From 95d03b842f6fdbfda19ed050131bc95ece13a171 Mon Sep 17 00:00:00 2001
From: Jesper Jensen <jesper@jnsn.dev>
Date: Mon, 14 Apr 2025 12:22:20 +0200
Subject: Add current hash metric

It seems like it would be nice to know how many infohashes we actually
know about. Let's add a guage that tells us that directly.
---
 src/metrics.c | 10 ++++++++++
 src/metrics.h |  2 ++
 src/peers.c   |  4 ++++
 3 files changed, 16 insertions(+)

diff --git a/src/metrics.c b/src/metrics.c
index 3a56837..7bac410 100644
--- a/src/metrics.c
+++ b/src/metrics.c
@@ -8,6 +8,7 @@ prom_counter_t *bytesSent = NULL;
 
 prom_counter_t *meta = NULL;
 prom_counter_t *peers = NULL;
+prom_gauge_t *current_hashes = NULL;
 prom_counter_t *hashes = NULL;
 prom_counter_t *hash_expired = NULL;
 prom_counter_t *queries = NULL;
@@ -110,6 +111,15 @@ void metric_init() {
 		)
 	);
 
+	current_hashes = prom_collector_registry_must_register_metric(
+		prom_gauge_new(
+			"dht_live_hashes_total",
+			"Number of hashes with active peers",
+			0,
+			NULL
+		)
+	);
+
 	hashes = prom_collector_registry_must_register_metric(
 		prom_counter_new(
 			"dht_hashes_total",
diff --git a/src/metrics.h b/src/metrics.h
index 25afcce..3155ccb 100644
--- a/src/metrics.h
+++ b/src/metrics.h
@@ -10,6 +10,7 @@ extern prom_counter_t *bytesSent;
 extern prom_counter_t *meta;
 
 extern prom_counter_t *peers;
+extern prom_gauge_t *current_hashes;
 extern prom_counter_t *hashes;
 extern prom_counter_t *hash_expired;
 extern prom_counter_t *queries;
@@ -19,6 +20,7 @@ extern prom_gauge_t *activeNodes;
 extern prom_gauge_t *requestsInFlight;
 extern prom_counter_t *retries;
 
+
 extern prom_counter_t *requestsProcessed;
 
 void metric_init();
diff --git a/src/peers.c b/src/peers.c
index 781bc7e..6d23fff 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -105,6 +105,7 @@ int add_peer(struct infohash* infohash, struct addr* peer, time_t now) {
 	peer_status.peers++;
 	prom_counter_inc(peers, NULL);
 
+	prom_gauge_set(current_hashes, (double)peer_table_load, NULL);
 	return 0;
 }
 
@@ -155,6 +156,9 @@ void expire_hashes(time_t now) {
 
 		// Remove the slot
 		entry->set = false;
+		peer_table_load--;
 		prom_counter_inc(hash_expired, NULL);
 	}
+
+	prom_gauge_set(current_hashes, (double)peer_table_load, NULL);
 }
-- 
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