Feature: Group storage configuration types in StorageTypeConfig trait

This addresses #938 partially (just the outer API level).

examples/raft-kv-memstore/src/lib.rs

@@ -11,6 +11,7 @@ use actix_web::HttpServer;
 use openraft::storage::Adaptor;
 use openraft::BasicNode;
 use openraft::Config;
+use openraft::StorageTypeConfig;
 use openraft::TokioRuntime;
 
 use crate::app::App;
@@ -37,7 +38,17 @@ openraft::declare_raft_types!(
 
 pub type LogStore = Adaptor<TypeConfig, Arc<Store>>;
 pub type StateMachineStore = Adaptor<TypeConfig, Arc<Store>>;
-pub type Raft = openraft::Raft<TypeConfig, Network, LogStore, StateMachineStore>;
+
+/// Storage types configuration for `openraft`.
+pub struct StorageConfig;
+
+impl StorageTypeConfig<TypeConfig> for StorageConfig {
+    type NetworkFactory = Network;
+    type LogStorage = LogStore;
+    type StateMachine = StateMachineStore;
+}
+
+pub type Raft = openraft::Raft<TypeConfig, StorageConfig>;
 
 pub mod typ {
     use openraft::BasicNode;

examples/raft-kv-rocksdb/Cargo.toml

@@ -21,7 +21,7 @@ name = "raft-key-value-rocks"
 path = "src/bin/main.rs"
 
 [dependencies]
-openraft = { path = "../../openraft", features = ["serde"] }
+openraft = { path = "../../openraft", features = ["serde", "compat-08"] }
 
 async-std = { version = "1.12.0", features = ["attributes", "tokio1"] }
 async-trait = "0.1.36"

openraft/Cargo.toml

@@ -76,9 +76,12 @@ single-term-leader = []
 compat = []
 
 # Turn on to let openraft provide additional data types to build v0.7 compatible RaftStorage.
-compat-07 = ["compat", "serde", "dep:or07", "compat-07-testing"]
+compat-07 = ["compat", "serde", "dep:or07", "compat-07-testing", "compat-08"]
 compat-07-testing = ["dep:tempfile", "anyhow", "dep:serde_json"]
 
+# Turn on compatibility with original `Raft` API with individual types for network/log/state machine.
+compat-08 = []
+
 # Allows an application to implement a custom the v2 storage API.
 # See `openraft::storage::v2` for more details.
 # V2 API are unstable and may change in the future.

openraft/src/lib.rs

@@ -61,6 +61,7 @@ pub mod log_id;
 pub mod metrics;
 pub mod network;
 pub mod raft;
+pub mod raft_compat;
 pub mod storage;
 pub mod testing;
 pub mod timer;
@@ -90,6 +91,7 @@ pub use network::RPCTypes;
 pub use network::RaftNetwork;
 pub use network::RaftNetworkFactory;
 pub use type_config::RaftTypeConfig;
+pub use type_config::StorageTypeConfig;
 
 pub use crate::async_runtime::AsyncRuntime;
 pub use crate::async_runtime::TokioRuntime;
@@ -114,7 +116,6 @@ pub use crate::node::BasicNode;
 pub use crate::node::EmptyNode;
 pub use crate::node::Node;
 pub use crate::node::NodeId;
-pub use crate::raft::Raft;
 pub use crate::raft_state::MembershipState;
 pub use crate::raft_state::RaftState;
 pub use crate::raft_types::SnapshotId;
@@ -139,6 +140,11 @@ pub use crate::vote::CommittedLeaderId;
 pub use crate::vote::LeaderId;
 pub use crate::vote::Vote;
 
+#[cfg(not(feature = "compat-08"))]
+pub use crate::raft::Raft;
+#[cfg(feature = "compat-08")]
+pub use crate::raft_compat::Raft;
+
 #[cfg(feature = "serde")]
 #[doc(hidden)]
 pub trait OptionalSerde: serde::Serialize + for<'a> serde::Deserialize<'a> {}

openraft/src/raft/mod.rs

@@ -48,12 +48,9 @@ use crate::error::RaftError;
 use crate::membership::IntoNodes;
 use crate::metrics::RaftMetrics;
 use crate::metrics::Wait;
-use crate::network::RaftNetworkFactory;
 use crate::raft::raft_inner::RaftInner;
 use crate::raft::runtime_config_handle::RuntimeConfigHandle;
 use crate::raft::trigger::Trigger;
-use crate::storage::RaftLogStorage;
-use crate::storage::RaftStateMachine;
 use crate::AsyncRuntime;
 use crate::ChangeMembers;
 use crate::LogId;
@@ -63,6 +60,7 @@ use crate::OptionalSend;
 use crate::RaftState;
 pub use crate::RaftTypeConfig;
 use crate::StorageHelper;
+pub use crate::StorageTypeConfig;
 
