Add support for model migrations

1 files changed, 19 insertions, 73 deletions

diff --git a/src/table/table.rs b/src/table/table.rs
index 94bacc60..7a5caf4f 100644
--- a/src/table/table.rs
+++ b/src/table/table.rs
@@ -3,7 +3,6 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use arc_swap::ArcSwapOption;
-use async_trait::async_trait;
 use futures::stream::*;
 use serde::{Deserialize, Serialize};
 use serde_bytes::ByteBuf;
@@ -16,6 +15,7 @@ use garage_rpc::rpc_client::*;
 use garage_rpc::rpc_server::*;
 
 use crate::table_sync::*;
+use crate::schema::*;
 
 const TABLE_RPC_TIMEOUT: Duration = Duration::from_secs(10);
 
@@ -48,70 +48,6 @@ pub enum TableRPC<F: TableSchema> {
 
 impl<F: TableSchema> RpcMessage for TableRPC<F> {}
 
-pub trait PartitionKey {
-	fn hash(&self) -> Hash;
-}
-
-pub trait SortKey {
-	fn sort_key(&self) -> &[u8];
-}
-
-pub trait Entry<P: PartitionKey, S: SortKey>:
-	PartialEq + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync
-{
-	fn partition_key(&self) -> &P;
-	fn sort_key(&self) -> &S;
-
-	fn merge(&mut self, other: &Self);
-}
-
-#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
-pub struct EmptyKey;
-impl SortKey for EmptyKey {
-	fn sort_key(&self) -> &[u8] {
-		&[]
-	}
-}
-impl PartitionKey for EmptyKey {
-	fn hash(&self) -> Hash {
-		[0u8; 32].into()
-	}
-}
-
-impl PartitionKey for String {
-	fn hash(&self) -> Hash {
-		hash(self.as_bytes())
-	}
-}
-impl SortKey for String {
-	fn sort_key(&self) -> &[u8] {
-		self.as_bytes()
-	}
-}
-
-impl PartitionKey for Hash {
-	fn hash(&self) -> Hash {
-		self.clone()
-	}
-}
-impl SortKey for Hash {
-	fn sort_key(&self) -> &[u8] {
-		self.as_slice()
-	}
-}
-
-#[async_trait]
-pub trait TableSchema: Send + Sync {
-	type P: PartitionKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
-	type S: SortKey + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
-	type E: Entry<Self::P, Self::S>;
-	type Filter: Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
-
-	async fn updated(&self, old: Option<Self::E>, new: Option<Self::E>) -> Result<(), Error>;
-	fn matches_filter(_entry: &Self::E, _filter: &Self::Filter) -> bool {
-		true
-	}
-}
 
 pub trait TableReplication: Send + Sync {
 	// See examples in table_sharded.rs and table_fullcopy.rs
@@ -250,7 +186,7 @@ where
 		for resp in resps {
 			if let TableRPC::ReadEntryResponse(value) = resp {
 				if let Some(v_bytes) = value {
-					let v = rmp_serde::decode::from_read_ref::<_, F::E>(v_bytes.as_slice())?;
+					let v = Self::decode_entry(v_bytes.as_slice())?;
 					ret = match ret {
 						None => Some(v),
 						Some(mut x) => {
@@ -306,8 +242,7 @@ where
 		for resp in resps {
 			if let TableRPC::Update(entries) = resp {
 				for entry_bytes in entries.iter() {
-					let entry =
-						rmp_serde::decode::from_read_ref::<_, F::E>(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 => {
@@ -429,7 +364,7 @@ where
 			let keep = match filter {
 				None => true,
 				Some(f) => {
-					let entry = rmp_serde::decode::from_read_ref::<_, F::E>(value.as_ref())?;
+					let entry = Self::decode_entry(value.as_ref())?;
 					F::matches_filter(&entry, f)
 				}
 			};
@@ -448,15 +383,14 @@ where
 		let mut epidemic_propagate = vec![];
 
 		for update_bytes in entries.iter() {
-			let update = rmp_serde::decode::from_read_ref::<_, F::E>(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 = rmp_serde::decode::from_read_ref::<_, F::E>(&prev_bytes)
-							.map_err(Error::RMPDecode)
+						let old_entry = Self::decode_entry(&prev_bytes)
 							.map_err(sled::ConflictableTransactionError::Abort)?;
 						let mut new_entry = old_entry.clone();
 						new_entry.merge(&update);
@@ -504,7 +438,7 @@ where
 				break;
 			}
 			if let Some(old_val) = self.store.remove(&key)? {
-				let old_entry = rmp_serde::decode::from_read_ref::<_, F::E>(&old_val)?;
+				let old_entry = Self::decode_entry(&old_val)?;
 				self.instance.updated(Some(old_entry), None).await?;
 				self.system
 					.background
@@ -521,4 +455,16 @@ where
 		ret.extend(s.sort_key());
 		ret
 	}
+
+    fn decode_entry(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()),
+                 }   
+             }
+         }
+    }
 }