From 71f7a444398275923246e1bc8283938a63a8267a Mon Sep 17 00:00:00 2001
From: bndw <ben@bdw.to>
Date: Sun, 15 Feb 2026 08:22:03 -0800
Subject: feat: add metrics for blocked events

Track and display blocked event counts with per-kind breakdown.

- Add events_blocked_total counter with kind label
- Add RecordBlockedEvent method to metrics
- Display blocked count in dashboard Storage section
- Call metric when rejecting non-core protocol kinds

Allows monitoring spam patterns and verifying kind filter effectiveness.
Raw metrics show breakdown by kind (e.g., kind=20001, kind=30311).
---
 internal/handler/websocket/handler.go |  4 ++++
 internal/metrics/dashboard.html       |  7 +++++++
 internal/metrics/metrics.go           | 17 +++++++++++++++++
 3 files changed, 28 insertions(+)

(limited to 'internal')

diff --git a/internal/handler/websocket/handler.go b/internal/handler/websocket/handler.go
index 8daa89f..35d0aea 100644
--- a/internal/handler/websocket/handler.go
+++ b/internal/handler/websocket/handler.go
@@ -33,6 +33,7 @@ type MetricsRecorder interface {
 	DecrementSubscriptions()
 	SetActiveSubscriptions(count int)
 	RecordRequest(method, status string, duration float64)
+	RecordBlockedEvent(kind int32)
 }
 
 type RateLimiter interface {
@@ -302,6 +303,9 @@ func (h *Handler) handleEvent(ctx context.Context, conn *websocket.Conn, raw []j
 	// Reject non-core protocol kinds (spam, ephemeral, chat)
 	if !isAllowedKind(pbEvent.Kind) {
 		status = "ok"
+		if h.metrics != nil {
+			h.metrics.RecordBlockedEvent(pbEvent.Kind)
+		}
 		h.sendOK(ctx, conn, event.ID, true, "rejected: kind not supported")
 		return nil
 	}
diff --git a/internal/metrics/dashboard.html b/internal/metrics/dashboard.html
index 9538ac6..1fa1ddf 100644
--- a/internal/metrics/dashboard.html
+++ b/internal/metrics/dashboard.html
@@ -199,6 +199,10 @@
                     <span class="metric-label">Deletions</span>
                     <span class="metric-value" id="event_deletions">0</span>
                 </div>
+                <div class="metric">
+                    <span class="metric-label">Blocked</span>
+                    <span class="metric-value" id="events_blocked">0</span>
+                </div>
             </div>
 
             <div class="card">
@@ -317,6 +321,9 @@
                 document.getElementById('event_deletions').textContent =
                     sumMetric(metrics, `${prefix}_relay_event_deletions_total`);
 
+                document.getElementById('events_blocked').textContent =
+                    sumMetric(metrics, `${prefix}_relay_events_blocked_total`);
+
                 const durationSum = sumMetric(metrics, `${prefix}_relay_request_duration_seconds_sum`);
                 const durationCount = sumMetric(metrics, `${prefix}_relay_request_duration_seconds_count`);
                 const avgLatencyMs = durationCount > 0 ? (durationSum / durationCount * 1000) : 0;
diff --git a/internal/metrics/metrics.go b/internal/metrics/metrics.go
index 74f9ffb..dea0748 100644
--- a/internal/metrics/metrics.go
+++ b/internal/metrics/metrics.go
@@ -2,6 +2,7 @@ package metrics
 
 import (
 	_ "embed"
+	"fmt"
 	"net/http"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -30,6 +31,7 @@ type Metrics struct {
 	eventsTotal         prometheus.Gauge
 	dbSizeBytes         prometheus.Gauge
 	eventDeletionsTotal prometheus.Counter
+	eventsBlockedTotal  *prometheus.CounterVec
 
 	// Config
 	config *Config
@@ -195,6 +197,16 @@ func New(config *Config) *Metrics {
 		},
 	)
 
+	m.eventsBlockedTotal = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: config.Namespace,
+			Subsystem: config.Subsystem,
+			Name:      "events_blocked_total",
+			Help:      "Total events blocked by kind filter",
+		},
+		[]string{"kind"},
+	)
+
 	return m
 }
 
@@ -274,6 +286,11 @@ func (m *Metrics) RecordEventDeletion() {
 	m.eventDeletionsTotal.Inc()
 }
 
+// RecordBlockedEvent records an event blocked by kind filter.
+func (m *Metrics) RecordBlockedEvent(kind int32) {
+	m.eventsBlockedTotal.WithLabelValues(fmt.Sprintf("%d", kind)).Inc()
+}
+
 // RequestStatus represents the status of a request for metrics.
 type RequestStatus string
 
-- 
cgit v1.2.3