From 58eef6b3fa7be4ce955b1e4dac0754b8edd669b7 Mon Sep 17 00:00:00 2001
From: Aravinth Manivannan <realaravinth@batsense.net>
Date: Sun, 25 Dec 2022 13:14:00 +0530
Subject: [PATCH] feat: add prometheus instrumentation

---
 Cargo.lock  | 27 +++++++++++++++++++++++++++
 Cargo.toml  |  1 +
 src/main.rs |  7 +++++++
 3 files changed, 35 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 3d0fa2e..7764663 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -208,6 +208,18 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "actix-web-prom"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9df3127d20a5d01c9fc9aceb969a38d31a6767e1b48a54d55a8f56c769a84923"
+dependencies = [
+ "actix-web",
+ "futures-core",
+ "pin-project-lite",
+ "prometheus",
+]
+
 [[package]]
 name = "adler"
 version = "1.0.2"
@@ -415,6 +427,7 @@ dependencies = [
  "actix-web",
  "actix-web-codegen-const-routes",
  "actix-web-httpauth",
+ "actix-web-prom",
  "base64",
  "clap",
  "config",
@@ -1408,6 +1421,20 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[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 0.12.1",
+ "thiserror",
+]
+
 [[package]]
 name = "quick-error"
 version = "1.2.3"
diff --git a/Cargo.toml b/Cargo.toml
index d606f73..88a48ca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ build = "build.rs"
 
 [dependencies]
 actix-web = "4"
+actix-web-prom = "0.6.0"
 futures-util = { version = "0.3.17", default-features = false, features = ["std"] }
 lazy_static = "1.4.0"
 log = "0.4.17"
diff --git a/src/main.rs b/src/main.rs
index ddecbc0..4053369 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,6 +19,7 @@ use std::env;
 use actix_web::http::StatusCode;
 use actix_web::web::JsonConfig;
 use actix_web::{error::InternalError, middleware, App, HttpServer};
+use actix_web_prom::PrometheusMetricsBuilder;
 use clap::{Parser, Subcommand};
 use log::info;
 
@@ -112,6 +113,11 @@ async fn serve(settings: Settings, ctx: AppCtx) -> std::io::Result<()> {
     let ip = settings.server.get_ip();
     println!("Starting server on: http://{ip}");
 
+    let prometheus = PrometheusMetricsBuilder::new("api")
+        .endpoint("/metrics")
+        .build()
+        .unwrap();
+
     HttpServer::new(move || {
         App::new()
             .wrap(middleware::Logger::default())
@@ -124,6 +130,7 @@ async fn serve(settings: Settings, ctx: AppCtx) -> std::io::Result<()> {
                 middleware::TrailingSlash::Trim,
             ))
             .app_data(get_json_err())
+            .wrap(prometheus.clone())
             .configure(routes::services)
     })
     .bind(ip)?