Merge pull request 'Use cleaner CRDT data types for objects to avoid accidents like #16' (#18) from feature/better-crdt into master

Reviewed-on: #18

Cargo.lock

@@ -15,6 +15,16 @@ version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4d25d88fd6b8041580a654f9d0c581a047baee2b3efee13275f2fc392fc75034"
 
+[[package]]
+name = "arrayvec"
+version = "0.3.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06f59fe10306bb78facd90d28c2038ad23ffaaefa85bac43c8a434cde383334f"
+dependencies = [
+ "nodrop",
+ "odds",
+]
+
 [[package]]
 name = "async-trait"
 version = "0.1.36"
@@ -588,6 +598,7 @@ dependencies = [
  "garage_rpc 0.1.0",
  "garage_util 0.1.0",
  "hex",
+ "hexdump",
  "log",
  "rand",
  "rmp-serde",
@@ -743,6 +754,16 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
 
+[[package]]
+name = "hexdump"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "850f3f2c33d20c0f96c4485e087dd580ff041d720988ebf4c84a42acf739262b"
+dependencies = [
+ "arrayvec",
+ "itertools",
+]
+
 [[package]]
 name = "hmac"
 version = "0.7.1"
@@ -870,6 +891,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4a9b56eb56058f43dc66e58f40a214b2ccbc9f3df51861b63d51dec7b65bc3f"
+
 [[package]]
 name = "itoa"
 version = "0.4.6"
@@ -1027,6 +1054,12 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "nodrop"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
+
 [[package]]
 name = "num-integer"
 version = "0.1.43"
@@ -1056,6 +1089,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "odds"
+version = "0.2.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eae0151b9dacf24fcc170d9995e511669a082856a91f958a2fe380bfab3fb22"
+
 [[package]]
 name = "once_cell"
 version = "1.4.0"

src/api/signature.rs

@@ -68,7 +68,7 @@ pub async fn check_signature(
 		.key_table
 		.get(&EmptyKey, &authorization.key_id)
 		.await?
-		.filter(|k| !k.deleted)
+		.filter(|k| !k.deleted.get())
 		.ok_or(Error::Forbidden(format!(
 			"No such key: {}",
 			authorization.key_id

src/garage/admin_rpc.rs

@@ -2,9 +2,9 @@ use std::sync::Arc;
 
 use serde::{Deserialize, Serialize};
 
-use garage_util::data::*;
 use garage_util::error::Error;
 
+use garage_table::crdt::CRDT;
 use garage_table::*;
 
