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%% -------------------------------------------------------------------
%% riak_vnode_master: dispatch to vnodes
%% Copyright (c) 2007-2010 Basho Technologies, Inc. All Rights Reserved.
%% This file is provided to you under the Apache License,
%% Version 2.0 (the "License"); you may not use this file
%% except in compliance with the License. You may obtain
%% a copy of the License at
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% KIND, either express or implied. See the License for the
%% specific language governing permissions and limitations
%% under the License.
%% -------------------------------------------------------------------
%% @doc dispatch to vnodes
-export([start_link/1, start_link/2, get_vnode_pid/2,
start_vnode/2, command/3, command/4, sync_command/3,
sync_spawn_command/3, make_request/3,
all_nodes/1, reg_name/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(idxrec, {idx, pid, monref}).
-record(state, {idxtab, excl=ordsets:new(), sup_name, vnode_mod, legacy}).
-define(DEFAULT_TIMEOUT, 5000).
make_name(VNodeMod,Suffix) -> list_to_atom(atom_to_list(VNodeMod)++Suffix).
reg_name(VNodeMod) -> make_name(VNodeMod, "_master").
start_link(VNodeMod) ->
start_link(VNodeMod, undefined).
start_link(VNodeMod, LegacyMod) ->
RegName = reg_name(VNodeMod),
gen_server:start_link({local, RegName}, ?MODULE,
[VNodeMod,LegacyMod,RegName], []).
start_vnode(Index, VNodeMod) ->
RegName = reg_name(VNodeMod),
gen_server:cast(RegName, {Index, start_vnode}).
get_vnode_pid(Index, VNodeMod) ->
RegName = reg_name(VNodeMod),
gen_server:call(RegName, {Index, get_vnode}, infinity).
command(Preflist, Msg, VMaster) ->
command(Preflist, Msg, noreply, VMaster).
%% Send the command to the preflist given with responses going to Sender
command([], _Msg, _Sender, _VMaster) ->
command([{Index,Node}|Rest], Msg, Sender, VMaster) ->
gen_server:cast({VMaster, Node}, make_request(Msg, Sender, Index)),
command(Rest, Msg, Sender, VMaster);
%% Send the command to an individual Index/Node combination
command({Index,Node}, Msg, Sender, VMaster) ->
gen_server:cast({VMaster, Node}, make_request(Msg, Sender, Index)).
%% Send a synchronous command to an individual Index/Node combination.
%% Will not return until the vnode has returned
sync_command(IndexNode, Msg, VMaster) ->
sync_command(IndexNode, Msg, VMaster, ?DEFAULT_TIMEOUT).
sync_command({Index,Node}, Msg, VMaster, Timeout) ->
%% Issue the call to the master, it will update the Sender with
%% the From for handle_call so that the {reply} return gets
%% sent here.
gen_server:call({VMaster, Node},
make_request(Msg, {server, undefined, undefined}, Index), Timeout).
%% Send a synchronous spawned command to an individual Index/Node combination.
%% Will not return until the vnode has returned, but the vnode_master will
%% continue to handle requests.
sync_spawn_command({Index,Node}, Msg, VMaster) ->
gen_server:call({VMaster, Node},
{spawn, make_request(Msg, {server, undefined, undefined}, Index)},
%% Make a request record - exported for use by legacy modules
-spec make_request(vnode_req(), sender(), partition()) -> #riak_vnode_req_v1{}.
make_request(Request, Sender, Index) ->
%% Request a list of Pids for all vnodes
all_nodes(VNodeMod) ->
RegName = reg_name(VNodeMod),
gen_server:call(RegName, all_nodes, infinity).
%% @private
init([VNodeMod, LegacyMod, RegName]) ->
%% Get the current list of vnodes running in the supervisor. We use this
%% to rebuild our ETS table for routing messages to the appropriate
%% vnode.
