Pass on the request args directly to request vote.

src/lib.rs

@@ -249,7 +249,8 @@ impl Raft {
     }
 
     fn run_election(&self) {
-        let (term, last_log_index, last_log_term, cancel_token) = {
+        let me = self.me;
+        let (term, args, cancel_token) = {
             let mut rf = self.inner_state.lock();
 
             let (tx, rx) = futures::channel::oneshot::channel();
@@ -264,16 +265,21 @@ impl Raft {
 
             rf.persist();
 
+            let term = rf.current_term;
+            let (last_log_index, last_log_term) = rf.last_log_index_and_term();
+
             (
-                rf.current_term,
-                rf.log.len() - 1,
-                rf.log.last().unwrap().term,
+                term,
+                RequestVoteArgs {
+                    term,
+                    candidate_id: me,
+                    last_log_index,
+                    last_log_term,
+                },
                 rx,
             )
         };
 
-        let me = self.me;
-
         let mut votes = vec![];
         for (index, rpc_client) in self.peers.iter().enumerate() {
             if index != self.me.0 {
@@ -284,9 +290,7 @@ impl Raft {
                 let one_vote = tokio::spawn(Self::request_one_vote(
                     rpc_client,
                     term,
-                    me,
-                    last_log_index,
-                    last_log_term,
+                    args.clone(),
                 ));
                 // Futures must be pinned so that they have Unpin, as required
                 // by futures::future::select.
@@ -303,20 +307,14 @@ impl Raft {
         ));
     }
 
+    const REQUEST_VOTE_RETRY: usize = 4;
     async fn request_one_vote(
         rpc_client: RpcClient,
         term: Term,
-        me: Peer,
-        last_log_index: usize,
-        last_log_term: Term,
+        args: RequestVoteArgs,
     ) -> Option<bool> {
-        let reply = retry_rpc(4, move |_round| {
-            rpc_client.clone().call_request_vote(RequestVoteArgs {
-                term,
-                candidate_id: me,
-                last_log_index,
-                last_log_term,
-            })
+        let reply = retry_rpc(Self::REQUEST_VOTE_RETRY, move |_round| {
+            rpc_client.clone().call_request_vote(args.clone())
         })
         .await;
         if let Ok(reply) = reply {