style(metrics): apply rustfmt for build_info additions

src/metrics.rs

@@ -234,6 +234,17 @@ async fn render_metrics(stats: &Stats, config: &ProxyConfig, ip_tracker: &UserIp
     let me_allows_normal = telemetry.me_level.allows_normal();
     let me_allows_debug = telemetry.me_level.allows_debug();
 
+    let _ = writeln!(
+        out,
+        "# HELP telemt_build_info Build information for the running telemt binary"
+    );
+    let _ = writeln!(out, "# TYPE telemt_build_info gauge");
+    let _ = writeln!(
+        out,
+        "telemt_build_info{{version=\"{}\"}} 1",
+        env!("CARGO_PKG_VERSION")
+    );
+
     let _ = writeln!(out, "# HELP telemt_uptime_seconds Proxy uptime");
     let _ = writeln!(out, "# TYPE telemt_uptime_seconds gauge");
     let _ = writeln!(out, "telemt_uptime_seconds {:.1}", stats.uptime_secs());
@@ -2679,6 +2690,10 @@ mod tests {
 
         let output = render_metrics(&stats, &config, &tracker).await;
 
+        assert!(output.contains(&format!(
+            "telemt_build_info{{version=\"{}\"}} 1",
+            env!("CARGO_PKG_VERSION")
+        )));
         assert!(output.contains("telemt_connections_total 2"));
         assert!(output.contains("telemt_connections_bad_total 1"));
         assert!(output.contains("telemt_handshake_timeouts_total 1"));
@@ -2768,6 +2783,7 @@ mod tests {
         let tracker = UserIpTracker::new();
         let config = ProxyConfig::default();
         let output = render_metrics(&stats, &config, &tracker).await;
+        assert!(output.contains("# TYPE telemt_build_info gauge"));
         assert!(output.contains("# TYPE telemt_uptime_seconds gauge"));
         assert!(output.contains("# TYPE telemt_connections_total counter"));
         assert!(output.contains("# TYPE telemt_connections_bad_total counter"));
@@ -2822,6 +2838,14 @@ mod tests {
                 .unwrap()
                 .contains("telemt_connections_total 3")
         );
+        assert!(
+            std::str::from_utf8(body.as_ref())
+                .unwrap()
+                .contains(&format!(
+                    "telemt_build_info{{version=\"{}\"}} 1",
+                    env!("CARGO_PKG_VERSION")
+                ))
+        );
 
         config.general.beobachten = true;
         config.general.beobachten_minutes = 10;