 use garage_rpc::rpc_client::*;
@@ -79,25 +79,26 @@ impl AdminRpcHandler {
 				Ok(AdminRPC::BucketInfo(bucket))
 			}
 			BucketOperation::Create(query) => {
-				let bucket = self.garage.bucket_table.get(&EmptyKey, &query.name).await?;
+				let bucket = match self.garage.bucket_table.get(&EmptyKey, &query.name).await? {
-				if bucket.as_ref().filter(|b| !b.deleted).is_some() {
+					Some(mut bucket) => {
-					return Err(Error::BadRPC(format!(
+						if !bucket.is_deleted() {
-						"Bucket {} already exists",
+							return Err(Error::BadRPC(format!(
-						query.name
+								"Bucket {} already exists",
-					)));
+								query.name
-				}
+							)));
-				let new_time = match bucket {
+						}
-					Some(b) => std::cmp::max(b.timestamp + 1, now_msec()),
+						bucket
-					None => now_msec(),
+							.state
+							.update(BucketState::Present(crdt::LWWMap::new()));
+						bucket
+					}
+					None => Bucket::new(query.name.clone()),
 				};
-				self.garage
+				self.garage.bucket_table.insert(&bucket).await?;
-					.bucket_table
-					.insert(&Bucket::new(query.name.clone(), new_time, false, vec![]))
-					.await?;
 				Ok(AdminRPC::Ok(format!("Bucket {} was created.", query.name)))
 			}
 			BucketOperation::Delete(query) => {
-				let bucket = self.get_existing_bucket(&query.name).await?;
+				let mut bucket = self.get_existing_bucket(&query.name).await?;
 				let objects = self
 					.garage
 					.object_table
@@ -112,25 +113,18 @@ impl AdminRpcHandler {
 					)));
 				}
 				// --- done checking, now commit ---
-				for ak in bucket.authorized_keys() {
+				for (key_id, _, _) in bucket.authorized_keys() {
-					if let Some(key) = self.garage.key_table.get(&EmptyKey, &ak.key_id).await? {
+					if let Some(key) = self.garage.key_table.get(&EmptyKey, key_id).await? {
-						if !key.deleted {
+						if !key.deleted.get() {
 							self.update_key_bucket(key, &bucket.name, false, false)
 								.await?;
 						}
 					} else {
-						return Err(Error::Message(format!("Key not found: {}", ak.key_id)));
+						return Err(Error::Message(format!("Key not found: {}", key_id)));
 					}
 				}
-				self.garage
+				bucket.state.update(BucketState::Deleted);
-					.bucket_table
+				self.garage.bucket_table.insert(&bucket).await?;
-					.insert(&Bucket::new(
-						query.name.clone(),
-						std::cmp::max(bucket.timestamp + 1, now_msec()),
-						true,
-						vec![],
-					))
-					.await?;
 				Ok(AdminRPC::Ok(format!("Bucket {} was deleted.", query.name)))
 			}
 			BucketOperation::Allow(query) => {
@@ -173,7 +167,7 @@ impl AdminRpcHandler {
 					.get_range(&EmptyKey, None, Some(DeletedFilter::NotDeleted), 10000)
 					.await?
 					.iter()
-					.map(|k| (k.key_id.to_string(), k.name.to_string()))
+					.map(|k| (k.key_id.to_string(), k.name.get().clone()))
 					.collect::<Vec<_>>();
 				Ok(AdminRPC::KeyList(key_ids))
 			}
@@ -182,14 +176,13 @@ impl AdminRpcHandler {
 				Ok(AdminRPC::KeyInfo(key))
 			}
 			KeyOperation::New(query) => {
-				let key = Key::new(query.name, vec![]);
+				let key = Key::new(query.name);
 				self.garage.key_table.insert(&key).await?;
 				Ok(AdminRPC::KeyInfo(key))
 			}
 			KeyOperation::Rename(query) => {
