4 files changed, 95 insertions, 5 deletions
diff --git a/src/rpc/Cargo.toml b/src/rpc/Cargo.toml
index f06606e5..57b61a08 100644
--- a/src/rpc/Cargo.toml
+++ b/src/rpc/Cargo.toml
@@ -43,8 +43,9 @@ futures = "0.3"
 futures-util = "0.3"
 tokio = { version = "1.0", default-features = false, features = ["rt", "rt-multi-thread", "io-util", "net", "time", "macros", "sync", "signal", "fs"] }
 tokio-stream = { version = "0.1", features = ["net"] }
+opentelemetry = "0.17"
 
 #netapp = { version = "0.3.0", git = "https://git.deuxfleurs.fr/lx/netapp" }
-netapp = "0.3.0"
+netapp = "0.3.1"
 hyper = { version = "0.14", features = ["client", "http1", "runtime", "tcp"] }
 
diff --git a/src/rpc/lib.rs b/src/rpc/lib.rs
index 2c877a7f..736513f4 100644
--- a/src/rpc/lib.rs
+++ b/src/rpc/lib.rs
@@ -10,6 +10,7 @@ pub mod layout;
 pub mod ring;
 pub mod system;
 
+mod metrics;
 pub mod rpc_helper;
 
 pub use rpc_helper::*;
diff --git a/src/rpc/metrics.rs b/src/rpc/metrics.rs
new file mode 100644
index 00000000..c900518c
--- /dev/null
+++ b/src/rpc/metrics.rs
@@ -0,0 +1,55 @@
+use std::sync::Arc;
+
+use opentelemetry::{global, metrics::*};
+use tokio::sync::Semaphore;
+
+/// TableMetrics reference all counter used for metrics
+pub struct RpcMetrics {
+	pub(crate) _rpc_available_permits: ValueObserver<u64>,
+
+	pub(crate) rpc_counter: Counter<u64>,
+	pub(crate) rpc_timeout_counter: Counter<u64>,
+	pub(crate) rpc_netapp_error_counter: Counter<u64>,
+	pub(crate) rpc_garage_error_counter: Counter<u64>,
+
+	pub(crate) rpc_duration: ValueRecorder<f64>,
+	pub(crate) rpc_queueing_time: ValueRecorder<f64>,
+}
+impl RpcMetrics {
+	pub fn new(sem: Arc<Semaphore>) -> Self {
+		let meter = global::meter("garage_rpc");
+		RpcMetrics {
+			_rpc_available_permits: meter
+				.u64_value_observer("rpc.available_permits", move |observer| {
+					observer.observe(sem.available_permits() as u64, &[])
+				})
+				.with_description("Number of available RPC permits")
+				.init(),
+
+			rpc_counter: meter
+				.u64_counter("rpc.request_counter")
+				.with_description("Number of RPC requests emitted")
+				.init(),
+			rpc_timeout_counter: meter
+				.u64_counter("rpc.timeout_counter")
+				.with_description("Number of RPC timeouts")
+				.init(),
+			rpc_netapp_error_counter: meter
+				.u64_counter("rpc.netapp_error_counter")
+				.with_description("Number of communication errors (errors in the Netapp library)")
+				.init(),
+			rpc_garage_error_counter: meter
+				.u64_counter("rpc.garage_error_counter")
+				.with_description("Number of RPC errors (errors happening when handling the RPC)")
+				.init(),
+			rpc_duration: meter
+				.f64_value_recorder("rpc.duration")
+				.with_description("Duration of RPCs")
+				.init(),
+			rpc_queueing_time: meter
+				.f64_value_recorder("rpc.queueing_time")
+				.with_description("Time RPC requests were queued for before being sent")
+				.init(),
+		}
+	}
+}
diff --git a/src/rpc/rpc_helper.rs b/src/rpc/rpc_helper.rs
index 68bdfc4f..0d722e43 100644
--- a/src/rpc/rpc_helper.rs
+++ b/src/rpc/rpc_helper.rs
@@ -1,11 +1,12 @@
 //! Contain structs related to making RPCs
 use std::sync::Arc;
-use std::time::Duration;
+use std::time::{Duration, SystemTime};
 
 use futures::future::join_all;
 use futures::stream::futures_unordered::FuturesUnordered;
 use futures::stream::StreamExt;
 use futures_util::future::FutureExt;
+use opentelemetry::KeyValue;
 use tokio::select;
 use tokio::sync::{watch, Semaphore};
 
@@ -18,6 +19,7 @@ use garage_util::background::BackgroundRunner;
 use garage_util::data::*;
 use garage_util::error::Error;
 
+use crate::metrics::RpcMetrics;
 use crate::ring::Ring;
 
 const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
@@ -76,7 +78,8 @@ struct RpcHelperInner {
 	fullmesh: Arc<FullMeshPeeringStrategy>,
 	background: Arc<BackgroundRunner>,
 	ring: watch::Receiver<Arc<Ring>>,
-	request_buffer_semaphore: Semaphore,
+	request_buffer_semaphore: Arc<Semaphore>,
+	metrics: RpcMetrics,
 }
 
 impl RpcHelper {
@@ -86,12 +89,17 @@ impl RpcHelper {
 		background: Arc<BackgroundRunner>,
 		ring: watch::Receiver<Arc<Ring>>,
 	) -> Self {
+		let sem = Arc::new(Semaphore::new(REQUEST_BUFFER_SIZE));
+
+		let metrics = RpcMetrics::new(sem.clone());
+
 		Self(Arc::new(RpcHelperInner {
 			our_node_id,
 			fullmesh,
 			background,
 			ring,
-			request_buffer_semaphore: Semaphore::new(REQUEST_BUFFER_SIZE),
+			request_buffer_semaphore: sem,
+			metrics,
 		}))
 	}
 
@@ -120,6 +128,9 @@ impl RpcHelper {
 		M: Rpc<Response = Result<S, Error>>,
 		H: EndpointHandler<M>,
 	{
+		let queueing_start_time = SystemTime::now();
+		let metric_tags = [KeyValue::new("endpoint", endpoint.path().to_string())];
+
 		let msg_size = rmp_to_vec_all_named(&msg)?.len() as u32;
 		let permit = self
 			.0
@@ -127,14 +138,36 @@ impl RpcHelper {
 			.acquire_many(msg_size)
 			.await?;
 
+		self.0.metrics.rpc_queueing_time.record(
+			queueing_start_time
+				.elapsed()
+				.map_or(0.0, |d| d.as_secs_f64()),
+			&metric_tags,
+		);
+		self.0.metrics.rpc_counter.add(1, &metric_tags);
+		let rpc_start_time = SystemTime::now();
+
 		let node_id = to.into();
 		select! {
 			res = endpoint.call(&node_id, &msg, strat.rs_priority) => {
 				drop(permit);
-				Ok(res??)
+
+				if res.is_err() {
+					self.0.metrics.rpc_netapp_error_counter.add(1, &metric_tags);
+				}
+				let res = res?;
+
+				self.0.metrics.rpc_duration
+			.record(rpc_start_time.elapsed().map_or(0.0, |d| d.as_secs_f64()), &metric_tags);
+				if res.is_err() {
+					self.0.metrics.rpc_garage_error_counter.add(1, &metric_tags);
+				}
+
+				Ok(res?)
 			}
 			_ = tokio::time::sleep(strat.rs_timeout) => {
 				drop(permit);
+				self.0.metrics.rpc_timeout_counter.add(1, &metric_tags);
 				Err(Error::Timeout)
 			}
 		}