Struct NodeBuilder 

pub struct NodeBuilder<SE, SM>
where
    SE: StorageEngine + Debug,
    SM: StateMachine + Debug,
{ /* private fields */ }

Builder pattern implementation for constructing a Raft node with configurable components. Provides a fluent interface to set up node configuration, storage, transport, and other dependencies.

Implementations

impl<SE, SM> NodeBuilder<SE, SM>

where SE: StorageEngine + Debug, SM: StateMachine + Debug,

pub fn new(cluster_path: Option<&str>, shutdown_signal: Receiver<()>) -> Self

Creates a new NodeBuilder with cluster configuration loaded from file

Arguments

• cluster_path - Optional path to node-specific cluster configuration
• shutdown_signal - Watch channel for graceful shutdown signaling

Panics

Will panic if configuration loading fails (consider returning Result instead)

pub fn from_cluster_config( cluster_config: ClusterConfig, shutdown_signal: Receiver<()>, ) -> Self

Constructs NodeBuilder from in-memory cluster configuration

Arguments

• cluster_config - Pre-built cluster configuration
• shutdown_signal - Graceful shutdown notification channel

Usage

let builder = NodeBuilder::from_cluster_config(my_config, shutdown_rx);

pub fn init(node_config: RaftNodeConfig, shutdown_signal: Receiver<()>) -> Self

Core initialization logic shared by all construction paths

pub fn storage_engine(self, storage_engine: Arc<SE>) -> Self

Sets a custom storage engine implementation

pub fn state_machine(self, state_machine: Arc<SM>) -> Self

Sets a custom state machine implementation

pub fn node_config(self, node_config: RaftNodeConfig) -> Self

Replaces the entire node configuration

pub fn raft_config(self, config: RaftConfig) -> Self

Replaces the raft configuration

pub fn build(self) -> Self

Finalizes the builder and constructs the Raft node instance.

Initializes default implementations for any unconfigured components:

• Creates file-based databases for state machine and logs
• Sets up default gRPC transport
• Initializes commit handling subsystem
• Configures membership management

Panics

Panics if essential components cannot be initialized

pub fn with_custom_state_machine_handler( self, handler: Arc<SMHOF<RaftTypeConfig<SE, SM>>>, ) -> Self

Sets a custom state machine handler implementation.

This allows developers to provide their own implementation of the state machine handler which processes committed log entries and applies them to the state machine.

Arguments

• handler - custom state machine handler that must implement the StateMachineHandler trait

Notes

• The handler must be thread-safe as it will be shared across multiple threads
• If not set, a default implementation will be used during build()
• The handler should properly handle snapshot creation and restoration

pub fn set_snapshot_policy( self, snapshot_policy: SNP<RaftTypeConfig<SE, SM>>, ) -> Self

pub async fn start_rpc_server(self) -> Self

Starts the gRPC server for cluster communication.

Panics

Panics if node hasn’t been built or address binding fails

pub fn ready(self) -> Result<Arc<Node<RaftTypeConfig<SE, SM>>>>

Returns the built node instance after successful construction.

Errors

Returns Error::NodeFailedToStartError if build hasn’t completed