raft: add tag for panic messages

src/raft/log_unstable.rs

@@ -39,15 +39,18 @@ pub struct Unstable {
     // all entries that have not yet been written to storage.
     pub entries: Vec<Entry>,
     pub offset: u64,
+
+    pub tag: String,
 }
 
 
 impl Unstable {
-    pub fn new(offset: u64) -> Unstable {
+    pub fn new(offset: u64, tag: String) -> Unstable {
         Unstable {
             offset: offset,
             snapshot: None,
             entries: vec![],
+            tag: tag,
         }
     }
     // maybe_first_index returns the index of the first possible entry in entries
@@ -152,11 +155,12 @@ impl Unstable {
 
     pub fn must_check_outofbounds(&self, lo: u64, hi: u64) {
         if lo > hi {
-            panic!("invalid unstable.slice {} > {}", lo, hi)
+            panic!("{} invalid unstable.slice {} > {}", self.tag, lo, hi)
         }
         let upper = self.offset + self.entries.len() as u64;
         if lo < self.offset || hi > upper {
-            panic!("unstable.slice[{}, {}] out of bound[{}, {}]",
+            panic!("{} unstable.slice[{}, {}] out of bound[{}, {}]",
+                   self.tag,
                    lo,
                    hi,
                    self.offset,
@@ -205,6 +209,7 @@ mod test {
                 entries: entries.map_or(vec![], |entry| vec![entry]),
                 offset: offset,
                 snapshot: snapshot,
+                ..Default::default()
             };
             let index = u.maybe_first_index();
             match index {
@@ -231,6 +236,7 @@ mod test {
                 entries: entries.map_or(vec![], |entry| vec![entry]),
                 offset: offset,
                 snapshot: snapshot,
+                ..Default::default()
             };
             let index = u.maybe_last_index();
             match index {
@@ -262,6 +268,7 @@ mod test {
                 entries: entries.map_or(vec![], |entry| vec![entry]),
                 offset: offset,
                 snapshot: snapshot,
+                ..Default::default()
             };
             let term = u.maybe_term(index);
             match term {
@@ -278,6 +285,7 @@ mod test {
             entries: vec![new_entry(5, 1)],
             offset: 5,
             snapshot: Some(new_snapshot(4, 1)),
+            ..Default::default()
         };
 
         let s = new_snapshot(6, 2);
@@ -319,6 +327,7 @@ mod test {
                 entries: entries,
                 offset: offset,
                 snapshot: snapshot,
+                ..Default::default()
             };
             u.stable_to(index, term);
             assert_eq!(u.offset, woffset);
@@ -360,6 +369,7 @@ mod test {
                 entries: entries,
                 offset: offset,
                 snapshot: snapshot,
+                ..Default::default()
             };
             u.truncate_and_append(&to_append);
             assert_eq!(u.offset, woffset);

src/raft/raft.rs

@@ -217,14 +217,15 @@ impl<T: Storage> Raft<T> {
     pub fn new(c: &Config, store: T) -> Raft<T> {
         c.validate().expect("configuration is invalid");
         let rs = store.initial_state().expect("");
-        let raft_log = RaftLog::new(store);
+        let raft_log = RaftLog::new(store, c.tag.clone());
         let mut peers: &[u64] = &c.peers;
         if !rs.conf_state.get_nodes().is_empty() {
             if !peers.is_empty() {
                 // TODO: the peers argument is always nil except in
                 // tests; the argument should be removed and these tests should be
                 // updated to specify their nodes through a snap
-                panic!("cannot specify both new(peers) and ConfState.Nodes")
+                panic!("{} cannot specify both new(peers) and ConfState.Nodes",
+                       c.tag)
             }
             peers = rs.conf_state.get_nodes();
         }
@@ -363,11 +364,11 @@ impl<T: Storage> Raft<T> {
                        to);
                 return false;
             }
-            panic!("unexpected error: {:?}", e);
+            panic!("{} unexpected error: {:?}", self.tag, e);
         }
         let snapshot = snapshot_r.unwrap();
         if snapshot.get_metadata().get_index() == 0 {
-            panic!("need non-empty snapshot");
+            panic!("{} need non-empty snapshot", self.tag);
         }
         let (sindex, sterm) = (snapshot.get_metadata().get_index(),
                                snapshot.get_metadata().get_term());
@@ -608,7 +609,7 @@ impl<T: Storage> Raft<T> {
             .expect("unexpected error getting uncommitted entries");
         let nconf = self.num_pending_conf(&ents);
         if nconf > 1 {
-            panic!("unexpected double uncommitted config entry");
+            panic!("{} unexpected double uncommitted config entry", self.tag);
         }
 
         if nconf == 1 {