Remove generic error types

Summary: Remove `wa_raft:error/0`, `wa_raft_log:error/0`, and `wa_raft_storage:error/0` generic error types

Reviewed By: jaher

Differential Revision: D76531247

fbshipit-source-id: 6110c5f24c143e8a41d032483b32a02f98e61cba

Author: hsun324

src/wa_raft.erl

@@ -14,14 +14,12 @@
 -export_type([
     table/0,
     partition/0,
-    error/0,
     args/0,
     identity/0
 ]).
 
 -type table() :: atom().
 -type partition() :: pos_integer().
--type error() :: {error, term()}.
 
 %% Specification for starting a RAFT partition.
 -type args() ::

src/wa_raft_durable_state.erl

@@ -17,7 +17,7 @@
     sync/1
 ]).
 
--spec load(StateIn :: #raft_state{}) -> {ok, StateOut :: #raft_state{}} | no_state | wa_raft:error().
+-spec load(StateIn :: #raft_state{}) -> {ok, StateOut :: #raft_state{}} | no_state | {error, Reason :: term()}.
 load(#raft_state{name = Name, partition_path = PartitionPath} = State) ->
     StateItems = [
         {current_term,   fun is_integer/1, fun (V, S) -> S#raft_state{current_term = V} end,   required},
@@ -69,7 +69,7 @@ load(#raft_state{name = Name, partition_path = PartitionPath} = State) ->
             {error, Reason}
     end.
 
--spec store(#raft_state{}) -> ok | wa_raft:error().
+-spec store(#raft_state{}) -> ok | {error, Reason :: term()}.
 store(#raft_state{name = Name, partition_path = PartitionPath, current_term = CurrentTerm, voted_for = VotedFor, disable_reason = DisableReason}) ->
     StateList = [
         {current_term, CurrentTerm},

src/wa_raft_log.erl

@@ -141,8 +141,7 @@ config(#raft_log{name = Name}) ->
 %% RAFT log provider interface for writing new log data
 %%-------------------------------------------------------------------
 
--spec append(View :: wa_raft_log:view(), Entries :: [wa_raft_log:log_entry() | binary()], Mode :: strict | relaxed) ->
-    ok | skipped | wa_raft_log:error().
+-spec append(View :: wa_raft_log:view(), Entries :: [wa_raft_log:log_entry() | binary()], Mode :: strict | relaxed) -> ok.
 append(View, Entries, _Mode) ->
     Name = wa_raft_log:log_name(View),
     Last = wa_raft_log:last_index(View),

src/wa_raft_log_ets.erl

@@ -383,7 +383,7 @@ child_spec(Options) ->
         modules => [?MODULE]
     }.
 
--spec start_link(Options :: #raft_options{}) -> {ok, Pid :: pid()} | ignore | wa_raft:error().
+-spec start_link(Options :: #raft_options{}) -> gen_server:start_ret().
 start_link(#raft_options{queue_name = Name} = Options) ->
     gen_server:start_link({local, Name}, ?MODULE, Options, []).
 

src/wa_raft_queue.erl

@@ -293,7 +293,7 @@ child_spec(Options) ->
         modules => [?MODULE]
     }.
 
--spec start_link(Options :: #raft_options{}) -> {ok, Pid :: pid()} | ignore | wa_raft:error().
+-spec start_link(Options :: #raft_options{}) -> gen_statem:start_ret().
 start_link(#raft_options{server_name = Name} = Options) ->
     gen_statem:start_link({local, Name}, ?MODULE, Options, []).
 
@@ -481,22 +481,22 @@ parse_rpc(#raft_identity{name = Name} = Self, ?LEGACY_RAFT_RPC(Procedure, Term,
 -spec commit(
     Server :: gen_statem:server_ref(),
     Op :: wa_raft_acceptor:op()
-) -> ok | wa_raft:error().
+) -> ok.
 commit(Server, Op) ->
     gen_statem:cast(Server, ?COMMIT_COMMAND(Op)).
 
 -spec read(
     Server :: gen_statem:server_ref(),
     Op :: wa_raft_acceptor:read_op()
-) -> ok | wa_raft:error().
+) -> ok.
 read(Server, Op) ->
     gen_statem:cast(Server, ?READ_COMMAND(Op)).
 