 /// Define types for a Raft type configuration.
 ///
@@ -124,28 +122,22 @@ macro_rules! declare_raft_types {
 /// `shutdown` method should be called on this type to await the shutdown of the node. If the parent
 /// application needs to shutdown the Raft node for any reason, calling `shutdown` will do the
 /// trick.
-pub struct Raft<C, N, LS, SM>
+pub struct Raft<C, S>
 where
     C: RaftTypeConfig,
-    N: RaftNetworkFactory<C>,
-    LS: RaftLogStorage<C>,
-    SM: RaftStateMachine<C>,
+    S: StorageTypeConfig<C>,
 {
-    inner: Arc<RaftInner<C, N, LS>>,
-    _phantom: PhantomData<SM>,
+    inner: Arc<RaftInner<C, S::NetworkFactory, S::LogStorage>>,
 }
 
-impl<C, N, LS, SM> Clone for Raft<C, N, LS, SM>
+impl<C, S> Clone for Raft<C, S>
 where
     C: RaftTypeConfig,
-    N: RaftNetworkFactory<C>,
-    LS: RaftLogStorage<C>,
-    SM: RaftStateMachine<C>,
+    S: StorageTypeConfig<C>,
 {
     fn clone(&self) -> Self {
         Self {
             inner: self.inner.clone(),
-            _phantom: PhantomData,
         }
     }
 }
@@ -159,7 +151,7 @@ where
 //
 // Notably, the state machine, log storage and network factory DO NOT have to be `Send`, those
 // are only used within Raft task(s) on a single thread.
-unsafe impl<C, N, LS, SM> Send for Raft<C, N, LS, SM>
+unsafe impl<C, S> Send for Raft<C, S>
 where
     C: RaftTypeConfig,
     N: RaftNetworkFactory<C>,
@@ -177,7 +169,7 @@ where
 // SAFETY: Even for a single-threaded Raft, the API object is MT-capable.
 //
 // See above for details.
-unsafe impl<C, N, LS, SM> Sync for Raft<C, N, LS, SM>
+unsafe impl<C, S> Sync for Raft<C, S>
 where
     C: RaftTypeConfig + Send,
     N: RaftNetworkFactory<C>,
@@ -191,12 +183,10 @@ where
 {
 }
 
-impl<C, N, LS, SM> Raft<C, N, LS, SM>
+impl<C, S> Raft<C, S>
 where
     C: RaftTypeConfig,
-    N: RaftNetworkFactory<C>,
-    LS: RaftLogStorage<C>,
-    SM: RaftStateMachine<C>,
+    S: StorageTypeConfig<C>,
 {
     /// Create and spawn a new Raft task.
     ///
@@ -221,9 +211,9 @@ where
     pub async fn new(
         id: C::NodeId,
         config: Arc<Config>,
-        network: N,
-        mut log_store: LS,
-        mut state_machine: SM,
+        network: S::NetworkFactory,
+        mut log_store: S::LogStorage,
+        mut state_machine: S::StateMachine,
     ) -> Result<Self, Fatal<C::NodeId>> {
         let (tx_api, rx_api) = mpsc::unbounded_channel();
         let (tx_notify, rx_notify) = mpsc::unbounded_channel();
@@ -257,7 +247,7 @@ where
 
         let sm_handle = sm::Worker::spawn(state_machine, tx_notify.clone());
 
-        let core: RaftCore<C, N, LS, SM> = RaftCore {
+        let core: RaftCore<C, S::NetworkFactory, S::LogStorage, S::StateMachine> = RaftCore {
             id,
             config: config.clone(),
             runtime_config: runtime_config.clone(),
@@ -295,10 +285,7 @@ where
             core_state: Mutex::new(CoreState::Running(core_handle)),
         };
 
