ezraft 0.1.1

A beginner-friendly Raft framework built on openraft
Documentation 
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//! The Raft log entry

use openraft::BasicNode;
use openraft::EntryPayload;
use openraft::LogId;
use openraft::Membership;
use openraft::entry::RaftEntry;
use openraft::entry::RaftPayload;
use openraft::log_id::RaftLogId;
use openraft::vote::leader_id_std::CommittedLeaderId;

use crate::app::EzApp;

/// Log ID type (term, index)
///
/// A tuple that implements `RaftLogId` via OpenRaft's blanket implementation.
pub type EzLogId = (u64, u64);

/// Committed leader ID: the term of the leader that proposed a log entry
pub type EzCommittedLeaderId = CommittedLeaderId<u64>;

/// Entry payload with EzRaft's node id and node types
type EzEntryPayload<T> = EntryPayload<<T as EzApp>::Request, u64, BasicNode>;

/// A Raft log entry with EzRaft's simplified log ID type
///
/// Wraps the entry's log ID (term, index) and payload.
/// This is the native Entry type used throughout EzRaft.
#[derive(serde::Deserialize, serde::Serialize)]
#[serde(bound = "")]
pub struct EzEntry<T>
where T: EzApp
{
    /// Log ID (term, index)
    pub log_id: EzLogId,

    /// Entry payload (Normal request, Blank, or Membership change)
    pub payload: EzEntryPayload<T>,
}

// Manually implement Clone to avoid T: Clone bound; only T::Request must be Clone
impl<T> Clone for EzEntry<T>
where T: EzApp
{
    fn clone(&self) -> Self {
        Self {
            log_id: self.log_id,
            payload: self.payload.clone(),
        }
    }
}

// Manually implement Debug to avoid T: Debug bound
impl<T> std::fmt::Debug for EzEntry<T>
where T: EzApp
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("EzEntry").field("log_id", &self.log_id).field("payload", &self.payload).finish()
    }
}

// Manually implement Display
impl<T> std::fmt::Display for EzEntry<T>
where T: EzApp
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "EzEntry(log_id: ({}, {}), payload: {:?})",
            self.log_id.0, self.log_id.1, self.payload
        )
    }
}

// Implement RaftPayload trait
impl<T> RaftPayload<u64, BasicNode> for EzEntry<T>
where T: EzApp
{
    fn get_membership(&self) -> Option<Membership<u64, BasicNode>> {
        self.payload.get_membership()
    }
}

// Implement openraft::RaftEntry trait so EzEntry works with OpenRaft
impl<T> RaftEntry for EzEntry<T>
where T: EzApp
{
    type CommittedLeaderId = EzCommittedLeaderId;
    type D = T::Request;
    type NodeId = u64;
    type Node = BasicNode;

    fn new(log_id: LogId<EzCommittedLeaderId>, payload: EzEntryPayload<T>) -> Self {
        Self {
            log_id: log_id.to_type(),
            payload,
        }
    }

    fn log_id_parts(&self) -> (&EzCommittedLeaderId, u64) {
        RaftLogId::log_id_parts(&self.log_id)
    }

    fn set_log_id(&mut self, new: LogId<EzCommittedLeaderId>) {
        self.log_id = new.to_type();
    }
}

#[cfg(test)]
mod tests {
    use async_trait::async_trait;

    use super::*;

    /// Deliberately not Clone: entries must clone for any `EzApp`.
    #[derive(serde::Deserialize, serde::Serialize)]
    struct Marker;

    #[async_trait]
    impl EzApp for Marker {
        type Request = String;
        type Response = String;

        async fn apply(&mut self, req: String) -> String {
            req
        }
    }

    #[test]
    fn ez_entry_clones_without_t_clone() {
        let entry = EzEntry::<Marker> {
            log_id: (7, 9),
            payload: EntryPayload::Normal("hello".to_string()),
        };

        let clone = entry.clone();
        assert_eq!((7, 9), clone.log_id);
        let EntryPayload::Normal(req) = clone.payload else {
            panic!("payload variant changed by clone");
        };
        assert_eq!("hello", req);
    }
}