feat: add metrics server and http metrics (#1394)

* feat: add metrics server and http metrics

* setup metrics

* update default config

* fix tests

1 files changed, 26 insertions, 1 deletions

diff --git a/atuin-server/src/lib.rs b/atuin-server/src/lib.rs
index 6778b099..2d2a9c78 100644
--- a/atuin-server/src/lib.rs
+++ b/atuin-server/src/lib.rs
@@ -3,16 +3,20 @@
 use std::{future::Future, net::TcpListener};
 
 use atuin_server_database::Database;
+use axum::Router;
 use axum::Server;
 use eyre::{Context, Result};
 
 mod handlers;
+mod metrics;
 mod router;
-mod settings;
 mod utils;
 
 pub use settings::example_config;
 pub use settings::Settings;
+
+pub mod settings;
+
 use tokio::signal;
 
 #[cfg(target_family = "unix")]
@@ -70,3 +74,24 @@ pub async fn launch_with_listener<Db: Database>(
 
     Ok(())
 }
+
+// The separate listener means it's much easier to ensure metrics are not accidentally exposed to
+// the public.
+pub async fn launch_metrics_server(host: String, port: u16) -> Result<()> {
+    let listener = TcpListener::bind((host, port)).context("failed to bind metrics tcp")?;
+
+    let recorder_handle = metrics::setup_metrics_recorder();
+
+    let router = Router::new().route(
+        "/metrics",
+        axum::routing::get(move || std::future::ready(recorder_handle.render())),
+    );
+
+    Server::from_tcp(listener)
+        .context("could not launch server")?
+        .serve(router.into_make_service())
+        .with_graceful_shutdown(shutdown_signal())
+        .await?;
+
+    Ok(())
+}