Merge branch 'dev-0.2'

4 files changed, 128 insertions, 0 deletions

diff --git a/src/table/replication/fullcopy.rs b/src/table/replication/fullcopy.rs
new file mode 100644
index 00000000..bd658f63
--- /dev/null
+++ b/src/table/replication/fullcopy.rs
@@ -0,0 +1,51 @@
+use std::sync::Arc;
+
+use garage_rpc::membership::System;
+use garage_rpc::ring::*;
+use garage_util::data::*;
+
+use crate::replication::*;
+
+#[derive(Clone)]
+pub struct TableFullReplication {
+	pub system: Arc<System>,
+	pub max_faults: usize,
+}
+
+impl TableReplication for TableFullReplication {
+	// Full replication schema: all nodes store everything
+	// Writes are disseminated in an epidemic manner in the network
+
+	// Advantage: do all reads locally, extremely fast
+	// Inconvenient: only suitable to reasonably small tables
+
+	fn read_nodes(&self, _hash: &Hash) -> Vec<UUID> {
+		vec![self.system.id]
+	}
+	fn read_quorum(&self) -> usize {
+		1
+	}
+
+	fn write_nodes(&self, _hash: &Hash) -> Vec<UUID> {
+		let ring = self.system.ring.borrow();
+		ring.config.members.keys().cloned().collect::<Vec<_>>()
+	}
+	fn write_quorum(&self) -> usize {
+		let nmembers = self.system.ring.borrow().config.members.len();
+		if nmembers > self.max_faults {
+			nmembers - self.max_faults
+		} else {
+			1
+		}
+	}
+	fn max_write_errors(&self) -> usize {
+		self.max_faults
+	}
+
+	fn partition_of(&self, _hash: &Hash) -> Partition {
+		0u16
+	}
+	fn partitions(&self) -> Vec<(Partition, Hash)> {
+		vec![(0u16, [0u8; 32].into())]
+	}
+}
diff --git a/src/table/replication/mod.rs b/src/table/replication/mod.rs
new file mode 100644
index 00000000..d43d7f19
--- /dev/null
+++ b/src/table/replication/mod.rs
@@ -0,0 +1,6 @@
+mod parameters;
+
+pub mod fullcopy;
+pub mod sharded;
+
+pub use parameters::*;
diff --git a/src/table/replication/parameters.rs b/src/table/replication/parameters.rs
new file mode 100644
index 00000000..e46bd172
--- /dev/null
+++ b/src/table/replication/parameters.rs
@@ -0,0 +1,21 @@
+use garage_rpc::ring::*;
+
+use garage_util::data::*;
+
+pub trait TableReplication: Send + Sync {
+	// See examples in table_sharded.rs and table_fullcopy.rs
+	// To understand various replication methods
+
+	// Which nodes to send reads from
+	fn read_nodes(&self, hash: &Hash) -> Vec<UUID>;
+	fn read_quorum(&self) -> usize;
+
+	// Which nodes to send writes to
+	fn write_nodes(&self, hash: &Hash) -> Vec<UUID>;
+	fn write_quorum(&self) -> usize;
+	fn max_write_errors(&self) -> usize;
+
+	// Accessing partitions, for Merkle tree & sync
+	fn partition_of(&self, hash: &Hash) -> Partition;
+	fn partitions(&self) -> Vec<(Partition, Hash)>;
+}
diff --git a/src/table/replication/sharded.rs b/src/table/replication/sharded.rs
new file mode 100644
index 00000000..dce74b03
--- /dev/null
+++ b/src/table/replication/sharded.rs
@@ -0,0 +1,50 @@
+use std::sync::Arc;
+
+use garage_rpc::membership::System;
+use garage_rpc::ring::*;
+use garage_util::data::*;
+
+use crate::replication::*;
+
+#[derive(Clone)]
+pub struct TableShardedReplication {
+	pub system: Arc<System>,
+	pub replication_factor: usize,
+	pub read_quorum: usize,
+	pub write_quorum: usize,
+}
+
+impl TableReplication for TableShardedReplication {
+	// Sharded replication schema:
+	// - based on the ring of nodes, a certain set of neighbors
+	//   store entries, given as a function of the position of the
+	//   entry's hash in the ring
+	// - reads are done on all of the nodes that replicate the data
+	// - writes as well
+
+	fn read_nodes(&self, hash: &Hash) -> Vec<UUID> {
+		let ring = self.system.ring.borrow().clone();
+		ring.walk_ring(&hash, self.replication_factor)
+	}
+	fn read_quorum(&self) -> usize {
+		self.read_quorum
+	}
+
+	fn write_nodes(&self, hash: &Hash) -> Vec<UUID> {
+		let ring = self.system.ring.borrow();
+		ring.walk_ring(&hash, self.replication_factor)
+	}
+	fn write_quorum(&self) -> usize {
+		self.write_quorum
+	}
+	fn max_write_errors(&self) -> usize {
+		self.replication_factor - self.write_quorum
+	}
+
+	fn partition_of(&self, hash: &Hash) -> Partition {
+		self.system.ring.borrow().partition_of(hash)
+	}
+	fn partitions(&self) -> Vec<(Partition, Hash)> {
+		self.system.ring.borrow().partitions()
+	}
+}