feat: add prometheus monitor

Cargo.lock

@@ -1731,6 +1731,7 @@ dependencies = [
  "phf",
  "reqwest",
  "rocket",
+ "rocket_prometheus",
  "serde",
  "serde_json",
  "serde_yaml",
@@ -1982,6 +1983,20 @@ dependencies = [
  "yansi 1.0.0-rc.1",
 ]
 
+[[package]]
+name = "prometheus"
+version = "0.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "449811d15fbdf5ceb5c1144416066429cf82316e2ec8ce0c1f6f8a02e7bbcf8c"
+dependencies = [
+ "cfg-if",
+ "fnv",
+ "lazy_static",
+ "memchr",
+ "parking_lot",
+ "thiserror",
+]
+
 [[package]]
 name = "prost"
 version = "0.11.9"
@@ -2273,6 +2288,16 @@ dependencies = [
  "uncased",
 ]
 
+[[package]]
+name = "rocket_prometheus"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18faabccdfcd08d4501768f5b6936f6332af10496f1ea8107eb48a7766e03439"
+dependencies = [
+ "prometheus",
+ "rocket",
+]
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.23"

Cargo.toml

@@ -17,6 +17,7 @@ async-trait = "0.1.74"
 async-mutex = "1.4.0"
 tokio = { version = "1.34.0", features = ["macros"] }
 tracing = { version = "0.1.40", features = ["attributes", "std"] }
+rocket_prometheus = "0.10.0"
 yansi = "0.5.1"
 tera = "1.19.1"
 tempfile = "3.8.1"

src/lib.rs

@@ -1,6 +1,7 @@
 use chromium::rocket::Chromium;
 use nanobyte_opentelemetry::rocket::TracingFairing;
 use rocket::{Rocket, Build, routes, fairing::AdHoc};
+use rocket_prometheus::PrometheusMetrics;
 use serde::Deserialize;
 pub mod routes;
 mod chromium;
@@ -24,6 +25,8 @@ pub struct DefaultPerson {
 }
 
 pub fn rocket_builder() -> Rocket<Build> {
+    let prometheus = PrometheusMetrics::new();
+
     rocket::build()
         .attach(TracingFairing::ignite())
         .attach(Chromium::ignite())
@@ -33,8 +36,10 @@ pub fn rocket_builder() -> Rocket<Build> {
         .attach(
             AdHoc::config::<DefaultPerson>()
         )
+        .attach(prometheus.clone())
         .mount("/", routes![
             routes::pdf::render_pdf_cv,
             routes::pdf::render_html_cv
         ])
+        .mount("/metrics", prometheus)
 }