 				let mut key = self.get_existing_key(&query.key_id).await?;
-				key.name_timestamp = std::cmp::max(key.name_timestamp + 1, now_msec());
+				key.name.update(query.new_name);
-				key.name = query.new_name;
 				self.garage.key_table.insert(&key).await?;
 				Ok(AdminRPC::KeyInfo(key))
 			}
@@ -201,16 +194,14 @@ impl AdminRpcHandler {
 					)));
 				}
 				// --- done checking, now commit ---
-				for ab in key.authorized_buckets().iter() {
+				for (ab_name, _, _) in key.authorized_buckets.items().iter() {
-					if let Some(bucket) =
+					if let Some(bucket) = self.garage.bucket_table.get(&EmptyKey, ab_name).await? {
-						self.garage.bucket_table.get(&EmptyKey, &ab.bucket).await?
+						if !bucket.is_deleted() {
-					{
-						if !bucket.deleted {
 							self.update_bucket_key(bucket, &key.key_id, false, false)
 								.await?;
 						}
 					} else {
-						return Err(Error::Message(format!("Bucket not found: {}", ab.bucket)));
+						return Err(Error::Message(format!("Bucket not found: {}", ab_name)));
 					}
 				}
 				let del_key = Key::delete(key.key_id);
@@ -228,7 +219,7 @@ impl AdminRpcHandler {
 			.bucket_table
 			.get(&EmptyKey, bucket)
 			.await?
-			.filter(|b| !b.deleted)
+			.filter(|b| !b.is_deleted())
 			.map(Ok)
 			.unwrap_or(Err(Error::BadRPC(format!(
 				"Bucket {} does not exist",
@@ -241,7 +232,7 @@ impl AdminRpcHandler {
 			.key_table
 			.get(&EmptyKey, id)
 			.await?
-			.filter(|k| !k.deleted)
+			.filter(|k| !k.deleted.get())
 			.map(Ok)
 			.unwrap_or(Err(Error::BadRPC(format!("Key {} does not exist", id))))
 	}
@@ -253,23 +244,20 @@ impl AdminRpcHandler {
 		allow_read: bool,
 		allow_write: bool,
 	) -> Result<(), Error> {
-		let timestamp = match bucket
+		if let BucketState::Present(ak) = bucket.state.get_mut() {
-			.authorized_keys()
+			let old_ak = ak.take_and_clear();
-			.iter()
+			ak.merge(&old_ak.update_mutator(
-			.find(|x| x.key_id == *key_id)
+				key_id.to_string(),
-		{
+				PermissionSet {
-			None => now_msec(),
+					allow_read,
-			Some(ab) => std::cmp::max(ab.timestamp + 1, now_msec()),
+					allow_write,
-		};
+				},
-		bucket.clear_keys();
+			));
-		bucket
+		} else {
-			.add_key(AllowedKey {
+			return Err(Error::Message(format!(
-				key_id: key_id.clone(),
+				"Bucket is deleted in update_bucket_key"
-				timestamp,
+			)));
-				allow_read,
+		}
-				allow_write,
-			})
-			.unwrap();
 		self.garage.bucket_table.insert(&bucket).await?;
 		Ok(())
 	}
@@ -281,22 +269,14 @@ impl AdminRpcHandler {
 		allow_read: bool,
 		allow_write: bool,
 	) -> Result<(), Error> {
-		let timestamp = match key
+		let old_map = key.authorized_buckets.take_and_clear();
-			.authorized_buckets()
+		key.authorized_buckets.merge(&old_map.update_mutator(
-			.iter()
+			bucket.clone(),
-			.find(|x| x.bucket == *bucket)
+			PermissionSet {
-		{
+				allow_read,
-			None => now_msec(),
+				allow_write,
-			Some(ab) => std::cmp::max(ab.timestamp + 1, now_msec()),
+			},
-		};
+		));
-		key.clear_buckets();
-		key.add_bucket(AllowedBucket {
-			bucket: bucket.clone(),
-			timestamp,
-			allow_read,
-			allow_write,
-		})
-		.unwrap();
 		self.garage.key_table.insert(&key).await?;
 		Ok(())
 	}

