src/rpc/layout/history.rs

@@ -18,7 +18,7 @@ impl LayoutHistory {
 		};
 
 		let mut ret = LayoutHistory {
-			versions: vec![version].into_boxed_slice().into(),
+			versions: vec![version],
 			update_trackers: Default::default(),
 			trackers_hash: [0u8; 32].into(),
 			staging: Lww::raw(0, staging),
@@ -211,6 +211,11 @@ To know the correct value of the new layout version, invoke `garage layout show`
 
 		let msg = new_version.calculate_partition_assignment()?;
 		self.versions.push(new_version);
+		if self.current().check().is_ok() {
+			while self.versions.first().unwrap().check().is_err() {
+				self.versions.remove(0);
+			}
+		}
 
 		// Reset the staged layout changes
 		self.staging.update(LayoutStaging {
@@ -245,7 +250,7 @@ To know the correct value of the new layout version, invoke `garage layout show`
 			version.check()?;
 		}
 
-		// TODO: anythign more ?
+		// TODO: anything more ?
 		Ok(())
 	}
 }

src/rpc/layout/mod.rs

@@ -3,6 +3,9 @@ mod history;
 mod schema;
 mod version;
 
+#[cfg(test)]
+mod test;
+
 pub mod manager;
 
 // ---- re-exports ----

src/rpc/layout/test.rs

@@ -0,0 +1,159 @@
+use std::cmp::min;
+use std::collections::HashMap;
+
+use garage_util::crdt::Crdt;
+use garage_util::error::*;
+
+use crate::layout::*;
+
+// This function checks that the partition size S computed is at least better than the
+// one given by a very naive algorithm. To do so, we try to run the naive algorithm
+// assuming a partion size of S+1. If we succed, it means that the optimal assignment
+// was not optimal. The naive algorithm is the following :
+// - we compute the max number of partitions associated to every node, capped at the
+// partition number. It gives the number of tokens of every node.
+// - every zone has a number of tokens equal to the sum of the tokens of its nodes.
+// - we cycle over the partitions and associate zone tokens while respecting the
+// zone redundancy constraint.
+// NOTE: the naive algorithm is not optimal. Counter example:
+// take nb_partition = 3  ; replication_factor = 5; redundancy = 4;
+// number of tokens by zone : (A, 4), (B,1), (C,4), (D, 4), (E, 2)
+// With these parameters, the naive algo fails, whereas there is a solution:
+// (A,A,C,D,E) , (A,B,C,D,D) (A,C,C,D,E)
+fn check_against_naive(cl: &LayoutVersion) -> Result<bool, Error> {
+	let over_size = cl.partition_size + 1;
+	let mut zone_token = HashMap::<String, usize>::new();
+
+	let (zones, zone_to_id) = cl.generate_nongateway_zone_ids()?;
+
+	if zones.is_empty() {
+		return Ok(false);
+	}
+
+	for z in zones.iter() {
+		zone_token.insert(z.clone(), 0);
+	}
+	for uuid in cl.nongateway_nodes() {
+		let z = cl.get_node_zone(&uuid)?;
+		let c = cl.get_node_capacity(&uuid)?;
+		zone_token.insert(
+			z.to_string(),
+			zone_token[z] + min(NB_PARTITIONS, (c / over_size) as usize),
+		);
+	}
+
+	// For every partition, we count the number of zone already associated and
+	// the name of the last zone associated
+
+	let mut id_zone_token = vec![0; zones.len()];
+	for (z, t) in zone_token.iter() {
+		id_zone_token[zone_to_id[z]] = *t;
+	}
+
+	let mut nb_token = vec![0; NB_PARTITIONS];
+	let mut last_zone = vec![zones.len(); NB_PARTITIONS];
+
+	let mut curr_zone = 0;
+
+	let redundancy = cl.effective_zone_redundancy();
+
+	for replic in 0..cl.replication_factor {
+		for p in 0..NB_PARTITIONS {
+			while id_zone_token[curr_zone] == 0
+				|| (last_zone[p] == curr_zone
+					&& redundancy - nb_token[p] <= cl.replication_factor - replic)
+			{
+				curr_zone += 1;
+				if curr_zone >= zones.len() {
+					return Ok(true);
+				}
+			}
+			id_zone_token[curr_zone] -= 1;
+			if last_zone[p] != curr_zone {
+				nb_token[p] += 1;
+				last_zone[p] = curr_zone;
+			}
+		}
+	}
+
+	return Ok(false);
+}
+
+fn show_msg(msg: &Message) {
+	for s in msg.iter() {
+		println!("{}", s);
+	}
+}
+
+fn update_layout(
+	cl: &mut LayoutHistory,
+	node_capacity_vec: &[u64],
+	node_zone_vec: &[&'static str],
+	zone_redundancy: usize,
+) {
+	let staging = cl.staging.get_mut();
+
+	for (i, (capacity, zone)) in node_capacity_vec
+		.iter()
+		.zip(node_zone_vec.iter())
+		.enumerate()
+	{
+		let node_id = [i as u8; 32].into();
+
+		let update = staging.roles.update_mutator(
+			node_id,
+			NodeRoleV(Some(NodeRole {
+				zone: zone.to_string(),
+				capacity: Some(*capacity),
+				tags: (vec![]),
+			})),
+		);
+		staging.roles.merge(&update);
+	}
+	staging.parameters.update(LayoutParameters {
+		zone_redundancy: ZoneRedundancy::AtLeast(zone_redundancy),
+	});
+
+	cl.update_hashes();
+}
+
+#[test]
+fn test_assignment() {
+	let mut node_capacity_vec = vec![4000, 1000, 2000];
+	let mut node_zone_vec = vec!["A", "B", "C"];
+
+	let mut cl = LayoutHistory::new(3);
+	update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 3);
+	let v = cl.current().version;
+	let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+	show_msg(&msg);
+	assert_eq!(cl.check(), Ok(()));
+	assert!(check_against_naive(cl.current()).unwrap());
+
+	node_capacity_vec = vec![4000, 1000, 1000, 3000, 1000, 1000, 2000, 10000, 2000];
+	node_zone_vec = vec!["A", "B", "C", "C", "C", "B", "G", "H", "I"];
+	update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 2);
+	let v = cl.current().version;
+	let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+	show_msg(&msg);
+	assert_eq!(cl.check(), Ok(()));
+	assert!(check_against_naive(cl.current()).unwrap());
+
+	node_capacity_vec = vec![4000, 1000, 2000, 7000, 1000, 1000, 2000, 10000, 2000];
+	update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 3);
+	let v = cl.current().version;
+	let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+	show_msg(&msg);
+	assert_eq!(cl.check(), Ok(()));
+	assert!(check_against_naive(cl.current()).unwrap());
+
+	node_capacity_vec = vec![
+		4000000, 4000000, 2000000, 7000000, 1000000, 9000000, 2000000, 10000, 2000000,
+	];
+	update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 1);
+	let v = cl.current().version;
+	let (cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+	show_msg(&msg);
+	assert_eq!(cl.check(), Ok(()));
+	assert!(check_against_naive(cl.current()).unwrap());
+}

