From e3b558b64239b5b153071c8ece5dedef0f1f1a19 Mon Sep 17 00:00:00 2001
From: ilya <ilya@cow.fi>
Date: Fri, 17 Nov 2023 10:22:44 +0000
Subject: [PATCH] Healthz endpoints for Driver and Solvers (#2060)

# Description
Adds liveness endpoints for `driver` and `solvers` crates.

# Changes
2 new GET endpoints always returning `200OK`

## How to test
Will be tested in scope of the
https://github.com/cowprotocol/infrastructure/pull/858 deployment

## Related Issues

Fixes #1382
---
 crates/driver/src/infra/api/mod.rs            | 3 ++-
 crates/driver/src/infra/api/routes/healthz.rs | 9 +++++++++
 crates/driver/src/infra/api/routes/mod.rs     | 2 ++
 crates/solvers/src/api/mod.rs                 | 1 +
 crates/solvers/src/api/routes/healthz.rs      | 5 +++++
 crates/solvers/src/api/routes/mod.rs          | 3 ++-
 6 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 crates/driver/src/infra/api/routes/healthz.rs
 create mode 100644 crates/solvers/src/api/routes/healthz.rs

diff --git a/crates/driver/src/infra/api/mod.rs b/crates/driver/src/infra/api/mod.rs
index 7dc4794ca1..5f078c6490 100644
--- a/crates/driver/src/infra/api/mod.rs
+++ b/crates/driver/src/infra/api/mod.rs
@@ -43,8 +43,9 @@ impl Api {
         let tokens = tokens::Fetcher::new(self.eth.clone());
         let pre_processor = domain::competition::AuctionProcessor::new(Arc::new(self.eth.clone()));
 
-        // Add the metrics endpoint.
+        // Add the metrics and healthz endpoints.
         app = routes::metrics(app);
+        app = routes::healthz(app);
 
         // Multiplex each solver as part of the API. Multiple solvers are multiplexed
         // on the same driver so only one liquidity collector collects the liquidity
diff --git a/crates/driver/src/infra/api/routes/healthz.rs b/crates/driver/src/infra/api/routes/healthz.rs
new file mode 100644
index 0000000000..157f557a93
--- /dev/null
+++ b/crates/driver/src/infra/api/routes/healthz.rs
@@ -0,0 +1,9 @@
+use axum::{http::StatusCode, response::IntoResponse, routing::get};
+
+pub(in crate::infra::api) fn healthz(app: axum::Router<()>) -> axum::Router<()> {
+    app.route("/healthz", get(route))
+}
+
+async fn route() -> impl IntoResponse {
+    StatusCode::OK
+}
diff --git a/crates/driver/src/infra/api/routes/mod.rs b/crates/driver/src/infra/api/routes/mod.rs
index d1661dab2e..ee1027b0e9 100644
--- a/crates/driver/src/infra/api/routes/mod.rs
+++ b/crates/driver/src/infra/api/routes/mod.rs
@@ -1,3 +1,4 @@
+mod healthz;
 mod info;
 mod metrics;
 mod quote;
@@ -6,6 +7,7 @@ mod settle;
 mod solve;
 
 pub(super) use {
+    healthz::healthz,
     info::info,
     metrics::metrics,
     quote::{quote, OrderError},
diff --git a/crates/solvers/src/api/mod.rs b/crates/solvers/src/api/mod.rs
index b5c4bbf1a8..12e8619592 100644
--- a/crates/solvers/src/api/mod.rs
+++ b/crates/solvers/src/api/mod.rs
@@ -20,6 +20,7 @@ impl Api {
         shutdown: impl Future<Output = ()> + Send + 'static,
     ) -> Result<(), hyper::Error> {
         let app = axum::Router::new()
+            .route("/healthz", axum::routing::get(routes::healthz))
             .route("/solve", axum::routing::post(routes::solve))
             .route("/notify", axum::routing::post(routes::notify))
             .layer(
diff --git a/crates/solvers/src/api/routes/healthz.rs b/crates/solvers/src/api/routes/healthz.rs
new file mode 100644
index 0000000000..7e39e585dc
--- /dev/null
+++ b/crates/solvers/src/api/routes/healthz.rs
@@ -0,0 +1,5 @@
+use axum::{http::StatusCode, response::IntoResponse};
+
+pub async fn healthz() -> impl IntoResponse {
+    StatusCode::OK
+}
diff --git a/crates/solvers/src/api/routes/mod.rs b/crates/solvers/src/api/routes/mod.rs
index 6c051cfc9f..0628449625 100644
--- a/crates/solvers/src/api/routes/mod.rs
+++ b/crates/solvers/src/api/routes/mod.rs
@@ -1,9 +1,10 @@
 use serde::Serialize;
 
+mod healthz;
 mod notify;
 mod solve;
 
-pub(super) use {notify::notify, solve::solve};
+pub(super) use {healthz::healthz, notify::notify, solve::solve};
 
 #[derive(Debug, Serialize)]
 #[serde(untagged)]