Merge pull request 'Implemented system metrics' (#472) from jpds/garage:system-metrics into main

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/472
Reviewed-by: Alex <alex@adnab.me>

3 files changed, 45 insertions, 0 deletions

diff --git a/src/rpc/lib.rs b/src/rpc/lib.rs
index 86f63568..a8cc0030 100644
--- a/src/rpc/lib.rs
+++ b/src/rpc/lib.rs
@@ -17,3 +17,5 @@ mod metrics;
 pub mod rpc_helper;
 
 pub use rpc_helper::*;
+
+pub mod system_metrics;
diff --git a/src/rpc/system.rs b/src/rpc/system.rs
index ed10aa4b..90f6a4c2 100644
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@@ -38,6 +38,9 @@ use crate::replication_mode::*;
 use crate::ring::*;
 use crate::rpc_helper::*;
 
+#[cfg(feature = "metrics")]
+use crate::system_metrics::*;
+
 const DISCOVERY_INTERVAL: Duration = Duration::from_secs(60);
 const STATUS_EXCHANGE_INTERVAL: Duration = Duration::from_secs(10);
 
@@ -103,6 +106,8 @@ pub struct System {
 	consul_discovery: Option<ConsulDiscovery>,
 	#[cfg(feature = "kubernetes-discovery")]
 	kubernetes_discovery: Option<KubernetesDiscoveryConfig>,
+	#[cfg(feature = "metrics")]
+	metrics: SystemMetrics,
 
 	replication_mode: ReplicationMode,
 	replication_factor: usize,
@@ -275,6 +280,9 @@ impl System {
 			cluster_layout_staging_hash: cluster_layout.staging_hash,
 		};
 
+		#[cfg(feature = "metrics")]
+		let metrics = SystemMetrics::new(replication_factor);
+
 		let ring = Ring::new(cluster_layout, replication_factor);
 		let (update_ring, ring) = watch::channel(Arc::new(ring));
 
@@ -365,6 +373,8 @@ impl System {
 			consul_discovery,
 			#[cfg(feature = "kubernetes-discovery")]
 			kubernetes_discovery: config.kubernetes_discovery.clone(),
+			#[cfg(feature = "metrics")]
+			metrics,
 
 			ring,
 			update_ring: Mutex::new(update_ring),
diff --git a/src/rpc/system_metrics.rs b/src/rpc/system_metrics.rs
new file mode 100644
index 00000000..d96b67e4
--- /dev/null
+++ b/src/rpc/system_metrics.rs
@@ -0,0 +1,33 @@
+use opentelemetry::{global, metrics::*, KeyValue};
+
+/// TableMetrics reference all counter used for metrics
+pub struct SystemMetrics {
+	pub(crate) _garage_build_info: ValueObserver<u64>,
+	pub(crate) _replication_factor: ValueObserver<u64>,
+}
+
+impl SystemMetrics {
+	pub fn new(replication_factor: usize) -> Self {
+		let meter = global::meter("garage_system");
+		Self {
+			_garage_build_info: meter
+				.u64_value_observer("garage_build_info", move |observer| {
+					observer.observe(
+						1,
+						&[KeyValue::new(
+							"version",
+							garage_util::version::garage_version(),
+						)],
+					)
+				})
+				.with_description("Garage build info")
+				.init(),
+			_replication_factor: meter
+				.u64_value_observer("garage_replication_factor", move |observer| {
+					observer.observe(replication_factor as u64, &[])
+				})
+				.with_description("Garage replication factor setting")
+				.init(),
+		}
+	}
+}