Export a counter of firehose connection errors

cmd/consumer/consumer.go

@@ -97,6 +97,7 @@ func (c *Consumer) run(ctx context.Context) {
 		default:
 			if err := c.runOnce(ctx); err != nil {
 				log.Error().Err(err).Msgf("Consumer of %q failed (will be restarted): %s", c.remote.Host, err)
+				connectionFailures.WithLabelValues(c.remote.Host).Inc()
 			}
 			time.Sleep(time.Second)
 		}

cmd/consumer/metrics.go

@@ -24,3 +24,8 @@ var postsByLanguageIndexed = promauto.NewCounterVec(prometheus.CounterOpts{
 	Name: "indexer_posts_by_language_count",
 	Help: "Number of posts by language",
 }, []string{"remote", "lang"})
+
+var connectionFailures = promauto.NewCounterVec(prometheus.CounterOpts{
+	Name: "consumer_connection_failures",
+	Help: "Counter of firehose connection failures",
+}, []string{"remote"})