-        Ok(Self {
-            inner: Arc::new(inner),
-            _phantom: Default::default(),
-        })
+        Ok(Self { inner: Arc::new(inner) })
     }
 
     /// Return a handle to update runtime config.
@@ -310,7 +297,7 @@ where
     /// let raft = Raft::new(...).await?;
     /// raft.runtime_config().heartbeat(true);
     /// ```
-    pub fn runtime_config(&self) -> RuntimeConfigHandle<C, N, LS> {
+    pub fn runtime_config(&self) -> RuntimeConfigHandle<C, S::NetworkFactory, S::LogStorage> {
         RuntimeConfigHandle::new(self.inner.as_ref())
     }
 
@@ -337,7 +324,7 @@ where
     /// let raft = Raft::new(...).await?;
     /// raft.trigger().elect().await?;
     /// ```
-    pub fn trigger(&self) -> Trigger<C, N, LS> {
+    pub fn trigger(&self) -> Trigger<C, S::NetworkFactory, S::LogStorage> {
         Trigger::new(self.inner.as_ref())
     }
 
@@ -694,7 +681,7 @@ where
     #[tracing::instrument(level = "debug", skip(self, mes, rx))]
     pub(crate) async fn call_core<T, E>(
         &self,
-        mes: RaftMsg<C, N, LS>,
+        mes: RaftMsg<C, S::NetworkFactory, S::LogStorage>,
         rx: oneshot::Receiver<Result<T, E>>,
     ) -> Result<T, RaftError<C::NodeId, E>>
     where
@@ -739,8 +726,11 @@ where
     /// If the API channel is already closed (Raft is in shutdown), then the request functor is
     /// destroyed right away and not called at all.
     pub fn external_request<
-        F: FnOnce(&RaftState<C::NodeId, C::Node, <C::AsyncRuntime as AsyncRuntime>::Instant>, &mut LS, &mut N)
-            + OptionalSend
+        F: FnOnce(
+                &RaftState<C::NodeId, C::Node, <C::AsyncRuntime as AsyncRuntime>::Instant>,
+                &mut S::LogStorage,
+                &mut S::NetworkFactory,
+            ) + OptionalSend
             + 'static,
     >(
         &self,

openraft/src/raft_compat.rs

@@ -0,0 +1,37 @@
+//! Compatibility layer for `Raft` with old type parameters.
+
+use crate::storage::RaftLogStorage;
+use crate::storage::RaftStateMachine;
+use crate::RaftNetworkFactory;
+use crate::RaftTypeConfig;
+use crate::StorageTypeConfig;
+use std::marker::PhantomData;
+
+/// Default type for storage configuration for compatibility.
+///
+/// This type implements [`StorageTypeConfig<C>`] with the supplied types for network,
+/// log storage and state machine.
+pub struct DefaultStorageConfig<C, N, LS, SM>
+where
+    C: RaftTypeConfig,
+    N: RaftNetworkFactory<C>,
+    LS: RaftLogStorage<C>,
+    SM: RaftStateMachine<C>,
+{
+    _phantom: PhantomData<(C, N, LS, SM)>,
+}
+
+impl<C, N, LS, SM> StorageTypeConfig<C> for DefaultStorageConfig<C, N, LS, SM>
+where
+    C: RaftTypeConfig,
+    N: RaftNetworkFactory<C>,
+    LS: RaftLogStorage<C>,
+    SM: RaftStateMachine<C>,
+{
+    type NetworkFactory = N;
+    type LogStorage = LS;
+    type StateMachine = SM;
+}
+
+/// Type alias to forward to the new `Raft` implementation.
+pub type Raft<C, N, LS, SM> = crate::raft::Raft<C, DefaultStorageConfig<C, N, LS, SM>>;

openraft/src/type_config.rs

@@ -6,13 +6,16 @@ use tokio::io::AsyncWrite;
 
 use crate::entry::FromAppData;
 use crate::entry::RaftEntry;
+use crate::storage::RaftLogStorage;
+use crate::storage::RaftStateMachine;
 use crate::AppData;
 use crate::AppDataResponse;
 use crate::AsyncRuntime;
 use crate::Node;
 use crate::NodeId;
 use crate::OptionalSend;
 use crate::OptionalSync;
+use crate::RaftNetworkFactory;
 
