Back out "have wa_raft_storage:make_empty_snapshot return last applied log position"

Summary:
Original commit changeset: 6e8617b239d5

Original Phabricator Diff: D72344559

Reviewed By: hsun324

Differential Revision: D72418888

fbshipit-source-id: 892bcb6a6239a570cab2a5ab268e85c74215988b

Author: Sarah Hassan

src/wa_raft_server.erl

@@ -764,7 +764,7 @@ stalled({call, From}, ?BOOTSTRAP_COMMAND(#raft_log_pos{index = Index, term = Ter
                 [Name, CurrentTerm, Index, Term, Config, Data, 30], #{domain => [whatsapp, wa_raft]}),
             Path = filename:join(PartitionPath, io_lib:format("snapshot.~0p.~0p.bootstrap.tmp", [Index, Term])),
             try
-                {ok, _} = wa_raft_storage:make_empty_snapshot(Storage, Path, Position, Config, Data),
+                ok = wa_raft_storage:make_empty_snapshot(Storage, Path, Position, Config, Data),
                 ok = wa_raft_storage:open_snapshot(Storage, Path, Position),
                 {ok, NewView} = wa_raft_log:reset(View, Position),
                 State1 = State0#raft_state{log_view = NewView, last_applied = Index, commit_index = Index},

src/wa_raft_storage.erl

@@ -358,7 +358,7 @@ create_snapshot(ServiceRef) ->
 create_snapshot(ServiceRef, Name) ->
     gen_server:call(ServiceRef, {snapshot_create, Name}, ?RAFT_STORAGE_CALL_TIMEOUT()).
 
--spec make_empty_snapshot(ServiceRef :: pid() | atom(), Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: dynamic()) -> {ok, Pos :: wa_raft_log:log_pos()} | error().
+-spec make_empty_snapshot(ServiceRef :: pid() | atom(), Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: term()) -> ok | error().
 make_empty_snapshot(ServiceRef, Path, Position, Config, Data) ->
     gen_server:call(ServiceRef, {make_empty_snapshot, Path, Position, Config, Data}).
 
@@ -453,7 +453,7 @@ init(#raft_options{table = Table, partition = Partition, identifier = Identifier
         status |
         {snapshot_create, Name :: string()} |
         {snapshot_open, Path :: file:filename(), LastAppliedPos :: wa_raft_log:log_pos()} |
-        {make_empty_snapshot, Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: dynamic()} |
+        {make_empty_snapshot, Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: term()} |
         position |
         label |
         config.
@@ -467,10 +467,10 @@ handle_call(snapshot_create, From, #state{last_applied = #raft_log_pos{index = L
     Name = ?SNAPSHOT_NAME(LastIndex, LastTerm),
     handle_call({snapshot_create, Name}, From, State);
 
-handle_call({snapshot_create, Name}, _From, #state{last_applied = LastApplied} = State) ->
+handle_call({snapshot_create, Name}, _From, #state{last_applied = #raft_log_pos{index = LastIndex, term = LastTerm}} = State) ->
     case create_snapshot_impl(Name, State) of
         ok ->
-            {reply, {ok, LastApplied}, State};
+            {reply, {ok, #raft_log_pos{index = LastIndex, term = LastTerm}}, State};
         {error, _} = Error ->
             {reply, Error, State}
     end;
@@ -482,14 +482,12 @@ handle_call({snapshot_open, SnapshotPath, LogPos}, _From, #state{name = Name, mo
         {error, Reason} -> {reply, {error, Reason}, State}
     end;
 
-handle_call({make_empty_snapshot, Path, Position, Config, Data}, _From, #state{name = Name, identifier = Identifier, last_applied = LastApplied} = State) ->
+handle_call({make_empty_snapshot, Path, Position, Config, Data}, _From, #state{name = Name, identifier = Identifier, module = Module} = State) ->
     ?LOG_NOTICE("Storage[~0p] making bootstrap snapshot ~0p at ~0p with config ~0p and data ~0P.",
         [Name, Path, Position, Config, Data, 30], #{domain => [whatsapp, wa_raft]}),
-    case create_empty_snapshot_impl(Name, Identifier, Path, Position, Config, Data, State) of
-        ok ->
-            {reply, {ok, LastApplied}, State};
-        {error, _} = Error ->
-            {reply, Error, State}
+    case erlang:function_exported(Module, storage_make_empty_snapshot, 6) of
+        true -> {reply, Module:storage_make_empty_snapshot(Name, Identifier, Path, Position, Config, Data), State};
+        false -> {reply, {error, not_supported}, State}
     end;
 
 handle_call(config, _From, #state{module = Module, handle = Handle} = State) ->
@@ -639,21 +637,6 @@ create_snapshot_impl(SnapName, #state{name = Name, root_dir = RootDir, module =
             Module:storage_create_snapshot(SnapshotPath, Handle)
     end.
 
--spec create_empty_snapshot_impl(
-    Name :: atom(),
-    Identifier :: #raft_identifier{},
-    Path :: file:filename(),
-    Position :: wa_raft_log:log_pos(),
-    Config :: wa_raft_server:config(),
-    Data :: #{virtual_partition_range := kvdb_core:virtual_partition_range()},
-    Storage :: #state{}
-) -> ok | error().
-create_empty_snapshot_impl(Name, Identifier, Path, Position, Config, Data, #state{module = Module}) ->
-    case erlang:function_exported(Module, storage_make_empty_snapshot, 6) of
-        true -> Module:storage_make_empty_snapshot(Name, Identifier, Path, Position, Config, Data);
-        false -> {error, not_supported}
-    end.
-
 -define(MAX_RETAINED_SNAPSHOT, 1).
 
 -spec cleanup_snapshots(#state{}) -> ok.