feat: add health check server

Cargo.toml

@@ -44,3 +44,4 @@ clap = { version = "4.5", features = ["derive"] }
 ctor = "0.2.8"
 tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+axum = "0.6.0"

src/config.rs

@@ -10,6 +10,12 @@ pub struct Config {
     pub coordinator: CoordinatorConfig,
     pub l2geth: Option<L2GethConfig>,
     pub prover: ProverConfig,
+    #[serde(default = "default_health_listener_addr")]
+    pub health_listener_addr: String,
+}
+
+fn default_health_listener_addr() -> String {
+    "0.0.0.0:80".to_string()
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone)]

src/coordinator_handler/coordinator_client.rs

@@ -73,7 +73,7 @@ impl CoordinatorClient {
     ///
     /// If the token is expired, `force_relogin` is set to `true`, or a login was never performed
     /// before, it will authenticate and fetch a new token.
-    async fn get_token(&self, force_relogin: bool) -> anyhow::Result<String> {
+    pub async fn get_token(&self, force_relogin: bool) -> anyhow::Result<String> {
         let token_guard = self.token.lock().await;
 
         match *token_guard {

src/prover/builder.rs

@@ -92,6 +92,7 @@ impl ProverBuilder {
             l2geth_client,
             proving_service: self.proving_service.unwrap(),
             n_workers: self.cfg.prover.n_workers,
+            health_listener_addr: self.cfg.health_listener_addr,
         })
     }
 }

src/prover/mod.rs

@@ -8,10 +8,14 @@ use crate::{
     },
     tracing_handler::L2gethClient,
 };
+use axum::{routing::get, Router};
 use proving_service::{ProveRequest, QueryTaskRequest, TaskStatus};
+use std::net::SocketAddr;
+use std::str::FromStr;
 use tokio::task::JoinSet;
 use tokio::time::{sleep, Duration};
 use tracing::{error, info, instrument};
+
 pub use {builder::ProverBuilder, proving_service::ProvingService, types::*};
 
 const WORKER_SLEEP_SEC: u64 = 20;
@@ -23,6 +27,7 @@ pub struct Prover {
     l2geth_client: Option<L2gethClient>,
     proving_service: Box<dyn ProvingService + Send + Sync>,
     n_workers: usize,
+    health_listener_addr: String,
 }
 
 impl Prover {
@@ -32,6 +37,19 @@ impl Prover {
             assert!(self.l2geth_client.is_some());
         }
 
+        // Use the first coordinator client to test the connection
+        match self.coordinator_clients[0].get_token(true).await {
+            Ok(_) => {}
+            Err(e) => {
+                panic!("Failed to login: {:?}", e);
+            }
+        };
+
+        let app = Router::new().route("/", get(|| async { "OK" }));
+        let addr = SocketAddr::from_str(&self.health_listener_addr).expect("Failed to parse socket address");
+        let server = axum::Server::bind(&addr).serve(app.into_make_service());
+        let health_check_server_task = tokio::spawn(server);
+
         let mut provers = JoinSet::new();
         let self_arc = std::sync::Arc::new(self);
         for i in 0..self_arc.n_workers {
@@ -41,7 +59,10 @@ impl Prover {
             });
         }
 
-        while provers.join_next().await.is_some() {}
+        tokio::select! {
+            _ = health_check_server_task => {},
+            _ = async { while provers.join_next().await.is_some() {} } => {},
+        }
     }
 
     #[instrument(skip(self))]