VnodePids = [Pid || {_, Pid, worker, _}
<- supervisor:which_children(riak_core_vnode_sup)],
IdxTable = ets:new(RegName, [{keypos, 2}]),
%% In case this the vnode master is being restarted, scan the existing
%% vnode children and work out which module and index they are responsible
%% for. During startup it is possible that these vnodes may be shutting
%% down as we check them if there are several types of vnodes active.
PidIdxs = lists:flatten(
[{Pid, riak_core_vnode:get_mod_index(Pid)}]
_:_Err ->
end || Pid <- VnodePids]),
%% Populate the ETS table with processes running this VNodeMod (filtered
%% in the list comprehension)
F = fun(Pid, Idx) ->
Mref = erlang:monitor(process, Pid),
#idxrec { idx = Idx, pid = Pid, monref = Mref }
IdxRecs = [F(Pid, Idx) || {Pid, {Mod, Idx}} <- PidIdxs, Mod =:= VNodeMod],
true = ets:insert_new(IdxTable, IdxRecs),
{ok, #state{idxtab=IdxTable,
handle_cast({Partition, start_vnode}, State=#state{excl=Excl}) ->
get_vnode(Partition, State),
{noreply, State#state{excl=ordsets:del_element(Partition, Excl)}};
handle_cast(Req=?VNODE_REQ{index=Idx}, State) ->
Pid = get_vnode(Idx, State),
gen_fsm:send_event(Pid, Req),
{noreply, State};
handle_cast(Other, State=#state{legacy=Legacy}) when Legacy =/= undefined ->
case catch Legacy:rewrite_cast(Other) of
{ok, ?VNODE_REQ{}=Req} ->
handle_cast(Req, State);
_ ->
{noreply, State}
handle_call(Req=?VNODE_REQ{index=Idx, sender={server, undefined, undefined}}, From, State) ->
Pid = get_vnode(Idx, State),
gen_fsm:send_event(Pid, Req?VNODE_REQ{sender={server, undefined, From}}),
{noreply, State};
Req=?VNODE_REQ{index=Idx, sender={server, undefined, undefined}}}, From, State) ->
Pid = get_vnode(Idx, State),
Sender = {server, undefined, From},
fun() -> gen_fsm:send_all_state_event(Pid, Req?VNODE_REQ{sender=Sender}) end),
{noreply, State};
handle_call(all_nodes, _From, State) ->
{reply, lists:flatten(ets:match(State#state.idxtab, {idxrec, '_', '$1', '_'})), State};
handle_call({Partition, get_vnode}, _From, State) ->
Pid = get_vnode(Partition, State),
{reply, {ok, Pid}, State};
handle_call(Other, From, State=#state{legacy=Legacy}) when Legacy =/= undefined ->
case catch Legacy:rewrite_call(Other, From) of
{ok, ?VNODE_REQ{}=Req} ->
handle_call(Req, From, State);
_ ->
{noreply, State}
handle_info({'DOWN', MonRef, process, _P, _I}, State) ->
delmon(MonRef, State),
{noreply, State}.
%% @private
terminate(_Reason, _State) ->
%% @private
code_change(_OldVsn, State, _Extra) -> {ok, State}.
%% @private
idx2vnode(Idx, _State=#state{idxtab=T}) ->
case ets:match(T, {idxrec, Idx, '$1', '_'}) of
[[VNodePid]] -> VNodePid;
[] -> no_match
%% @private
delmon(MonRef, _State=#state{idxtab=T}) ->
ets:match_delete(T, {idxrec, '_', '_', MonRef}).
%% @private
add_vnode_rec(I, _State=#state{idxtab=T}) -> ets:insert(T,I).
%% @private
get_vnode(Idx, State=#state{vnode_mod=Mod}) ->
case idx2vnode(Idx, State) of
no_match ->
{ok, Pid} = riak_core_vnode_sup:start_vnode(Mod, Idx),
MonRef = erlang:monitor(process, Pid),
add_vnode_rec(#idxrec{idx=Idx,pid=Pid,monref=MonRef}, State),
X -> X
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