;
         }
 
-        if let Some(head_point) = get_live_head_point(cfg.chain) {
-            live_chain_head = head_point;
+        if get_live_head_point(cfg.chain).is_some() {
             break;
         }
     }
 
-    stats::new_mithril_update(
-        cfg.chain,
-        update.tip.slot_or_default(),
-        live_chain_length(cfg.chain) as u64,
-        live_chain_head.slot_or_default(),
-    );
+    let new_live_chain_length = live_chain_length(cfg.chain);
+    stats::new_live_total_blocks(cfg.chain, new_live_chain_length as u64);
 
-    debug!(
-        "After Backfill: Size of the Live Chain is: {} Blocks",
-        live_chain_length(cfg.chain)
-    );
+    debug!("After Backfill: Size of the Live Chain is: {new_live_chain_length} Blocks",);
 
     // Once Backfill is completed OK we can use the Blockchain data for Syncing and Querying
     sync_ready.signal();
@@ -501,6 +493,8 @@ async fn live_sync_backfill_and_purge(
             update_sender = get_chain_update_tx_queue(cfg.chain).await;
         }
 
+        stats::new_mithril_update(cfg.chain, update.tip.slot_or_default());
+
         debug!("Mithril Tip has advanced to: {update:?} : PURGE NEEDED");
 
         let update_point: Point = update.tip.clone();
@@ -510,9 +504,11 @@ async fn live_sync_backfill_and_purge(
             error!("Mithril Purge Failed: {}", error);
         }
 
+        let new_live_chain_length = live_chain_length(cfg.chain);
+        stats::new_live_total_blocks(cfg.chain, new_live_chain_length as u64);
+
         debug!(
-            "After Purge: Size of the Live Chain is: {} Blocks: Triggering Sleeping Followers.",
-            live_chain_length(cfg.chain)
+            "After Purge: Size of the Live Chain is: {new_live_chain_length} Blocks: Triggering Sleeping Followers.",
         );
 
         // Trigger any sleeping followers that data has changed.

rust/cardano-chain-follower/src/stats/mod.rs

@@ -193,8 +193,6 @@ pub(crate) fn new_live_block(
 pub(crate) fn new_mithril_update(
     chain: Network,
     mithril_tip: Slot,
-    total_live_blocks: u64,
-    tip_slot: Slot,
 ) {
     // This will actually always succeed.
     let Some(stats) = lookup_stats(chain) else {
@@ -209,8 +207,25 @@ pub(crate) fn new_mithril_update(
 
     chain_stats.mithril.updates = chain_stats.mithril.updates.saturating_add(1);
     chain_stats.mithril.tip = mithril_tip;
+}
+
+/// Track the current total live blocks count
+pub(crate) fn new_live_total_blocks(
+    chain: Network,
+    total_live_blocks: u64,
+) {
+    // This will actually always succeed.
+    let Some(stats) = lookup_stats(chain) else {
+        return;
+    };
+
+    let Ok(mut chain_stats) = stats.write() else {
+        // Worst case if this fails (it never should) is we stop updating stats.
+        error!("Stats RwLock should never be able to error.");
+        return;
+    };
+
     chain_stats.live.blocks = total_live_blocks;
-    chain_stats.live.tip = tip_slot;
 }
 
 /// When did we start the backfill.