From b27dc0dc151a37a50b2917a2862c60e0d2341f90 Mon Sep 17 00:00:00 2001
From: auricom <27022259+auricom@users.noreply.github.com>
Date: Mon, 22 Dec 2025 09:25:05 +0100
Subject: [PATCH 1/2] fix: ensure time_since_last_block accuracy with polling
 fallback

---
 pkg/exporters/drift/drift.go |  7 +++++++
 pkg/metrics/metrics.go       | 12 ++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/pkg/exporters/drift/drift.go b/pkg/exporters/drift/drift.go
index 58799da..9384352 100644
--- a/pkg/exporters/drift/drift.go
+++ b/pkg/exporters/drift/drift.go
@@ -61,6 +61,9 @@ func (e exporter) ExportMetrics(ctx context.Context, m *metrics.Metrics) error {
 
 			m.RecordEndpointAvailability(e.chainID, e.referenceNode, true)
 			m.RecordReferenceBlockHeight(e.chainID, e.referenceNode, refHeight)
+			// Also update time since last block metric when we see new blocks via polling
+			// This ensures the metric stays accurate even if WebSocket subscription fails
+			m.UpdateLastBlockTime(e.chainID, time.Now())
 			e.logger.Info().Uint64("height", refHeight).Str("endpoint", e.referenceNode).Msg("recorded reference node height")
 
 			// get each full node height and calculate drift
@@ -77,6 +80,10 @@ func (e exporter) ExportMetrics(ctx context.Context, m *metrics.Metrics) error {
 				m.RecordCurrentBlockHeight(e.chainID, fullNode, currentHeight)
 				m.RecordBlockHeightDrift(e.chainID, fullNode, refHeight, currentHeight)
 
+				// Also update time since last block metric when we see new blocks via polling
+				// This ensures the metric stays accurate even if WebSocket subscription fails
+				m.UpdateLastBlockTime(e.chainID, time.Now())
+
 				drift := int64(refHeight) - int64(currentHeight)
 				e.logger.Info().
 					Uint64("ref_height", refHeight).
diff --git a/pkg/metrics/metrics.go b/pkg/metrics/metrics.go
index 6c7c885..cce4ce7 100644
--- a/pkg/metrics/metrics.go
+++ b/pkg/metrics/metrics.go
@@ -568,6 +568,18 @@ func (m *Metrics) RecordBlockTime(chainID string, arrivalTime time.Time) {
 	m.TimeSinceLastBlock.WithLabelValues(chainID).Set(0)
 }
 
+// UpdateLastBlockTime updates the last block arrival time and resets time since last block metric
+// without recording block time histogram. This is used by pollers that can't measure inter-block time.
+func (m *Metrics) UpdateLastBlockTime(chainID string, arrivalTime time.Time) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	// update last seen arrival time
+	m.lastBlockArrivalTime[chainID] = arrivalTime
+	// reset time since last block to 0
+	m.TimeSinceLastBlock.WithLabelValues(chainID).Set(0)
+}
+
 // UpdateTimeSinceLastBlock updates the time_since_last_block metric for all chains
 // should be called periodically to keep the metric current.
 func (m *Metrics) UpdateTimeSinceLastBlock() {

From 2566db18f1b70f8b932d642525a2e57194297cbf Mon Sep 17 00:00:00 2001
From: auricom <27022259+auricom@users.noreply.github.com>
Date: Mon, 22 Dec 2025 11:09:22 +0100
Subject: [PATCH 2/2] gemini assist

---
 pkg/metrics/metrics.go | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/pkg/metrics/metrics.go b/pkg/metrics/metrics.go
index cce4ce7..4de801e 100644
--- a/pkg/metrics/metrics.go
+++ b/pkg/metrics/metrics.go
@@ -562,10 +562,7 @@ func (m *Metrics) RecordBlockTime(chainID string, arrivalTime time.Time) {
 		}
 	}
 
-	// update last seen arrival time
-	m.lastBlockArrivalTime[chainID] = arrivalTime
-	// reset time since last block to 0
-	m.TimeSinceLastBlock.WithLabelValues(chainID).Set(0)
+	m.updateLastBlockTimeUnsafe(chainID, arrivalTime)
 }
 
 // UpdateLastBlockTime updates the last block arrival time and resets time since last block metric
@@ -573,7 +570,13 @@ func (m *Metrics) RecordBlockTime(chainID string, arrivalTime time.Time) {
 func (m *Metrics) UpdateLastBlockTime(chainID string, arrivalTime time.Time) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
+	m.updateLastBlockTimeUnsafe(chainID, arrivalTime)
+}
 
+// updateLastBlockTimeUnsafe is an unexported helper that updates the last block arrival time
+// and resets the time since last block gauge.
+// This function is not thread-safe and should be called with a lock held.
+func (m *Metrics) updateLastBlockTimeUnsafe(chainID string, arrivalTime time.Time) {
 	// update last seen arrival time
 	m.lastBlockArrivalTime[chainID] = arrivalTime
 	// reset time since last block to 0