 /// Configuration of types used by the [`Raft`] core engine.
 ///
@@ -41,7 +44,7 @@ use crate::OptionalSync;
 /// ```
 /// [`Raft`]: crate::Raft
 pub trait RaftTypeConfig:
-    Sized + OptionalSend + OptionalSync + Debug + Clone + Copy + Default + Eq + PartialEq + Ord + PartialOrd + 'static
+    Sized + Send + Sync + Debug + Clone + Copy + Default + Eq + PartialEq + Ord + PartialOrd + 'static
 {
     /// Application-specific request data passed to the state machine.
     type D: AppData;
@@ -67,3 +70,22 @@ pub trait RaftTypeConfig:
     /// Asynchronous runtime type.
     type AsyncRuntime: AsyncRuntime;
 }
+
+/// Configuration of types used by the [`Raft`] core engine for the storage.
+///
+/// The (empty) implementation of this structure defines network factory, log storage and
+/// state machine types. Refer to the documentation of associated types for more information.
+///
+/// [`Raft`]: crate::Raft
+// : Sized + Send + Sync + Debug + Clone + Copy + Default + Eq + PartialEq + Ord + PartialOrd +
+// 'static
+pub trait StorageTypeConfig<C: RaftTypeConfig> {
+    /// Network factory to use to create new connections.
+    type NetworkFactory: RaftNetworkFactory<C>;
+
+    /// Log storage storing the deltas.
+    type LogStorage: RaftLogStorage<C>;
+
+    /// State machine processing requests and storing the snapshot of the data.
+    type StateMachine: RaftStateMachine<C>;
+}

rocksstore/Cargo.toml

@@ -16,7 +16,7 @@ repository    = { workspace = true }
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-openraft = { path= "../openraft", version = "0.8.4", features=["serde"] }
+openraft = { path= "../openraft", version = "0.8.4", features=["serde", "compat-08"] }
 
 rocksdb = "0.20.1"
 byteorder = "1.4.3"

sledstore/Cargo.toml

@@ -14,7 +14,7 @@ license       = { workspace = true }
 repository    = { workspace = true }
 
 [dependencies]
-openraft = { path= "../openraft", version = "0.8.4", features=["serde"] }
+openraft = { path= "../openraft", version = "0.8.4", features=["serde", "compat-08"] }
 
 sled = "0.34.7"
 byteorder = "1.4.3"

stores/rocksstore-v2/Cargo.toml

@@ -18,7 +18,7 @@ repository = "https://github.com/datafuselabs/openraft"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-openraft = { path= "../../openraft", version = "0.8.4", features=["serde", "storage-v2"] }
+openraft = { path= "../../openraft", version = "0.8.4", features=["serde", "storage-v2", "compat-08"] }
 
 rocksdb = "0.20.1"
 rand = "*"

tests/tests/fixtures/mod.rs

@@ -51,6 +51,7 @@ use openraft::RaftLogId;
 use openraft::RaftMetrics;
 use openraft::RaftState;
 use openraft::ServerState;
+use openraft::StorageTypeConfig;
 use openraft::TokioInstant;
 use openraft::TokioRuntime;
 use openraft::Vote;
@@ -71,8 +72,17 @@ pub mod logging;
 pub type MemLogStore = Adaptor<MemConfig, Arc<MemStore>>;
 pub type MemStateMachine = Adaptor<MemConfig, Arc<MemStore>>;
 
+/// Storage types configuration for `openraft` tests.
+pub struct StorageConfig;
+
+impl StorageTypeConfig<MemConfig> for StorageConfig {
+    type NetworkFactory = TypedRaftRouter;
+    type LogStorage = MemLogStore;
+    type StateMachine = MemStateMachine;
+}
+
 /// A concrete Raft type used during testing.
-pub type MemRaft = Raft<MemConfig, TypedRaftRouter, MemLogStore, MemStateMachine>;
+pub type MemRaft = Raft<MemConfig, TypedRaftRouter, StorageConfig>;
 
 pub fn init_default_ut_tracing() {
     static START: Once = Once::new();