feat(sequencer): add possibility to disable metrics

lez/sequencer/core/src/config.rs

@@ -66,7 +66,7 @@ pub struct SequencerConfig {
     pub cross_zone: Option<CrossZoneConfig>,
     /// Address the Prometheus metrics exporter binds to.
     #[serde(default = "default_metrics_address")]
-    pub metrics_address: SocketAddr,
+    pub metrics_address: Option<SocketAddr>,
 }
 
 #[derive(Clone, Serialize, Deserialize)]
@@ -97,6 +97,7 @@ const fn default_max_block_size() -> ByteSize {
     ByteSize::mib(1)
 }
 
-const fn default_metrics_address() -> SocketAddr {
-    SequencerConfig::DEFAULT_METRICS_ADDRESS
+#[expect(clippy::unnecessary_wraps, reason = "Required by serde")]
+const fn default_metrics_address() -> Option<SocketAddr> {
+    Some(SequencerConfig::DEFAULT_METRICS_ADDRESS)
 }

lez/sequencer/core/src/tests.rs

@@ -90,7 +90,7 @@ fn setup_sequencer_config() -> SequencerConfig {
         retry_pending_blocks_timeout: Duration::from_mins(4),
         genesis: vec![],
         cross_zone: None,
-        metrics_address: SequencerConfig::DEFAULT_METRICS_ADDRESS,
+        metrics_address: None,
     }
 }
 

lez/sequencer/service/src/main.rs

@@ -39,27 +39,18 @@ struct Args {
 async fn main() -> Result<()> {
     env_logger::init();
 
-    let Args {
-        config_path,
-        port,
-        listen_address,
-        home,
-        metrics_address,
-    } = Args::parse();
+    let args = Args::parse();
 
     let cancellation_token = listen_for_shutdown_signal();
 
-    let mut config = sequencer_service::SequencerConfig::from_path(&config_path)?;
-    if let Some(home) = home {
-        config.home = home;
-    }
-    if let Some(metrics_address) = metrics_address {
-        config.metrics_address = metrics_address;
-    }
+    let mut config = sequencer_service::SequencerConfig::from_path(&args.config_path)?;
+    apply_config_overrides(&args, &mut config);
 
-    install_prometheus_recorder(config.metrics_address)?;
+    if let Some(metrics_address) = config.metrics_address {
+        install_prometheus_recorder(metrics_address)?;
+    }
     let mut sequencer_handle =
-        sequencer_service::run(config, SocketAddr::new(listen_address, port)).await?;
+        sequencer_service::run(config, SocketAddr::new(args.listen_address, args.port)).await?;
 
     tokio::select! {
         () = cancellation_token.cancelled() => {
@@ -82,6 +73,23 @@ async fn main() -> Result<()> {
     Ok(())
 }
 
+fn apply_config_overrides(args: &Args, config: &mut sequencer_service::SequencerConfig) {
+    let Args {
+        home,
+        metrics_address,
+        config_path: _,
+        port: _,
+        listen_address: _,
+    } = args;
+
+    if let Some(home) = home {
+        config.home.clone_from(home);
+    }
+    if let Some(metrics_address) = metrics_address {
+        config.metrics_address = Some(*metrics_address);
+    }
+}
+
 /// Installs the recorder on `metrics_address`.
 fn install_prometheus_recorder(metrics_address: SocketAddr) -> Result<()> {
     /// Ladder for `*_seconds` histograms, densest across the 1–100 ms band where

test_fixtures/src/config.rs

@@ -110,7 +110,7 @@ pub fn sequencer_config(
             auth: None,
         },
         cross_zone,
-        metrics_address: SequencerConfig::DEFAULT_METRICS_ADDRESS,
+        metrics_address: Some(SequencerConfig::DEFAULT_METRICS_ADDRESS),
     })
 }