src/model/block.rs

@@ -20,7 +20,7 @@ use garage_rpc::rpc_client::*;
 use garage_rpc::rpc_server::*;
 
 use garage_table::table_sharded::TableShardedReplication;
-use garage_table::{TableReplication, DeletedFilter};
+use garage_table::{DeletedFilter, TableReplication};
 
 use crate::block_ref_table::*;
 

src/model/bucket_table.rs

@@ -1,69 +1,58 @@
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 
+use garage_table::crdt::CRDT;
 use garage_table::*;
+
 use garage_util::error::Error;
 
+use crate::key_table::PermissionSet;
+
+use model010::bucket_table as prev;
+
 #[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
 pub struct Bucket {
 	// Primary key
 	pub name: String,
 
-	// Timestamp and deletion
+	pub state: crdt::LWW<BucketState>,
-	// Upon version increment, all info is replaced
-	pub timestamp: u64,
-	pub deleted: bool,
-
-	// Authorized keys
-	authorized_keys: Vec<AllowedKey>,
-}
-
-impl Bucket {
-	pub fn new(
-		name: String,
-		timestamp: u64,
-		deleted: bool,
-		authorized_keys: Vec<AllowedKey>,
-	) -> Self {
-		let mut ret = Bucket {
-			name,
-			timestamp,
-			deleted,
-			authorized_keys: vec![],
-		};
-		for key in authorized_keys {
-			ret.add_key(key)
-				.expect("Duplicate AllowedKey in Bucket constructor");
-		}
-		ret
-	}
-	/// Add a key only if it is not already present
-	pub fn add_key(&mut self, key: AllowedKey) -> Result<(), ()> {
-		match self
-			.authorized_keys
-			.binary_search_by(|k| k.key_id.cmp(&key.key_id))
-		{
-			Err(i) => {
-				self.authorized_keys.insert(i, key);
-				Ok(())
-			}
-			Ok(_) => Err(()),
-		}
-	}
-	pub fn authorized_keys(&self) -> &[AllowedKey] {
-		&self.authorized_keys[..]
-	}
-	pub fn clear_keys(&mut self) {
-		self.authorized_keys.clear();
-	}
 }
 
 #[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
-pub struct AllowedKey {
+pub enum BucketState {
-	pub key_id: String,
+	Deleted,
-	pub timestamp: u64,
+	Present(crdt::LWWMap<String, PermissionSet>),
-	pub allow_read: bool,
+}
-	pub allow_write: bool,
+
+impl CRDT for BucketState {
+	fn merge(&mut self, o: &Self) {
+		match o {
+			BucketState::Deleted => *self = BucketState::Deleted,
+			BucketState::Present(other_ak) => {
+				if let BucketState::Present(ak) = self {
+					ak.merge(other_ak);
+				}
+			}
+		}
+	}
+}
+
+impl Bucket {
+	pub fn new(name: String) -> Self {
+		Bucket {
+			name,
+			state: crdt::LWW::new(BucketState::Present(crdt::LWWMap::new())),
+		}
+	}
+	pub fn is_deleted(&self) -> bool {
+		*self.state.get() == BucketState::Deleted
+	}
+	pub fn authorized_keys(&self) -> &[(String, u64, PermissionSet)] {
+		match self.state.get() {
+			BucketState::Deleted => &[],
+			BucketState::Present(ak) => ak.items(),
+		}
+	}
 }
 
 impl Entry<EmptyKey, String> for Bucket {
@@ -75,36 +64,12 @@ impl Entry<EmptyKey, String> for Bucket {
 	}
 
 	fn merge(&mut self, other: &Self) {
-		if other.timestamp > self.timestamp {
+		self.state.merge(&other.state);
-			*self = other.clone();
-			return;
-		}
-		if self.timestamp > other.timestamp || self.deleted {
-			return;
-		}
-
-		for ak in other.authorized_keys.iter() {
-			match self
-				.authorized_keys
-				.binary_search_by(|our_ak| our_ak.key_id.cmp(&ak.key_id))
-			{
-				Ok(i) => {
-					let our_ak = &mut self.authorized_keys[i];
-					if ak.timestamp > our_ak.timestamp {
-						*our_ak = ak.clone();
-					}
-				}
-				Err(i) => {
-					self.authorized_keys.insert(i, ak.clone());
-				}
-			}
-		}
 	}
 }
 
 pub struct BucketTable;
 
-
 #[async_trait]
 impl TableSchema for BucketTable {
 	type P = EmptyKey;
@@ -117,6 +82,35 @@ impl TableSchema for BucketTable {
 	}
 
 	fn matches_filter(entry: &Self::E, filter: &Self::Filter) -> bool {
-		filter.apply(entry.deleted)
+		filter.apply(entry.is_deleted())
+	}
+
+	fn try_migrate(bytes: &[u8]) -> Option<Self::E> {
+		let old = match rmp_serde::decode::from_read_ref::<_, prev::Bucket>(bytes) {
+			Ok(x) => x,
+			Err(_) => return None,
+		};
+		if old.deleted {
+			Some(Bucket {
+				name: old.name,
+				state: crdt::LWW::migrate_from_raw(old.timestamp, BucketState::Deleted),
+			})
+		} else {
+			let mut keys = crdt::LWWMap::new();
+			for ak in old.authorized_keys() {
+				keys.merge(&crdt::LWWMap::migrate_from_raw_item(
+					ak.key_id.clone(),
+					ak.timestamp,
+					PermissionSet {
+						allow_read: ak.allow_read,
+						allow_write: ak.allow_write,
+					},
+				));
+			}
+			Some(Bucket {
+				name: old.name,
+				state: crdt::LWW::migrate_from_raw(old.timestamp, BucketState::Present(keys)),
+			})
+		}
 	}
 }

