Merge pull request 'Report available disk space in `garage stats`' (#487) from report-disk-usage into main

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/487

4 files changed, 131 insertions, 22 deletions

diff --git a/src/rpc/Cargo.toml b/src/rpc/Cargo.toml
index 22b15679..87ae15ac 100644
--- a/src/rpc/Cargo.toml
+++ b/src/rpc/Cargo.toml
@@ -23,6 +23,7 @@ hex = "0.4"
 tracing = "0.1"
 rand = "0.8"
 sodiumoxide = { version = "0.2.5-0", package = "kuska-sodiumoxide" }
+systemstat = "0.2.3"
 
 async-trait = "0.1.7"
 serde = { version = "1.0", default-features = false, features = ["derive", "rc"] }
diff --git a/src/rpc/lib.rs b/src/rpc/lib.rs
index a8cc0030..5aec92c0 100644
--- a/src/rpc/lib.rs
+++ b/src/rpc/lib.rs
@@ -3,6 +3,9 @@
 #[macro_use]
 extern crate tracing;
 
+mod metrics;
+mod system_metrics;
+
 #[cfg(feature = "consul-discovery")]
 mod consul;
 #[cfg(feature = "kubernetes-discovery")]
@@ -13,9 +16,6 @@ pub mod replication_mode;
 pub mod ring;
 pub mod system;
 
-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 90f6a4c2..e0ced8cc 100644
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use std::io::{Read, Write};
 use std::net::{IpAddr, SocketAddr};
 use std::path::{Path, PathBuf};
+use std::sync::atomic::Ordering;
 use std::sync::{Arc, RwLock};
 use std::time::{Duration, Instant};
 
@@ -38,7 +39,6 @@ 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);
@@ -106,7 +106,7 @@ pub struct System {
 	consul_discovery: Option<ConsulDiscovery>,
 	#[cfg(feature = "kubernetes-discovery")]
 	kubernetes_discovery: Option<KubernetesDiscoveryConfig>,
-	#[cfg(feature = "metrics")]
+
 	metrics: SystemMetrics,
 
 	replication_mode: ReplicationMode,
@@ -118,18 +118,28 @@ pub struct System {
 
 	/// Path to metadata directory
 	pub metadata_dir: PathBuf,
+	/// Path to data directory
+	pub data_dir: PathBuf,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct NodeStatus {
 	/// Hostname of the node
 	pub hostname: String,
+
 	/// Replication factor configured on the node
 	pub replication_factor: usize,
 	/// Cluster layout version
 	pub cluster_layout_version: u64,
 	/// Hash of cluster layout staging data
 	pub cluster_layout_staging_hash: Hash,
+
+	/// Disk usage on partition containing metadata directory (tuple: `(avail, total)`)
+	#[serde(default)]
+	pub meta_disk_avail: Option<(u64, u64)>,
+	/// Disk usage on partition containing data directory (tuple: `(avail, total)`)
+	#[serde(default)]
+	pub data_disk_avail: Option<(u64, u64)>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -271,18 +281,11 @@ impl System {
 			}
 		};
 
-		let local_status = NodeStatus {
-			hostname: gethostname::gethostname()
-				.into_string()
-				.unwrap_or_else(|_| "<invalid utf-8>".to_string()),
-			replication_factor,
-			cluster_layout_version: cluster_layout.version,
-			cluster_layout_staging_hash: cluster_layout.staging_hash,
-		};
-
-		#[cfg(feature = "metrics")]
 		let metrics = SystemMetrics::new(replication_factor);
 
+		let mut local_status = NodeStatus::initial(replication_factor, &cluster_layout);
+		local_status.update_disk_usage(&config.metadata_dir, &config.data_dir, &metrics);
+
 		let ring = Ring::new(cluster_layout, replication_factor);
 		let (update_ring, ring) = watch::channel(Arc::new(ring));
 
@@ -373,12 +376,12 @@ 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),
 			metadata_dir: config.metadata_dir.clone(),
+			data_dir: config.data_dir.clone(),
 		});
 		sys.system_endpoint.set_handler(sys.clone());
 		Ok(sys)
@@ -416,12 +419,7 @@ impl System {
 					.get(&n.id.into())
 					.cloned()
 					.map(|(_, st)| st)
-					.unwrap_or(NodeStatus {
-						hostname: "?".to_string(),
-						replication_factor: 0,
-						cluster_layout_version: 0,
-						cluster_layout_staging_hash: Hash::from([0u8; 32]),
-					}),
+					.unwrap_or(NodeStatus::unknown()),
 			})
 			.collect::<Vec<_>>();
 		known_nodes
@@ -600,6 +598,9 @@ impl System {
 		let ring = self.ring.borrow();
 		new_si.cluster_layout_version = ring.layout.version;
 		new_si.cluster_layout_staging_hash = ring.layout.staging_hash;
+
+		new_si.update_disk_usage(&self.metadata_dir, &self.data_dir, &self.metrics);
+
 		self.local_status.swap(Arc::new(new_si));
 	}
 
