Add Prometheus metrics

src/metrics.ts

@@ -0,0 +1,58 @@
+import { Counter } from 'prom-client';
+
+export const httpRequestCounter = new Counter({
+  name: 'http_requests_total',
+  help: 'Total number of HTTP requests',
+  labelNames: ['method', 'path'],
+});
+
+export const fetchCounter = new Counter({
+  name: 'fetch_total',
+  help: 'Total number of fetch requests',
+  labelNames: ['method', 'path'],
+});
+
+export const firehoseEventCounter = new Counter({
+  name: 'firehose_events_total',
+  help: 'Total number of Nostr events processed by the firehose',
+  labelNames: ['kind'],
+});
+
+export const pipelineEventCounter = new Counter({
+  name: 'pipeline_events_total',
+  help: 'Total number of Nostr events processed by the pipeline',
+  labelNames: ['kind'],
+});
+
+export const relayReqCounter = new Counter({
+  name: 'relay_reqs_total',
+  help: 'Total number of REQ messages processed by the relay',
+});
+
+export const relayEventCounter = new Counter({
+  name: 'relay_events_total',
+  help: 'Total number of EVENT messages processed by the relay',
+  labelNames: ['kind'],
+});
+
+export const relayCountCounter = new Counter({
+  name: 'relay_counts_total',
+  help: 'Total number of COUNT messages processed by the relay',
+});
+
+export const relayMessageCounter = new Counter({
+  name: 'relay_messages_total',
+  help: 'Total number of Nostr messages processed by the relay',
+});
+
+export const dbQueryCounter = new Counter({
+  name: 'db_query_total',
+  help: 'Total number of database queries',
+  labelNames: ['kind'],
+});
+
+export const dbEventCounter = new Counter({
+  name: 'db_events_total',
+  help: 'Total number of database inserts',
+  labelNames: ['kind'],
+});