src/model/key_table.rs

@@ -1,10 +1,13 @@
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 
+use garage_table::crdt::CRDT;
 use garage_table::*;
-use garage_util::data::*;
+
 use garage_util::error::Error;
 
+use model010::key_table as prev;
+
 #[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
 pub struct Key {
 	// Primary key
@@ -14,83 +17,54 @@ pub struct Key {
 	pub secret_key: String,
 
 	// Name
-	pub name: String,
+	pub name: crdt::LWW<String>,
-	pub name_timestamp: u64,
 
 	// Deletion
-	pub deleted: bool,
+	pub deleted: crdt::Bool,
 
 	// Authorized keys
-	authorized_buckets: Vec<AllowedBucket>,
+	pub authorized_buckets: crdt::LWWMap<String, PermissionSet>,
+	// CRDT interaction: deleted implies authorized_buckets is empty
 }
 
 impl Key {
-	pub fn new(name: String, buckets: Vec<AllowedBucket>) -> Self {
+	pub fn new(name: String) -> Self {
 		let key_id = format!("GK{}", hex::encode(&rand::random::<[u8; 12]>()[..]));
 		let secret_key = hex::encode(&rand::random::<[u8; 32]>()[..]);
-		let mut ret = Self {
+		Self {
 			key_id,
 			secret_key,
-			name,
+			name: crdt::LWW::new(name),
-			name_timestamp: now_msec(),
+			deleted: crdt::Bool::new(false),
-			deleted: false,
+			authorized_buckets: crdt::LWWMap::new(),
-			authorized_buckets: vec![],
-		};
-		for b in buckets {
-			ret.add_bucket(b)
-				.expect("Duplicate AllowedBucket in Key constructor");
 		}
-		ret
 	}
 	pub fn delete(key_id: String) -> Self {
 		Self {
 			key_id,
 			secret_key: "".into(),
-			name: "".into(),
+			name: crdt::LWW::new("".to_string()),
-			name_timestamp: now_msec(),
+			deleted: crdt::Bool::new(true),
-			deleted: true,
+			authorized_buckets: crdt::LWWMap::new(),
-			authorized_buckets: vec![],
 		}
 	}
 	/// Add an authorized bucket, only if it wasn't there before
-	pub fn add_bucket(&mut self, new: AllowedBucket) -> Result<(), ()> {
-		match self
-			.authorized_buckets
-			.binary_search_by(|b| b.bucket.cmp(&new.bucket))
-		{
-			Err(i) => {
-				self.authorized_buckets.insert(i, new);
-				Ok(())
-			}
-			Ok(_) => Err(()),
-		}
-	}
-	pub fn authorized_buckets(&self) -> &[AllowedBucket] {
-		&self.authorized_buckets[..]
-	}
-	pub fn clear_buckets(&mut self) {
-		self.authorized_buckets.clear();
-	}
 	pub fn allow_read(&self, bucket: &str) -> bool {
 		self.authorized_buckets
-			.iter()
+			.get(&bucket.to_string())
-			.find(|x| x.bucket.as_str() == bucket)
 			.map(|x| x.allow_read)
 			.unwrap_or(false)
 	}
 	pub fn allow_write(&self, bucket: &str) -> bool {
 		self.authorized_buckets
-			.iter()
+			.get(&bucket.to_string())
-			.find(|x| x.bucket.as_str() == bucket)
 			.map(|x| x.allow_write)
 			.unwrap_or(false)
 	}
 }
 