src/rpc/layout/version.rs

@@ -143,7 +143,7 @@ impl LayoutVersion {
 	}
 
 	/// Given a node uuids, this function returns the label of its zone
-	fn get_node_zone(&self, uuid: &Uuid) -> Result<&str, Error> {
+	pub(crate) fn get_node_zone(&self, uuid: &Uuid) -> Result<&str, Error> {
 		match self.node_role(uuid) {
 			Some(role) => Ok(&role.zone),
 			_ => Err(Error::Message(
@@ -162,7 +162,7 @@ impl LayoutVersion {
 	}
 
 	/// Returns the effective value of the zone_redundancy parameter
-	fn effective_zone_redundancy(&self) -> usize {
+	pub(crate) fn effective_zone_redundancy(&self) -> usize {
 		match self.parameters.zone_redundancy {
 			ZoneRedundancy::AtLeast(v) => v,
 			ZoneRedundancy::Maximum => {
@@ -472,7 +472,9 @@ impl LayoutVersion {
 
 	/// This function generates ids for the zone of the nodes appearing in
 	/// self.node_id_vec.
-	fn generate_nongateway_zone_ids(&self) -> Result<(Vec<String>, HashMap<String, usize>), Error> {
+	pub(crate) fn generate_nongateway_zone_ids(
+		&self,
+	) -> Result<(Vec<String>, HashMap<String, usize>), Error> {
 		let mut id_to_zone = Vec::<String>::new();
 		let mut zone_to_id = HashMap::<String, usize>::new();
 