 -spec snapshot_available(
     Server :: gen_statem:server_ref(),
     Root :: file:filename(),
     Position :: wa_raft_log:log_pos()
-) -> ok | wa_raft:error().
+) -> ok | {error, Reason :: term()}.
 snapshot_available(Server, Root, Position) ->
     % Use the storage call timeout because this command requires the RAFT
     % server to make a potentially expensive call against the RAFT storage
@@ -507,7 +507,7 @@ snapshot_available(Server, Root, Position) ->
     Server :: gen_statem:server_ref(),
     Action :: add | remove | add_witness | remove_witness,
     Peer :: peer()
-) -> {ok, Position :: wa_raft_log:log_pos()} | wa_raft:error().
+) -> {ok, Position :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 adjust_membership(Server, Action, Peer) ->
     adjust_membership(Server, Action, Peer, undefined).
 
@@ -516,30 +516,30 @@ adjust_membership(Server, Action, Peer) ->
     Action :: add | remove | add_witness | remove_witness,
     Peer :: peer(),
     ConfigIndex :: wa_raft_log:log_index() | undefined
-) -> {ok, Position :: wa_raft_log:log_pos()} | wa_raft:error().
+) -> {ok, Position :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 adjust_membership(Server, Action, Peer, ConfigIndex) ->
     gen_statem:call(Server, ?ADJUST_MEMBERSHIP_COMMAND(Action, Peer, ConfigIndex), ?RAFT_RPC_CALL_TIMEOUT()).
 
 %% Request the specified RAFT server to start an election in the next term.
--spec trigger_election(Server :: gen_statem:server_ref()) -> ok | wa_raft:error().
+-spec trigger_election(Server :: gen_statem:server_ref()) -> ok | {error, Reason :: term()}.
 trigger_election(Server) ->
     trigger_election(Server, current).
 
 %% Request the specified RAFT server to trigger a new election in the term *after* the specified term.
--spec trigger_election(Server :: gen_statem:server_ref(), Term :: term_or_offset()) -> ok | wa_raft:error().
+-spec trigger_election(Server :: gen_statem:server_ref(), Term :: term_or_offset()) -> ok | {error, Reason :: term()}.
 trigger_election(Server, Term) ->
     gen_statem:call(Server, ?TRIGGER_ELECTION_COMMAND(Term), ?RAFT_RPC_CALL_TIMEOUT()).
 
 %% Request the specified RAFT server to promote itself to leader of the specified term.
--spec promote(Server :: gen_statem:server_ref(), Term :: term_or_offset()) -> ok | wa_raft:error().
+-spec promote(Server :: gen_statem:server_ref(), Term :: term_or_offset()) -> ok | {error, Reason :: term()}.
 promote(Server, Term) ->
     promote(Server, Term, false).
 
--spec promote(Server :: gen_statem:server_ref(), Term :: term_or_offset(), Force :: boolean()) -> ok | wa_raft:error().
+-spec promote(Server :: gen_statem:server_ref(), Term :: term_or_offset(), Force :: boolean()) -> ok | {error, Reason :: term()}.
 promote(Server, Term, Force) ->
     gen_statem:call(Server, ?PROMOTE_COMMAND(Term, Force), ?RAFT_RPC_CALL_TIMEOUT()).
 
--spec resign(Server :: gen_statem:server_ref()) -> ok | wa_raft:error().
+-spec resign(Server :: gen_statem:server_ref()) -> ok | {error, Reason :: term()}.
 resign(Server) ->
     gen_statem:call(Server, ?RESIGN_COMMAND, ?RAFT_RPC_CALL_TIMEOUT()).
 
@@ -551,11 +551,11 @@ handover(Server) ->
 %% Instruct a RAFT leader to attempt a handover to the specified peer node.
 %% If an `undefined` peer node is specified, then handover to a random handover candidate.
 %% Returns which peer node the handover was sent to or otherwise an error.
--spec handover(Server :: gen_statem:server_ref(), Peer :: node() | undefined) -> {ok, Peer :: node()} | wa_raft:error().
+-spec handover(Server :: gen_statem:server_ref(), Peer :: node() | undefined) -> {ok, Peer :: node()} | {error, Reason :: term()}.
 handover(Server, Peer) ->
     gen_statem:call(Server, ?HANDOVER_COMMAND(Peer), ?RAFT_RPC_CALL_TIMEOUT()).
 
--spec handover_candidates(Server :: gen_statem:server_ref()) -> {ok, Candidates :: [node()]} | wa_raft:error().
+-spec handover_candidates(Server :: gen_statem:server_ref()) -> {ok, Candidates :: [node()]} | {error, Reason :: term()}.
 handover_candidates(Server) ->
     gen_statem:call(Server, ?HANDOVER_CANDIDATES_COMMAND, ?RAFT_RPC_CALL_TIMEOUT()).
 