-#[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
+#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Debug, Serialize, Deserialize)]
-pub struct AllowedBucket {
+pub struct PermissionSet {
-	pub bucket: String,
-	pub timestamp: u64,
 	pub allow_read: bool,
 	pub allow_write: bool,
 }
@@ -104,35 +78,15 @@ impl Entry<EmptyKey, String> for Key {
 	}
 
 	fn merge(&mut self, other: &Self) {
-		if other.name_timestamp > self.name_timestamp {
+		self.name.merge(&other.name);
-			self.name_timestamp = other.name_timestamp;
+		self.deleted.merge(&other.deleted);
-			self.name = other.name.clone();
-		}
 
-		if other.deleted {
+		if self.deleted.get() {
-			self.deleted = true;
-		}
-		if self.deleted {
 			self.authorized_buckets.clear();
 			return;
 		}
 
-		for ab in other.authorized_buckets.iter() {
+		self.authorized_buckets.merge(&other.authorized_buckets);
-			match self
-				.authorized_buckets
-				.binary_search_by(|our_ab| our_ab.bucket.cmp(&ab.bucket))
-			{
-				Ok(i) => {
-					let our_ab = &mut self.authorized_buckets[i];
-					if ab.timestamp > our_ab.timestamp {
-						*our_ab = ab.clone();
-					}
-				}
-				Err(i) => {
-					self.authorized_buckets.insert(i, ab.clone());
-				}
-			}
-		}
 	}
 }
 
@@ -150,6 +104,32 @@ impl TableSchema for KeyTable {
 	}
 
 	fn matches_filter(entry: &Self::E, filter: &Self::Filter) -> bool {
-		filter.apply(entry.deleted)
+		filter.apply(entry.deleted.get())
+	}
+
+	fn try_migrate(bytes: &[u8]) -> Option<Self::E> {
+		let old = match rmp_serde::decode::from_read_ref::<_, prev::Key>(bytes) {
+			Ok(x) => x,
+			Err(_) => return None,
+		};
+		let mut new = Self::E {
+			key_id: old.key_id.clone(),
+			secret_key: old.secret_key.clone(),
+			name: crdt::LWW::migrate_from_raw(old.name_timestamp, old.name.clone()),
+			deleted: crdt::Bool::new(old.deleted),
+			authorized_buckets: crdt::LWWMap::new(),
+		};
+		for ab in old.authorized_buckets() {
+			let it = crdt::LWWMap::migrate_from_raw_item(
+				ab.bucket.clone(),
+				ab.timestamp,
+				PermissionSet {
+					allow_read: ab.allow_read,
+					allow_write: ab.allow_write,
+				},
+			);
+			new.authorized_buckets.merge(&it);
+		}
+		Some(new)
 	}
 }

src/table/Cargo.toml

@@ -21,6 +21,7 @@ rand = "0.7"
 hex = "0.3"
 arc-swap = "0.4"
 log = "0.4"
+hexdump = "0.1"
 
 sled = "0.31"
 

