consul: Ensure KVS List handles tombstones

consul/kvs_endpoint.go

@@ -135,23 +135,14 @@ func (k *KVS) List(args *structs.KeyRequest, reply *structs.IndexedDirEntries) e
 		&reply.QueryMeta,
 		state.QueryTables("KVSList"),
 		func() error {
-			index, ent, err := state.KVSList(args.Key)
+			tombIndex, index, ent, err := state.KVSList(args.Key)
 			if err != nil {
 				return err
 			}
 			if acl != nil {
 				ent = FilterDirEnt(acl, ent)
 			}
-			if len(ent) == 0 {
-				// Must provide non-zero index to prevent blocking
-				// Index 1 is impossible anyways (due to Raft internals)
-				if index == 0 {
-					reply.Index = 1
-				} else {
-					reply.Index = index
-				}
-				reply.Entries = nil
-			} else {
+
 			// Determine the maximum affected index
 			var maxIndex uint64
 			for _, e := range ent {
@@ -159,8 +150,21 @@ func (k *KVS) List(args *structs.KeyRequest, reply *structs.IndexedDirEntries) e
 					maxIndex = e.ModifyIndex
 				}
 			}
-
+			if tombIndex > maxIndex {
+				maxIndex = tombIndex
+			}
+			// Must provide non-zero index to prevent blocking
+			// Index 1 is impossible anyways (due to Raft internals)
+			if maxIndex == 0 {
+				if index > 0 {
+					maxIndex = index
+				} else {
+					maxIndex = 1
+				}
+			}
 			reply.Index = maxIndex
+
+			if len(ent) != 0 {
 				reply.Entries = ent
 			}
 			return nil

consul/state_store.go

@@ -1115,13 +1115,39 @@ func (s *StateStore) KVSGet(key string) (uint64, *structs.DirEntry, error) {
 }
 
 // KVSList is used to list all KV entries with a prefix
-func (s *StateStore) KVSList(prefix string) (uint64, structs.DirEntries, error) {
-	idx, res, err := s.kvsTable.Get("id_prefix", prefix)
+func (s *StateStore) KVSList(prefix string) (uint64, uint64, structs.DirEntries, error) {
+	tables := MDBTables{s.kvsTable, s.tombstoneTable}
+	tx, err := tables.StartTxn(true)
+	if err != nil {
+		return 0, 0, nil, err
+	}
+	defer tx.Abort()
+
+	idx, err := tables.LastIndexTxn(tx)
+	if err != nil {
+		return 0, 0, nil, err
+	}
+
+	res, err := s.kvsTable.GetTxn(tx, "id_prefix", prefix)
+	if err != nil {
+		return 0, 0, nil, err
+	}
 	ents := make(structs.DirEntries, len(res))
 	for idx, r := range res {
 		ents[idx] = r.(*structs.DirEntry)
 	}
-	return idx, ents, err
+
+	// Check for the higest index in the tombstone table
+	var maxIndex uint64
+	res, err = s.tombstoneTable.GetTxn(tx, "id_prefix", prefix)
+	for _, r := range res {
+		ent := r.(*structs.DirEntry)
+		if ent.ModifyIndex > maxIndex {
+			maxIndex = ent.ModifyIndex
+		}
+	}
+
+	return maxIndex, idx, ents, err
 }
 
 // KVSListKeys is used to list keys with a prefix, and up to a given seperator

consul/state_store_test.go

@@ -1588,7 +1588,7 @@ func TestKVS_List(t *testing.T) {
 	defer store.Close()
 
 	// Should not exist
-	idx, ents, err := store.KVSList("/web")
+	_, idx, ents, err := store.KVSList("/web")
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -1614,7 +1614,7 @@ func TestKVS_List(t *testing.T) {
 	}
 
 	// Should list
-	idx, ents, err = store.KVSList("/web")
+	_, idx, ents, err = store.KVSList("/web")
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -1636,6 +1636,55 @@ func TestKVS_List(t *testing.T) {
 	}
 }
 
+func TestKVSList_TombstoneIndex(t *testing.T) {
+	store, err := testStateStore()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	defer store.Close()
+
+	// Create the entries
+	d := &structs.DirEntry{Key: "/web/a", Value: []byte("test")}
+	if err := store.KVSSet(1000, d); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	d = &structs.DirEntry{Key: "/web/b", Value: []byte("test")}
+	if err := store.KVSSet(1001, d); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	d = &structs.DirEntry{Key: "/web/c", Value: []byte("test")}
+	if err := store.KVSSet(1002, d); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Nuke the last node
+	err = store.KVSDeleteTree(1003, "/web/c")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Add another node
+	d = &structs.DirEntry{Key: "/other", Value: []byte("test")}
+	if err := store.KVSSet(1004, d); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// List should properly reflect tombstoned value
+	tombIdx, idx, ents, err := store.KVSList("/web")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if idx != 1004 {
+		t.Fatalf("bad: %v", idx)
+	}
+	if tombIdx != 1003 {
+		t.Fatalf("bad: %v", idx)
+	}
+	if len(ents) != 2 {
+		t.Fatalf("bad: %v", ents)
+	}
+}
+
 func TestKVS_ListKeys(t *testing.T) {
 	store, err := testStateStore()
 	if err != nil {
@@ -1852,13 +1901,16 @@ func TestKVSDeleteTree(t *testing.T) {
 	}
 
 	// Nothing should list
-	idx, ents, err := store.KVSList("/web")
+	tombIdx, idx, ents, err := store.KVSList("/web")
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
 	if idx != 1010 {
 		t.Fatalf("bad: %v", idx)
 	}
+	if tombIdx != 1010 {
+		t.Fatalf("bad: %v", idx)
+	}
 	if len(ents) != 0 {
 		t.Fatalf("bad: %v", ents)
 	}