@@ -572,7 +572,7 @@ enable(Server) ->
     Position :: wa_raft_log:log_pos(),
     Config :: config(),
     Data :: dynamic()
-) -> ok | wa_raft:error().
+) -> ok | {error, Reason :: term()}.
 bootstrap(Server, Position, Config, Data) ->
     gen_statem:call(Server, ?BOOTSTRAP_COMMAND(Position, Config, Data), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
@@ -2984,13 +2984,17 @@ append_entries(
             % of the log.
             {ok, View1} = wa_raft_log:append(View0, NewEntries),
             {ok, true, PrevLogIndex + EntryCount, Data#raft_state{log_view = View1}};
-        {conflict, ConflictIndex, [{ConflictTerm, _} | _]} when ConflictIndex =< CommitIndex ->
+        {conflict, ConflictIndex, [ConflictEntry | _]} when ConflictIndex =< CommitIndex ->
             % A conflict is detected that would result in the truncation of a
             % log entry that the local replica has committed. We cannot validly
             % delete log entries that are already committed because doing so
             % may potenially cause the log entry to be no longer present on a
             % majority of replicas.
             {ok, LocalTerm} = wa_raft_log:term(View0, ConflictIndex),
+            {ConflictTerm, _} = if
+                is_binary(ConflictEntry) -> binary_to_term(ConflictEntry);
+                true -> ConflictEntry
+            end,
             ?RAFT_COUNT({raft, State, 'heartbeat.error.corruption.excessive_truncation'}),
             ?RAFT_LOG_WARNING(State, Data, "refuses heartbeat at ~0p to ~0p that requires truncation past ~0p (term ~0p vs ~0p) when log entries up to ~0p are already committed.",
                 [PrevLogIndex, PrevLogIndex + EntryCount, ConflictIndex, ConflictTerm, LocalTerm, CommitIndex]),
@@ -3021,7 +3025,7 @@ append_entries(
                         [ConflictIndex, PrevLogIndex, PrevLogIndex + EntryCount, Reason, 30]),
                     {ok, false, wa_raft_log:last_index(View0), Data}
             end;
-        {error, out_of_range} ->
+        {invalid, out_of_range} ->
             % If the heartbeat is out of range (generally past the end of the
             % log) then ignore and notify the leader of what log entry is
             % required by this replica.
@@ -3097,7 +3101,7 @@ request_vote_impl(State, Candidate, _, _,  #raft_state{voted_for = VotedFor} = D
 %%------------------------------------------------------------------------------
 
 %% Generic reply function for non-RPC requests that operates based on event type.
--spec reply(Type :: enter | gen_statem:event_type(), Message :: term()) -> ok | wa_raft:error().
+-spec reply(Type :: enter | gen_statem:event_type(), Message :: term()) -> ok | {error, Reason :: term()}.
 reply(cast, _) ->
     ok;
 reply({call, From}, Message) ->

src/wa_raft_server.erl

@@ -62,7 +62,6 @@
 -export_type([
     storage_handle/0,
     metadata/0,
-    error/0,
     status/0
 ]).
 
@@ -126,7 +125,7 @@
 %% Issue a read command to get the label associated with the most
 %% recent command that was applied with a label. See the optional
 %% callback `storage_apply/4` for details.
--callback storage_label(Handle :: storage_handle()) -> {ok, Label :: wa_raft_label:label()} | error().
+-callback storage_label(Handle :: storage_handle()) -> {ok, Label :: wa_raft_label:label()} | {error, Reason :: term()}.
 -optional_callbacks([storage_label/1]).
 
 
@@ -190,7 +189,7 @@
 %% If the command could not be applied in a manner so as to preserve the
 %% desired consistency guarantee then implementations can raise an error to be
 %% aborted safely.
--callback storage_apply_config(Config :: wa_raft_server:config(), Position :: wa_raft_log:log_pos(), Handle :: storage_handle()) -> {Result :: ok | error(), NewHandle :: storage_handle()}.
+-callback storage_apply_config(Config :: wa_raft_server:config(), Position :: wa_raft_log:log_pos(), Handle :: storage_handle()) -> {Result :: ok | {error, Reason :: term()}, NewHandle :: storage_handle()}.
 