src/table/crdt.rs

@@ -0,0 +1,162 @@
+use serde::{Deserialize, Serialize};
+
+use garage_util::data::*;
+
+pub trait CRDT {
+	fn merge(&mut self, other: &Self);
+}
+
+impl<T> CRDT for T
+where
+	T: Ord + Clone,
+{
+	fn merge(&mut self, other: &Self) {
+		if other > self {
+			*self = other.clone();
+		}
+	}
+}
+
+// ---- LWW Register ----
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct LWW<T> {
+	ts: u64,
+	v: T,
+}
+
+impl<T> LWW<T>
+where
+	T: CRDT,
+{
+	pub fn new(value: T) -> Self {
+		Self {
+			ts: now_msec(),
+			v: value,
+		}
+	}
+	pub fn migrate_from_raw(ts: u64, value: T) -> Self {
+		Self { ts, v: value }
+	}
+	pub fn update(&mut self, new_value: T) {
+		self.ts = std::cmp::max(self.ts + 1, now_msec());
+		self.v = new_value;
+	}
+	pub fn get(&self) -> &T {
+		&self.v
+	}
+	pub fn get_mut(&mut self) -> &mut T {
+		&mut self.v
+	}
+}
+
+impl<T> CRDT for LWW<T>
+where
+	T: Clone + CRDT,
+{
+	fn merge(&mut self, other: &Self) {
+		if other.ts > self.ts {
+			self.ts = other.ts;
+			self.v = other.v.clone();
+		} else if other.ts == self.ts {
+			self.v.merge(&other.v);
+		}
+	}
+}
+
+// ---- Boolean (true as absorbing state) ----
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+pub struct Bool(bool);
+
+impl Bool {
+	pub fn new(b: bool) -> Self {
+		Self(b)
+	}
+	pub fn set(&mut self) {
+		self.0 = true;
+	}
+	pub fn get(&self) -> bool {
+		self.0
+	}
+}
+
+impl CRDT for Bool {
+	fn merge(&mut self, other: &Self) {
+		self.0 = self.0 || other.0;
+	}
+}
+
+// ---- LWW Map ----
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct LWWMap<K, V> {
+	vals: Vec<(K, u64, V)>,
+}
+
+impl<K, V> LWWMap<K, V>
+where
+	K: Ord,
+	V: CRDT,
+{
+	pub fn new() -> Self {
+		Self { vals: vec![] }
+	}
+	pub fn migrate_from_raw_item(k: K, ts: u64, v: V) -> Self {
+		Self {
+			vals: vec![(k, ts, v)],
+		}
+	}
+	pub fn take_and_clear(&mut self) -> Self {
+		let vals = std::mem::replace(&mut self.vals, vec![]);
+		Self { vals }
+	}
+	pub fn clear(&mut self) {
+		self.vals.clear();
+	}
+	pub fn update_mutator(&self, k: K, new_v: V) -> Self {
+		let new_vals = match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(&k)) {
+			Ok(i) => {
+				let (_, old_ts, _) = self.vals[i];
+				let new_ts = std::cmp::max(old_ts + 1, now_msec());
+				vec![(k, new_ts, new_v)]
+			}
+			Err(_) => vec![(k, now_msec(), new_v)],
+		};
+		Self { vals: new_vals }
+	}
+	pub fn get(&self, k: &K) -> Option<&V> {
+		match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(&k)) {
+			Ok(i) => Some(&self.vals[i].2),
+			Err(_) => None,
+		}
+	}
+	pub fn items(&self) -> &[(K, u64, V)] {
+		&self.vals[..]
+	}
+}
+
+impl<K, V> CRDT for LWWMap<K, V>
+where
+	K: Clone + Ord,
+	V: Clone + CRDT,
+{
+	fn merge(&mut self, other: &Self) {
+		for (k, ts2, v2) in other.vals.iter() {
+			match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(&k)) {
+				Ok(i) => {
+					let (_, ts1, _v1) = &self.vals[i];
+					if ts2 > ts1 {
+						self.vals[i].1 = *ts2;
+						self.vals[i].2 = v2.clone();
+					} else if ts1 == ts2 {
+						self.vals[i].2.merge(&v2);
+					}
+				}
+				Err(i) => {
+					self.vals.insert(i, (k.clone(), *ts2, v2.clone()));
+				}
+			}
+		}
+	}
+}

src/table/lib.rs

@@ -3,6 +3,7 @@
 #[macro_use]
 extern crate log;
 
+pub mod crdt;
 pub mod schema;
 pub mod util;
 
@@ -12,5 +13,5 @@ pub mod table_sharded;
 pub mod table_sync;
 
 pub use schema::*;
-pub use util::*;
 pub use table::*;
+pub use util::*;

src/table/schema.rs

@@ -20,7 +20,6 @@ impl PartitionKey for Hash {
 	}
 }
 
-
 pub trait SortKey {
 	fn sort_key(&self) -> &[u8];
 }
@@ -37,7 +36,6 @@ impl SortKey for Hash {
 	}
 }
 
