feat: Add support for health check endpoint (#410)

Cargo.toml

@@ -18,7 +18,6 @@ zksync_utils = { git = "https://github.com/matter-labs/zksync-era.git", rev = "6
 zksync_web3_decl = { git = "https://github.com/matter-labs/zksync-era.git", rev = "6c034f6e180cc92e99766f14c8840c90efa56cec", features = [
     "server",
 ] }
-sha3 = "0.10.6"
 
 # alloy
 alloy-signer-local = { version = "0.5.4", features = ["mnemonic"] }
@@ -59,7 +58,6 @@ rustc-hash = "1.1.0"
 indexmap = "2.0.1"
 chrono = { version = "0.4.31", default-features = false }
 time = "0.3.36"
-toml = "0.8.13"
 rand = "0.8"
 
 [dev-dependencies]

src/config/cli.rs

@@ -31,6 +31,12 @@ pub struct Cli {
     /// Run in offline mode (disables all network requests).
     pub offline: bool,
 
+    #[arg(long, help_heading = "General Options")]
+    /// Enable health check endpoint.
+    /// It will be available for GET requests at /health.
+    /// The endpoint will return 200 OK if the node is healthy.
+    pub health_check_endpoint: bool,
+
     /// Writes output of `era-test-node` as json to user-specified file.
     #[arg(long, value_name = "OUT_FILE", help_heading = "General Options")]
     pub config_out: Option<String>,
@@ -293,7 +299,12 @@ impl Cli {
             }))
             .with_chain_id(self.chain_id)
             .set_config_out(self.config_out)
-            .with_evm_emulator(if self.emulate_evm { Some(true) } else { None });
+            .with_evm_emulator(if self.emulate_evm { Some(true) } else { None })
+            .with_health_check_endpoint(if self.health_check_endpoint {
+                Some(true)
+            } else {
+                None
+            });
 
         if self.emulate_evm && self.dev_system_contracts != Some(SystemContractsOptions::Local) {
             return Err(eyre::eyre!(

src/config/mod.rs

@@ -99,6 +99,8 @@ pub struct TestNodeConfig {
     pub signer_accounts: Vec<PrivateKeySigner>,
     /// Whether the node operates in offline mode
     pub offline: bool,
+    /// Whether we need to enable the health check endpoint.
+    pub health_check_endpoint: bool,
 }
 
 impl Default for TestNodeConfig {
@@ -143,6 +145,7 @@ impl Default for TestNodeConfig {
 
             // Offline mode disabled by default
             offline: false,
+            health_check_endpoint: false,
         }
     }
 }
@@ -287,6 +290,14 @@ impl TestNodeConfig {
                 "Disabled".red()
             }
         );
+        tracing::info!(
+            "Health Check Endpoint: {}",
+            if self.health_check_endpoint {
+                "Enabled".green()
+            } else {
+                "Disabled".red()
+            }
+        );
         println!("\n");
         tracing::info!("========================================");
         tracing::info!(
@@ -623,6 +634,20 @@ impl TestNodeConfig {
     pub fn is_offline(&self) -> bool {
         self.offline
     }
+
+    /// Set the health check endpoint mode
+    #[must_use]
+    pub fn with_health_check_endpoint(mut self, health_check_endpoint: Option<bool>) -> Self {
+        if let Some(health_check_endpoint) = health_check_endpoint {
+            self.health_check_endpoint = health_check_endpoint;
+        }
+        self
+    }
+
+    /// Get the health check endpoint mode status
+    pub fn is_health_check_endpoint_endpoint_enabled(&self) -> bool {
+        self.health_check_endpoint
+    }
 }
 
 /// Account Generator

src/main.rs

@@ -62,6 +62,7 @@ async fn build_json_http<
     addr: SocketAddr,
     log_level_filter: LevelFilter,
     node: InMemoryNode<S>,
+    enable_health_api: bool,
 ) -> tokio::task::JoinHandle<()> {
     let (sender, recv) = oneshot::channel::<()>();
 
@@ -88,11 +89,15 @@ async fn build_json_http<
             .build()
             .unwrap();
 
-        let server = jsonrpc_http_server::ServerBuilder::new(io_handler)
+        let mut builder = jsonrpc_http_server::ServerBuilder::new(io_handler)
             .threads(1)
-            .event_loop_executor(runtime.handle().clone())
-            .start_http(&addr)
-            .unwrap();
+            .event_loop_executor(runtime.handle().clone());
+
+        if enable_health_api {
+            builder = builder.health_api(("/health", "web3_clientVersion"));
+        }
+
+        let server = builder.start_http(&addr).unwrap();
 
         server.wait();
         let _ = sender;
@@ -293,6 +298,7 @@ async fn main() -> anyhow::Result<()> {
         SocketAddr::new(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)), config.port),
         log_level_filter,
         node,
+        config.health_check_endpoint,
     )
     .await;