cli: config --p2p-relay-loglevel into tracing filter

crates/cli/Cargo.toml

@@ -49,6 +49,7 @@ sha2.workspace = true
 
 [dev-dependencies]
 tempfile.workspace = true
+tracing-subscriber.workspace = true
 test-case.workspace = true
 backon.workspace = true
 wiremock.workspace = true

crates/cli/src/commands/relay.rs

@@ -12,6 +12,16 @@ use tracing::{error, info};
 /// once `BackgroundTaskController::shutdown` has been signalled.
 const LOKI_FLUSH_TIMEOUT: Duration = Duration::from_secs(3);
 
+/// Adds a `libp2p_relay` directive to the `base` env filter, which `EnvFilter`
+/// prefix-matches against every `libp2p_relay::*` target.
+fn relay_filter(base: &str, relay_level: &str) -> String {
+    if relay_level.is_empty() {
+        base.to_string()
+    } else {
+        format!("{base},libp2p_relay={relay_level}")
+    }
+}
+
 /// Arguments for the relay command.
 #[derive(clap::Args, Clone)]
 pub struct RelayArgs {
@@ -90,14 +100,16 @@ impl TryInto<pluto_relay_server::config::Config> for RelayArgs {
             }
         };
 
-        let log_config =
-            build_console_tracing_config(self.log.level.clone(), &self.log.color, loki_config);
+        let log_config = build_console_tracing_config(
+            relay_filter(&self.log.level, &self.relay.p2p_relay_log_level),
+            &self.log.color,
+            loki_config,
+        );
 
         let builder = pluto_relay_server::config::Config::builder()
             .data_dir(self.data_dir.data_dir)
             .http_addr(self.relay.http_address)
             .auto_p2p_key(self.relay.auto_p2p_key)
-            .libp2p_log_level(self.relay.p2p_relay_log_level)
             .max_res_per_peer(self.relay.max_res_per_peer)
             .max_conns(self.relay.max_conns)
             // Invert p2p-advertise-private-addresses flag boolean:
@@ -381,6 +393,8 @@ mod tests {
     use std::{str::FromStr, time};
     use tokio::net;
     use tokio_util::sync::CancellationToken;
+    use tracing::{Level, enabled};
+    use tracing_subscriber::{EnvFilter, layer::SubscriberExt as _};
 
     #[tokio::test]
     async fn run_bootnode() {
@@ -640,4 +654,24 @@ mod tests {
             .build();
         request.retry(&mut backoff).await
     }
+
+    /// Runs `f` with a subscriber that only lets `filter` through.
+    fn with_filter(filter: &str, f: impl FnOnce()) {
+        let filter = EnvFilter::from_str(filter).expect("relay filter should be a valid EnvFilter");
+        tracing::subscriber::with_default(tracing_subscriber::registry().with(filter), f);
+    }
+
+    #[test]
+    fn relay_filter_scopes_upstream_relay_logs() {
+        // An empty relay level leaves the base filter alone.
+        with_filter(&super::relay_filter("info", ""), || {
+            assert!(enabled!(target: "libp2p_relay::behaviour::handler", Level::WARN));
+        });
+
+        // A relay level silences the upstream relay crate but not our own logs.
+        with_filter(&super::relay_filter("info", "error"), || {
+            assert!(!enabled!(target: "libp2p_relay::behaviour::handler", Level::WARN));
+            assert!(enabled!(target: "pluto_relay_server::p2p", Level::INFO));
+        });
+    }
 }

crates/relay-server/src/config.rs

@@ -49,9 +49,6 @@ pub struct Config {
     /// Whether to filter private addresses.
     #[builder(default = false)]
     pub filter_private_addrs: bool,
-    /// LibP2PLogLevel.
-    #[builder(default = "Info".to_string())]
-    pub libp2p_log_level: String,
 }
 
 pub(crate) fn create_relay_config(config: &Config) -> relay::Config {