 %%-----------------------------------------------------------------------------
 %% RAFT Storage Provider - Read Commands
@@ -233,14 +232,14 @@
 %% producing a directory tree rooted at the provided path that represents the
 %% current storage state. The produced snapshot should retain the current
 %% position when loaded.
--callback storage_create_snapshot(Path :: file:filename(), Handle :: storage_handle()) -> ok | error().
+-callback storage_create_snapshot(Path :: file:filename(), Handle :: storage_handle()) -> ok | {error, Reason :: term()}.
 
 %% Create a new witness snapshot at the provided path which must contain the current
 %% position in storage and configuration.
 %% The snapshot will be empty (without actual storage data) but will retain all
 %% necessary metadata. When loaded, this witness snapshot will reflect the exact
 %% position state of the original storage without the storage contents.
--callback storage_create_witness_snapshot(Path :: file:filename(), Handle :: storage_handle()) -> ok | error().
+-callback storage_create_witness_snapshot(Path :: file:filename(), Handle :: storage_handle()) -> ok | {error, Reason :: term()}.
 -optional_callback([storage_create_witness_snapshot/2]).
 
 %% Load a snapshot previously created by the same storage provider, possibly
@@ -249,7 +248,7 @@
 %% If a recoverable error occured, the storage state should remain unchanged.
 %% If the storage state is no longer suitable for use, an error should be
 %% raised.
--callback storage_open_snapshot(Path :: file:filename(), ExpectedPosition :: wa_raft_log:log_pos(), Handle :: storage_handle()) -> {ok, NewHandle :: storage_handle()} | error().
+-callback storage_open_snapshot(Path :: file:filename(), ExpectedPosition :: wa_raft_log:log_pos(), Handle :: storage_handle()) -> {ok, NewHandle :: storage_handle()} | {error, Reason :: term()}.
 
 %%-----------------------------------------------------------------------------
 %% RAFT Storage Provider - Bootstrapping
@@ -262,7 +261,7 @@
 %% version and the config as the value. Extra data may be used by implementors
 %% to provide extra state via arguments to external APIs that use this
 %% endpoint, such as the partition bootstrapping API.
--callback storage_make_empty_snapshot(Options :: #raft_options{}, Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: dynamic()) -> ok | error().
+-callback storage_make_empty_snapshot(Options :: #raft_options{}, Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: dynamic()) -> ok | {error, Reason :: term()}.
 -optional_callback([storage_make_empty_snapshot/5]).
 
 %%-----------------------------------------------------------------------------
@@ -271,7 +270,6 @@
 
 -type metadata() :: config | atom().
 -type storage_handle() :: dynamic().
--type error() :: {error, term()}.
 
 -type status() :: [status_element()].
 -type status_element() ::
@@ -381,11 +379,11 @@ status(Storage) ->
 position(Storage) ->
     gen_server:call(Storage, ?POSITION_REQUEST, ?RAFT_STORAGE_CALL_TIMEOUT()).
 
--spec label(Storage :: gen_server:server_ref()) -> {ok, Label :: wa_raft_label:label()} | wa_raft_storage:error().
+-spec label(Storage :: gen_server:server_ref()) -> {ok, Label :: wa_raft_label:label()} | {error, Reason :: term()}.
 label(Storage) ->
     gen_server:call(Storage, ?LABEL_REQUEST, ?RAFT_STORAGE_CALL_TIMEOUT()).
 
--spec config(Storage :: gen_server:server_ref()) -> {ok, wa_raft_log:log_pos(), wa_raft_server:config()} | undefined | wa_raft_storage:error().
+-spec config(Storage :: gen_server:server_ref()) -> {ok, wa_raft_log:log_pos(), wa_raft_server:config()} | undefined | {error, Reason :: term()}.
 config(Storage) ->
     gen_server:call(Storage, ?CONFIG_REQUEST, ?RAFT_STORAGE_CALL_TIMEOUT()).
 
@@ -418,39 +416,39 @@ apply(Storage, Record, Size, EffectiveTerm) ->
 apply_read(Storage, From, Command) ->
     gen_server:cast(Storage, ?APPLY_READ_REQUEST(From, Command)).
 
