/
riak_core_ring_manager.erl
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/
riak_core_ring_manager.erl
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%% -------------------------------------------------------------------
%%
%% riak_core: Core Riak Application
%%
%% 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
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%% KIND, either express or implied. See the License for the
%% specific language governing permissions and limitations
%% under the License.
%%
%% -------------------------------------------------------------------
%% @doc the local view of the cluster's ring configuration
-module(riak_core_ring_manager).
-include_lib("eunit/include/eunit.hrl").
-define(RING_KEY, riak_ring).
-behaviour(gen_server2).
-export([start_link/0,
start_link/1,
get_my_ring/0,
set_my_ring/1,
write_ringfile/0,
prune_ringfiles/0,
read_ringfile/1,
find_latest_ringfile/0,
do_write_ringfile/1,
ring_trans/2,
stop/0]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-ifdef(TEST).
-export([set_ring_global/1]).
-include_lib("eunit/include/eunit.hrl").
-endif.
%% ===================================================================
%% Public API
%% ===================================================================
start_link() ->
gen_server2:start_link({local, ?MODULE}, ?MODULE, [live], []).
%% Testing entry point
start_link(test) ->
gen_server2:start_link({local, ?MODULE}, ?MODULE, [test], []).
%% @spec get_my_ring() -> {ok, riak_core_ring:riak_core_ring()} | {error, Reason}
get_my_ring() ->
case mochiglobal:get(?RING_KEY) of
Ring when is_tuple(Ring) -> {ok, Ring};
undefined -> {error, no_ring}
end.
%% @spec set_my_ring(riak_core_ring:riak_core_ring()) -> ok
set_my_ring(Ring) ->
gen_server2:call(?MODULE, {set_my_ring, Ring}, infinity).
%% @spec write_ringfile() -> ok
write_ringfile() ->
gen_server2:cast(?MODULE, write_ringfile).
ring_trans(Fun, Args) ->
gen_server2:call(?MODULE, {ring_trans, Fun, Args}, infinity).
do_write_ringfile(Ring) ->
{{Year, Month, Day},{Hour, Minute, Second}} = calendar:universal_time(),
TS = io_lib:format(".~B~2.10.0B~2.10.0B~2.10.0B~2.10.0B~2.10.0B",
[Year, Month, Day, Hour, Minute, Second]),
case app_helper:get_env(riak_core, ring_state_dir) of
"<nostore>" -> nop;
Dir ->
Cluster = app_helper:get_env(riak_core, cluster_name),
FN = Dir ++ "/riak_core_ring." ++ Cluster ++ TS,
ok = filelib:ensure_dir(FN),
file:write_file(FN, term_to_binary(Ring))
end.
%% @spec find_latest_ringfile() -> string()
find_latest_ringfile() ->
Dir = app_helper:get_env(riak_core, ring_state_dir),
case file:list_dir(Dir) of
{ok, Filenames} ->
Cluster = app_helper:get_env(riak_core, cluster_name),
Timestamps = [list_to_integer(TS) || {"riak_core_ring", C1, TS} <-
[list_to_tuple(string:tokens(FN, ".")) || FN <- Filenames],
C1 =:= Cluster],
SortedTimestamps = lists:reverse(lists:sort(Timestamps)),
case SortedTimestamps of
[Latest | _] ->
{ok, Dir ++ "/riak_core_ring." ++ Cluster ++ "." ++ integer_to_list(Latest)};
_ ->
{error, not_found}
end;
{error, Reason} ->
{error, Reason}
end.
%% @spec read_ringfile(string()) -> riak_core_ring:riak_core_ring()
read_ringfile(RingFile) ->
{ok, Binary} = file:read_file(RingFile),
binary_to_term(Binary).
%% @spec prune_ringfiles() -> ok
prune_ringfiles() ->
case app_helper:get_env(riak_core, ring_state_dir) of
"<nostore>" -> ok;
Dir ->
Cluster = app_helper:get_env(riak_core, cluster_name),
case file:list_dir(Dir) of
{error,enoent} -> ok;
{ok, []} -> ok;
{ok, Filenames} ->
Timestamps = [TS || {"riak_core_ring", C1, TS} <-
[list_to_tuple(string:tokens(FN, ".")) || FN <- Filenames],
C1 =:= Cluster],
if Timestamps /= [] ->
%% there are existing ring files
TSPat = [io_lib:fread("~4d~2d~2d~2d~2d~2d",TS) ||
TS <- Timestamps],
TSL = lists:reverse(lists:sort([TS ||
{ok,TS,[]} <- TSPat])),
Keep = prune_list(TSL),
KeepTSs = [lists:flatten(
io_lib:format(
"~B~2.10.0B~2.10.0B~2.10.0B~2.10.0B~2.10.0B",K))
|| K <- Keep],
DelFNs = [Dir ++ "/" ++ FN || FN <- Filenames,
lists:all(fun(TS) ->
string:str(FN,TS)=:=0
end, KeepTSs)],
[file:delete(DelFN) || DelFN <- DelFNs],
ok;
true ->
%% directory wasn't empty, but there are no ring
%% files in it
ok
end
end
end.
%% @private (only used for test instances)
stop() ->
gen_server2:cast(?MODULE, stop).
%% ===================================================================
%% gen_server callbacks
%% ===================================================================
init([Mode]) ->
case Mode of
live ->
Ring = riak_core_ring:fresh();
test ->
Ring = riak_core_ring:fresh(16,node())
end,
mochiglobal:put(?RING_KEY, Ring),
% Initial notification to local observers that ring has changed
riak_core_ring_events:ring_update(Ring),
{ok, Mode}.
handle_call({set_my_ring, Ring}, _From, State) ->
set_ring_global(Ring),
% Notify any local observers that the ring has changed (async)
riak_core_ring_events:ring_update(Ring),
{reply,ok,State};
handle_call({ring_trans, Fun, Args}, _From, State) ->
{ok, Ring} = get_my_ring(),
case catch Fun(Ring, Args) of
{new_ring, NewRing} ->
mochiglobal:put(?RING_KEY, NewRing),
case riak_core_ring:random_other_node(NewRing) of
no_node ->
ignore;
Node ->
riak_core_gossip:send_ring(Node)
end,
riak_core_ring_events:ring_update(NewRing),
{reply, {ok, NewRing}, State};
ignore ->
{reply, not_changed, State};
Other ->
error_logger:error_msg("ring_trans: invalid return value: ~p~n",
[Other]),
{reply, not_changed, State}
end.
handle_cast(stop, State) ->
{stop,normal,State};
handle_cast(write_ringfile, test) ->
{noreply,test};
handle_cast(write_ringfile, State) ->
{ok, Ring} = get_my_ring(),
do_write_ringfile(Ring),
{noreply,State}.
handle_info(_Info, State) ->
{noreply, State}.
%% @private
terminate(_Reason, _State) ->
ok.
%% @private
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%% ===================================================================
%% Internal functions
%% ===================================================================
prune_list([X|Rest]) ->
lists:usort(lists:append([[X],back(1,X,Rest),back(2,X,Rest),
back(3,X,Rest),back(4,X,Rest),back(5,X,Rest)])).
back(_N,_X,[]) -> [];
back(N,X,[H|T]) ->
case lists:nth(N,X) =:= lists:nth(N,H) of
true -> back(N,X,T);
false -> [H]
end.
%% Set the ring in mochiglobal. Exported during unit testing
%% to make test setup simpler - no need to spin up a riak_core_ring_manager
%% process.
set_ring_global(Ring) ->
mochiglobal:put(?RING_KEY, Ring).