From 97a110a7f8b26942cf8764fbdd66849f3ff70265 Mon Sep 17 00:00:00 2001
From: Anxo Rodriguez <anxolin@gmail.com>
Date: Sat, 7 Dec 2024 14:38:46 +0000
Subject: [PATCH] feat: add metric for the latest block from the chain (tip)

---
 src/services/chain.ts | 10 ++++++++++
 src/utils/metrics.ts  |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/src/services/chain.ts b/src/services/chain.ts
index d030e4f..940f18e 100644
--- a/src/services/chain.ts
+++ b/src/services/chain.ts
@@ -189,7 +189,11 @@ export class ChainContext {
     let fromBlock = lastProcessedBlock
       ? lastProcessedBlock.number + 1
       : this.deploymentBlock;
+
     let currentBlock = await provider.getBlock("latest");
+    metrics.blockHeightLatest
+      .labels(chainId.toString())
+      .set(currentBlock.number);
 
     let printSyncInfo = true; // Print sync info only once
     let toBlock: "latest" | number = 0;
@@ -199,6 +203,9 @@ export class ChainContext {
         if (typeof toBlock === "number" && toBlock > currentBlock.number) {
           // refresh the current block
           currentBlock = await provider.getBlock("latest");
+          metrics.blockHeightLatest
+            .labels(chainId.toString())
+            .set(currentBlock.number);
           toBlock =
             toBlock > currentBlock.number ? currentBlock.number : toBlock;
 
@@ -283,6 +290,9 @@ export class ChainContext {
       // It may have taken some time to process the blocks, so refresh the current block number
       // and check if we are in sync
       currentBlock = await provider.getBlock("latest");
+      metrics.blockHeightLatest
+        .labels(chainId.toString())
+        .set(currentBlock.number);
 
       // If we are in sync, let it be known
       const lastProcessedBlockNumber = lastProcessedBlock?.number || 0;
diff --git a/src/utils/metrics.ts b/src/utils/metrics.ts
index d2bfdd1..79b70f3 100644
--- a/src/utils/metrics.ts
+++ b/src/utils/metrics.ts
@@ -57,6 +57,12 @@ export const blockHeight = new client.Gauge({
   labelNames: ["chain_id"],
 });
 
+export const blockHeightLatest = new client.Gauge({
+  name: "watch_tower_block_height_latest",
+  help: "Block height of the last block (tip of the chain)",
+  labelNames: ["chain_id"],
+});
+
 export const reorgDepth = new client.Gauge({
   name: "watch_tower_latest_reorg_depth",
   help: "Depth of the most recent reorg",