--spec open_snapshot(Storage :: gen_server:server_ref(), Path :: file:filename(), Position :: wa_raft_log:log_pos()) -> ok | error().
+-spec open_snapshot(Storage :: gen_server:server_ref(), Path :: file:filename(), Position :: wa_raft_log:log_pos()) -> ok | {error, Reason :: term()}.
 open_snapshot(Storage, Path, Position) ->
     gen_server:call(Storage, ?OPEN_SNAPSHOT_REQUEST(Path, Position), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
--spec create_snapshot(Storage :: gen_server:server_ref()) -> {ok, Pos :: wa_raft_log:log_pos()} | error().
+-spec create_snapshot(Storage :: gen_server:server_ref()) -> {ok, Pos :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 create_snapshot(Storage) ->
     gen_server:call(Storage, ?CREATE_SNAPSHOT_REQUEST(), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
 %% Be careful when using the same name for two snapshots as the RAFT storage
 %% server will not recreate an existing snapshot even if the storage state has
 %% advanced since the snapshot was created; however, this method will always
 %% return the current position upon success.
--spec create_snapshot(Storage :: gen_server:server_ref(), Name :: string()) -> {ok, Pos :: wa_raft_log:log_pos()} | error().
+-spec create_snapshot(Storage :: gen_server:server_ref(), Name :: string()) -> {ok, Pos :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 create_snapshot(Storage, Name) ->
     gen_server:call(Storage, ?CREATE_SNAPSHOT_REQUEST(Name), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
--spec create_witness_snapshot(Storage :: gen_server:server_ref()) -> {ok, Pos :: wa_raft_log:log_pos()} | error().
+-spec create_witness_snapshot(Storage :: gen_server:server_ref()) -> {ok, Pos :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 create_witness_snapshot(Storage) ->
     gen_server:call(Storage, ?CREATE_WITNESS_SNAPSHOT_REQUEST(), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
 %% Be careful when using the same name for two snapshots as the RAFT storage
 %% server will not recreate an existing snapshot even if the storage state has
 %% advanced since the snapshot was created; however, this method will always
 %% return the current position upon success.
--spec create_witness_snapshot(Storage :: gen_server:server_ref(), Name :: string()) -> {ok, Pos :: wa_raft_log:log_pos()} | error().
+-spec create_witness_snapshot(Storage :: gen_server:server_ref(), Name :: string()) -> {ok, Pos :: wa_raft_log:log_pos()} | {error, Reason :: term()}.
 create_witness_snapshot(Storage, Name) ->
     gen_server:call(Storage, ?CREATE_WITNESS_SNAPSHOT_REQUEST(Name), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
 -spec delete_snapshot(Storage :: gen_server:server_ref(), Name :: string()) -> ok.
 delete_snapshot(Storage, Name) ->
     gen_server:cast(Storage, ?DELETE_SNAPSHOT_REQUEST(Name)).
 
--spec make_empty_snapshot(Storage :: gen_server:server_ref(), Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: term()) -> ok | error().
+-spec make_empty_snapshot(Storage :: gen_server:server_ref(), Path :: file:filename(), Position :: wa_raft_log:log_pos(), Config :: wa_raft_server:config(), Data :: term()) -> ok | {error, Reason :: term()}.
 make_empty_snapshot(Storage, Path, Position, Config, Data) ->
     gen_server:call(Storage, ?MAKE_EMPTY_SNAPSHOT_REQUEST(Path, Position, Config, Data), ?RAFT_STORAGE_CALL_TIMEOUT()).
 
@@ -730,7 +728,7 @@ handle_delayed_reads(#state{queues = Queues, module = Module, handle = Handle, p
     ],
     ok.
 
--spec handle_create_snapshot(SnapshotName :: string(), Storage :: #state{}) -> {ok, wa_raft_log:log_pos()} | error().
+-spec handle_create_snapshot(SnapshotName :: string(), Storage :: #state{}) -> {ok, wa_raft_log:log_pos()} | {error, Reason :: term()}.
 handle_create_snapshot(SnapshotName, #state{name = Name, path = Path, module = Module, handle = Handle, position = Position} = State) ->
     SnapshotPath = filename:join(Path, SnapshotName),
     case filelib:is_dir(SnapshotPath) of
@@ -748,7 +746,7 @@ handle_create_snapshot(SnapshotName, #state{name = Name, path = Path, module = M
             end
     end.
 
--spec handle_create_witness_snapshot(SnapshotName :: string(), Storage :: #state{}) -> {ok, wa_raft_log:log_pos()} | error().
+-spec handle_create_witness_snapshot(SnapshotName :: string(), Storage :: #state{}) -> {ok, wa_raft_log:log_pos()} | {error, Reason :: term()}.
 handle_create_witness_snapshot(SnapshotName, #state{name = Name, path = Path, module = Module, handle = Handle, position = Position} = State) ->
     SnapshotPath = filename:join(Path, SnapshotName),
     case filelib:is_dir(SnapshotPath) of