-
 pub trait Entry<P: PartitionKey, S: SortKey>:
 	PartialEq + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync
 {
@@ -47,7 +45,6 @@ pub trait Entry<P: PartitionKey, S: SortKey>:
 	fn merge(&mut self, other: &Self);
 }
 
-
 #[async_trait]
 pub trait TableSchema: Send + Sync {
 	type P: PartitionKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
@@ -66,4 +63,3 @@ pub trait TableSchema: Send + Sync {
 		true
 	}
 }
-

src/table/table.rs

@@ -2,6 +2,8 @@ use std::collections::{BTreeMap, HashMap};
 use std::sync::Arc;
 use std::time::Duration;
 
+use log::warn;
+
 use arc_swap::ArcSwapOption;
 use futures::stream::*;
 use serde::{Deserialize, Serialize};
@@ -185,7 +187,7 @@ where
 		for resp in resps {
 			if let TableRPC::ReadEntryResponse(value) = resp {
 				if let Some(v_bytes) = value {
-					let v = Self::decode_entry(v_bytes.as_slice())?;
+					let v = self.decode_entry(v_bytes.as_slice())?;
 					ret = match ret {
 						None => Some(v),
 						Some(mut x) => {
@@ -241,7 +243,7 @@ where
 		for resp in resps {
 			if let TableRPC::Update(entries) = resp {
 				for entry_bytes in entries.iter() {
-					let entry = Self::decode_entry(entry_bytes.as_slice())?;
+					let entry = self.decode_entry(entry_bytes.as_slice())?;
 					let entry_key = self.tree_key(entry.partition_key(), entry.sort_key());
 					match ret.remove(&entry_key) {
 						None => {
@@ -363,7 +365,7 @@ where
 			let keep = match filter {
 				None => true,
 				Some(f) => {
-					let entry = Self::decode_entry(value.as_ref())?;
+					let entry = self.decode_entry(value.as_ref())?;
 					F::matches_filter(&entry, f)
 				}
 			};
@@ -382,14 +384,14 @@ where
 		let mut epidemic_propagate = vec![];
 
 		for update_bytes in entries.iter() {
-			let update = Self::decode_entry(update_bytes.as_slice())?;
+			let update = self.decode_entry(update_bytes.as_slice())?;
 
 			let tree_key = self.tree_key(update.partition_key(), update.sort_key());
 
 			let (old_entry, new_entry) = self.store.transaction(|db| {
 				let (old_entry, new_entry) = match db.get(&tree_key)? {
 					Some(prev_bytes) => {
-						let old_entry = Self::decode_entry(&prev_bytes)
+						let old_entry = self.decode_entry(&prev_bytes)
 							.map_err(sled::ConflictableTransactionError::Abort)?;
 						let mut new_entry = old_entry.clone();
 						new_entry.merge(&update);
@@ -437,7 +439,7 @@ where
 				break;
 			}
 			if let Some(old_val) = self.store.remove(&key)? {
-				let old_entry = Self::decode_entry(&old_val)?;
+				let old_entry = self.decode_entry(&old_val)?;
 				self.instance.updated(Some(old_entry), None).await?;
 				self.system
 					.background
@@ -455,12 +457,18 @@ where
 		ret
 	}
 
-	fn decode_entry(bytes: &[u8]) -> Result<F::E, Error> {
+	fn decode_entry(&self, bytes: &[u8]) -> Result<F::E, Error> {
 		match rmp_serde::decode::from_read_ref::<_, F::E>(bytes) {
 			Ok(x) => Ok(x),
 			Err(e) => match F::try_migrate(bytes) {
 				Some(x) => Ok(x),
-				None => Err(e.into()),
+				None => {
+					warn!("Unable to decode entry of {}: {}", self.name, e);
+					for line in hexdump::hexdump_iter(bytes) {
+						debug!("{}", line);
+					}
+					Err(e.into())
+				}
 			},
 		}
 	}