@@ -864,6 +865,69 @@ impl EndpointHandler<SystemRpc> for System {
 	}
 }
 
+impl NodeStatus {
+	fn initial(replication_factor: usize, layout: &ClusterLayout) -> Self {
+		NodeStatus {
+			hostname: gethostname::gethostname()
+				.into_string()
+				.unwrap_or_else(|_| "<invalid utf-8>".to_string()),
+			replication_factor,
+			cluster_layout_version: layout.version,
+			cluster_layout_staging_hash: layout.staging_hash,
+			meta_disk_avail: None,
+			data_disk_avail: None,
+		}
+	}
+
+	fn unknown() -> Self {
+		NodeStatus {
+			hostname: "?".to_string(),
+			replication_factor: 0,
+			cluster_layout_version: 0,
+			cluster_layout_staging_hash: Hash::from([0u8; 32]),
+			meta_disk_avail: None,
+			data_disk_avail: None,
+		}
+	}
+
+	fn update_disk_usage(&mut self, meta_dir: &Path, data_dir: &Path, metrics: &SystemMetrics) {
+		use systemstat::{Platform, System};
+		let mounts = System::new().mounts().unwrap_or_default();
+
+		let mount_avail = |path: &Path| {
+			mounts
+				.iter()
+				.filter(|x| path.starts_with(&x.fs_mounted_on))
+				.max_by_key(|x| x.fs_mounted_on.len())
+				.map(|x| (x.avail.as_u64(), x.total.as_u64()))
+		};
+
+		self.meta_disk_avail = mount_avail(meta_dir);
+		self.data_disk_avail = mount_avail(data_dir);
+
+		if let Some((avail, total)) = self.meta_disk_avail {
+			metrics
+				.values
+				.meta_disk_avail
+				.store(avail, Ordering::Relaxed);
+			metrics
+				.values
+				.meta_disk_total
+				.store(total, Ordering::Relaxed);
+		}
+		if let Some((avail, total)) = self.data_disk_avail {
+			metrics
+				.values
+				.data_disk_avail
+				.store(avail, Ordering::Relaxed);
+			metrics
+				.values
+				.data_disk_total
+				.store(total, Ordering::Relaxed);
+		}
+	}
+}
+
 fn get_default_ip() -> Option<IpAddr> {
 	pnet_datalink::interfaces()
 		.iter()
diff --git a/src/rpc/system_metrics.rs b/src/rpc/system_metrics.rs
index d96b67e4..83f5fa97 100644
--- a/src/rpc/system_metrics.rs
+++ b/src/rpc/system_metrics.rs
@@ -1,14 +1,31 @@
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Arc;
+
 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>,
+	pub(crate) _disk_avail: ValueObserver<u64>,
+	pub(crate) _disk_total: ValueObserver<u64>,
+	pub(crate) values: Arc<SystemMetricsValues>,
+}
+
+#[derive(Default)]
+pub struct SystemMetricsValues {
+	pub(crate) data_disk_total: AtomicU64,
+	pub(crate) data_disk_avail: AtomicU64,
+	pub(crate) meta_disk_total: AtomicU64,
+	pub(crate) meta_disk_avail: AtomicU64,
 }
 
 impl SystemMetrics {
 	pub fn new(replication_factor: usize) -> Self {
 		let meter = global::meter("garage_system");
+		let values = Arc::new(SystemMetricsValues::default());
+		let values1 = values.clone();
+		let values2 = values.clone();
 		Self {
 			_garage_build_info: meter
 				.u64_value_observer("garage_build_info", move |observer| {
@@ -28,6 +45,33 @@ impl SystemMetrics {
 				})
 				.with_description("Garage replication factor setting")
 				.init(),
+			_disk_avail: meter
+				.u64_value_observer("garage_local_disk_avail", move |observer| {
+					match values1.data_disk_avail.load(Ordering::Relaxed) {
+						0 => (),
+						x => observer.observe(x, &[KeyValue::new("volume", "data")]),
+					};
+					match values1.meta_disk_avail.load(Ordering::Relaxed) {
+						0 => (),
+						x => observer.observe(x, &[KeyValue::new("volume", "metadata")]),
+					};
+				})
+				.with_description("Garage available disk space on each node")
+				.init(),
+			_disk_total: meter
+				.u64_value_observer("garage_local_disk_total", move |observer| {
+					match values2.data_disk_total.load(Ordering::Relaxed) {
+						0 => (),
+						x => observer.observe(x, &[KeyValue::new("volume", "data")]),
+					};
+					match values2.meta_disk_total.load(Ordering::Relaxed) {
+						0 => (),
+						x => observer.observe(x, &[KeyValue::new("volume", "metadata")]),
+					};
+				})
+				.with_description("Garage total disk space on each node")
+				.init(),
+			values,
 		}
 	}
 }