Sgl-router Prometheus metrics endpoint and usage track metrics (#6537)

sgl-router/src/prometheus.rs

@@ -0,0 +1,40 @@
+use metrics_exporter_prometheus::{Matcher, PrometheusBuilder};
+use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+use std::time::Duration;
+
+#[derive(Debug, Clone)]
+pub struct PrometheusConfig {
+    pub port: u16,
+    pub host: String,
+}
+
+impl Default for PrometheusConfig {
+    fn default() -> Self {
+        Self {
+            port: 29000,
+            host: "0.0.0.0".to_string(),
+        }
+    }
+}
+
+pub fn start_prometheus(config: PrometheusConfig) {
+    let duration_matcher = Matcher::Suffix(String::from("duration"));
+    let duration_bucket = [
+        0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 30.0, 45.0,
+        60.0, 90.0, 120.0, 180.0, 240.0,
+    ];
+
+    let ip_addr: IpAddr = config
+        .host
+        .parse()
+        .unwrap_or(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)));
+    let socket_addr = SocketAddr::new(ip_addr, config.port);
+
+    PrometheusBuilder::new()
+        .with_http_listener(socket_addr)
+        .upkeep_timeout(Duration::from_secs(5 * 60))
+        .set_buckets_for_metric(duration_matcher, &duration_bucket)
+        .expect("failed to set duration bucket")
+        .install()
+        .expect("failed to install Prometheus metrics exporter");
+}