chore(redis): add redis connection and error metrics

src/cache/redis-kv-store.ts

@@ -19,6 +19,7 @@ import { RedisClientType, commandOptions, createClient } from 'redis';
 import winston from 'winston';
 
 import * as config from '../config.js';
+import * as metrics from '../metrics.js';
 import { KVBufferStore } from '../types.js';
 
 export class RedisKvStore implements KVBufferStore {
@@ -45,14 +46,14 @@ export class RedisKvStore implements KVBufferStore {
         message: error.message,
         stack: error.stack,
       });
-      // TODO: add prometheus metric for redis error
+      metrics.redisErrors.inc({ error: error.message });
     });
     this.client.connect().catch((error: any) => {
       this.log.error(`Redis connection error`, {
         message: error.message,
         stack: error.stack,
       });
-      // TODO: add prometheus metric for redis connection error
+      metrics.redisConnectionError.inc();
     });
   }
 

src/metrics.ts

@@ -19,6 +19,7 @@ import * as promClient from 'prom-client';
 
 export const metrics = new promClient.Registry();
 
+// ARNS cache metrics
 export const arnsCacheHit = new promClient.Counter({
   name: 'arns_cache_hit',
   help: 'Number of times the ARNS cache was hit',
@@ -30,3 +31,15 @@ export const arnsCacheMiss = new promClient.Counter({
   help: 'Number of times the ARNS cache was missed',
   labelNames: ['cache_type'],
 });
+
+// Redis metrics
+export const redisConnectionError = new promClient.Gauge({
+  name: 'redis_connection_error',
+  help: 'Redis connection error',
+});
+
+export const redisErrors = new promClient.Counter({
+  name: 'redis_errors',
+  help: 'Redis errors',
+  labelNames: ['error'],
+});