@@ -838,167 +840,3 @@ impl LayoutVersion {
 		Ok(msg)
 	}
 }
-
-// ====================================================================================
-
-#[cfg(test)]
-mod tests {
-	use super::{Error, *};
-	use std::cmp::min;
-
-	// This function checks that the partition size S computed is at least better than the
-	// one given by a very naive algorithm. To do so, we try to run the naive algorithm
-	// assuming a partion size of S+1. If we succed, it means that the optimal assignment
-	// was not optimal. The naive algorithm is the following :
-	// - we compute the max number of partitions associated to every node, capped at the
-	// partition number. It gives the number of tokens of every node.
-	// - every zone has a number of tokens equal to the sum of the tokens of its nodes.
-	// - we cycle over the partitions and associate zone tokens while respecting the
-	// zone redundancy constraint.
-	// NOTE: the naive algorithm is not optimal. Counter example:
-	// take nb_partition = 3  ; replication_factor = 5; redundancy = 4;
-	// number of tokens by zone : (A, 4), (B,1), (C,4), (D, 4), (E, 2)
-	// With these parameters, the naive algo fails, whereas there is a solution:
-	// (A,A,C,D,E) , (A,B,C,D,D) (A,C,C,D,E)
-	fn check_against_naive(cl: &LayoutVersion) -> Result<bool, Error> {
-		let over_size = cl.partition_size + 1;
-		let mut zone_token = HashMap::<String, usize>::new();
-
-		let (zones, zone_to_id) = cl.generate_nongateway_zone_ids()?;
-
-		if zones.is_empty() {
-			return Ok(false);
-		}
-
-		for z in zones.iter() {
-			zone_token.insert(z.clone(), 0);
-		}
-		for uuid in cl.nongateway_nodes() {
-			let z = cl.get_node_zone(&uuid)?;
-			let c = cl.get_node_capacity(&uuid)?;
-			zone_token.insert(
-				z.clone(),
-				zone_token[&z] + min(NB_PARTITIONS, (c / over_size) as usize),
-			);
-		}
-
-		// For every partition, we count the number of zone already associated and
-		// the name of the last zone associated
-
-		let mut id_zone_token = vec![0; zones.len()];
-		for (z, t) in zone_token.iter() {
-			id_zone_token[zone_to_id[z]] = *t;
-		}
-
-		let mut nb_token = vec![0; NB_PARTITIONS];
-		let mut last_zone = vec![zones.len(); NB_PARTITIONS];
-
-		let mut curr_zone = 0;
-
-		let redundancy = cl.effective_zone_redundancy();
-
-		for replic in 0..cl.replication_factor {
-			for p in 0..NB_PARTITIONS {
-				while id_zone_token[curr_zone] == 0
-					|| (last_zone[p] == curr_zone
-						&& redundancy - nb_token[p] <= cl.replication_factor - replic)
-				{
-					curr_zone += 1;
-					if curr_zone >= zones.len() {
-						return Ok(true);
-					}
-				}
-				id_zone_token[curr_zone] -= 1;
-				if last_zone[p] != curr_zone {
-					nb_token[p] += 1;
-					last_zone[p] = curr_zone;
-				}
-			}
-		}
-
-		return Ok(false);
-	}
-
-	fn show_msg(msg: &Message) {
-		for s in msg.iter() {
-			println!("{}", s);
-		}
-	}
-
-	fn update_layout(
-		cl: &mut LayoutVersion,
-		node_id_vec: &Vec<u8>,
-		node_capacity_vec: &Vec<u64>,
-		node_zone_vec: &Vec<String>,
-		zone_redundancy: usize,
-	) {
-		for i in 0..node_id_vec.len() {
-			if let Some(x) = FixedBytes32::try_from(&[i as u8; 32]) {
-				cl.node_id_vec.push(x);
-			}
-
-			let update = cl.staging_roles.update_mutator(
-				cl.node_id_vec[i],
-				NodeRoleV(Some(NodeRole {
-					zone: (node_zone_vec[i].to_string()),
-					capacity: (Some(node_capacity_vec[i])),
-					tags: (vec![]),
-				})),
-			);
-			cl.staging_roles.merge(&update);
-		}
-		cl.staging_parameters.update(LayoutParameters {
-			zone_redundancy: ZoneRedundancy::AtLeast(zone_redundancy),
-		});
-		cl.staging_hash = cl.calculate_staging_hash();
-	}
-
-	#[test]
-	fn test_assignment() {
-		let mut node_id_vec = vec![1, 2, 3];
-		let mut node_capacity_vec = vec![4000, 1000, 2000];
-		let mut node_zone_vec = vec!["A", "B", "C"]
-			.into_iter()
-			.map(|x| x.to_string())
-			.collect();
-
-		let mut cl = LayoutVersion::new(3);
-		update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec, 3);
-		let v = cl.version;
-		let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
-		show_msg(&msg);
-		assert_eq!(cl.check(), Ok(()));
-		assert!(matches!(check_against_naive(&cl), Ok(true)));
-
-		node_id_vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
-		node_capacity_vec = vec![4000, 1000, 1000, 3000, 1000, 1000, 2000, 10000, 2000];
-		node_zone_vec = vec!["A", "B", "C", "C", "C", "B", "G", "H", "I"]
-			.into_iter()
-			.map(|x| x.to_string())
-			.collect();
-		update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec, 2);
-		let v = cl.version;
-		let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
-		show_msg(&msg);
-		assert_eq!(cl.check(), Ok(()));
-		assert!(matches!(check_against_naive(&cl), Ok(true)));
-
-		node_capacity_vec = vec![4000, 1000, 2000, 7000, 1000, 1000, 2000, 10000, 2000];
-		update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec, 3);
-		let v = cl.version;
-		let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
-		show_msg(&msg);
-		assert_eq!(cl.check(), Ok(()));
-		assert!(matches!(check_against_naive(&cl), Ok(true)));
-
-		node_capacity_vec = vec![
-			4000000, 4000000, 2000000, 7000000, 1000000, 9000000, 2000000, 10000, 2000000,
-		];
-		update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec, 1);
-		let v = cl.version;
-		let (cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
-		show_msg(&msg);
-		assert_eq!(cl.check(), Ok(()));
-		assert!(matches!(check_against_naive(&cl), Ok(true)));
-	}
-}