add disk I/O stats

2 files changed, 44 insertions, 0 deletions

diff --git a/src/api/stats.rs b/src/api/stats.rs
index 838cc0f..6c5e172 100644
--- a/src/api/stats.rs
+++ b/src/api/stats.rs
@@ -35,6 +35,18 @@ pub(crate) struct StatsResponse {
     /// The peers listed in /peers together (a forgotten peer's are gone).
     incidents: Incidents,
     propagation: PropagationStats,
+    disk: DiskStats,
+}
+
+/// Files this node reads and writes for itself (the state file, a backup to recover
+/// from), since it started.
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+struct DiskStats {
+    reads: u64,
+    read_bytes: u64,
+    writes: u64,
+    written_bytes: u64,
 }
 
 /// How long changes written elsewhere took from their commit there until applied here,
@@ -195,5 +207,11 @@ async fn collect(state: &AppState) -> StatsResponse {
                 .map(|(le_ms, count)| PropagationBucket { le_ms, count })
                 .collect(),
         },
+        disk: DiskStats {
+            reads: node.disk.reads,
+            read_bytes: node.disk.read_bytes,
+            writes: node.disk.writes,
+            written_bytes: node.disk.written_bytes,
+        },
     }
 }
diff --git a/src/api/stats/prometheus.rs b/src/api/stats/prometheus.rs
index f68ca85..ea97bd2 100644
--- a/src/api/stats/prometheus.rs
+++ b/src/api/stats/prometheus.rs
@@ -297,6 +297,32 @@ pub(super) async fn render(state: &AppState, stats: &StatsResponse) -> String {
         stats.stale_hello_replies as f64,
     );
 
+    let disk = &stats.disk;
+    out.single(
+        "disk_reads_total",
+        "counter",
+        "Files this node read for itself (state file, backup).",
+        disk.reads as f64,
+    );
+    out.single(
+        "disk_read_bytes_total",
+        "counter",
+        "Bytes of those files.",
+        disk.read_bytes as f64,
+    );
+    out.single(
+        "disk_writes_total",
+        "counter",
+        "Files this node wrote for itself (state file).",
+        disk.writes as f64,
+    );
+    out.single(
+        "disk_written_bytes_total",
+        "counter",
+        "Bytes of those files.",
+        disk.written_bytes as f64,
+    );
+
     let propagation = &stats.propagation;
     out.family(
         "propagation_delay_seconds",