machi/test/machi_partition_simulator.erl

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%% -------------------------------------------------------------------
%%
%% Machi: a small village of replicated files
%%
%% Copyright (c) 2014 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.
%%
%% -------------------------------------------------------------------
-module(machi_partition_simulator).
-behaviour(gen_server).
-ifdef(TEST).
-ifdef(EQC).
-include_lib("eqc/include/eqc.hrl").
-endif.
-ifdef(PULSE).
-compile({parse_transform, pulse_instrument}).
-endif.
-export([start_link/3, stop/0,
get/1, reset_thresholds/2, set_seed/1,
no_partitions/0, always_last_partitions/0, always_these_partitions/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([islands2partitions/1,
partition2connection/2,
connection2partition/2,
partitions2num_islands/2,
partition_list_is_symmetric_p/2]).
-define(TAB, ?MODULE).
-record(state, {
seed,
old_partitions,
old_threshold,
no_partition_threshold,
method=oneway_partitions :: 'island' | 'oneway_partitions'
}).
start_link(Seed, OldThreshold, NoPartitionThreshold) ->
gen_server:start_link({local, ?MODULE}, ?MODULE,
{Seed, OldThreshold, NoPartitionThreshold}, []).
stop() ->
gen_server:call(?MODULE, {stop}, infinity).
get(Nodes) ->
gen_server:call(?MODULE, {get, Nodes}, infinity).
reset_thresholds(OldThreshold, NoPartitionThreshold) ->
gen_server:call(?MODULE, {reset_thresholds, OldThreshold, NoPartitionThreshold}, infinity).
set_seed(Seed) ->
gen_server:call(?MODULE, {set_seed, Seed}, infinity).
no_partitions() ->
reset_thresholds(-999, 999).
always_last_partitions() ->
reset_thresholds(999, 0).
always_these_partitions(Parts) ->
reset_thresholds(999, 0),
gen_server:call(?MODULE, {always_these_partitions, Parts}, infinity).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
init({Seed, OldThreshold, NoPartitionThreshold}) ->
{ok, #state{seed=Seed,
old_partitions={[],[[]]},
old_threshold=OldThreshold,
no_partition_threshold=NoPartitionThreshold}}.
handle_call({get, Nodes}, _From, S) ->
{Seed2, Partitions} =
calc_network_partitions(S#state.method,
Nodes,
S#state.seed,
S#state.old_partitions,
S#state.old_threshold,
S#state.no_partition_threshold),
{reply, Partitions, S#state{seed=Seed2,
old_partitions=Partitions}};
handle_call({reset_thresholds, OldThreshold, NoPartitionThreshold}, _From, S) ->
{reply, ok, S#state{old_threshold=OldThreshold,
no_partition_threshold=NoPartitionThreshold}};
handle_call({set_seed, Seed}, _From, S) ->
{reply, ok, S#state{seed=Seed}};
handle_call({always_these_partitions, Parts}, _From, S) ->
{reply, ok, S#state{old_partitions={Parts,[na_reset_by_always]}}};
handle_call({stop}, _From, S) ->
{stop, normal, ok, S}.
handle_cast(_Cast, S) ->
{noreply, S}.
handle_info(_Info, S) ->
{noreply, S}.
terminate(_Reason, _S) ->
ok.
code_change(_OldVsn, S, _Extra) ->
{ok, S}.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
calc_network_partitions(Method, Nodes, Seed1, OldPartition,
OldThreshold, NoPartitionThreshold) ->
{Cutoff2, Seed2} = random:uniform_s(100, Seed1),
if Cutoff2 < OldThreshold ->
{Seed2, OldPartition};
true ->
{Cutoff3, Seed3} = random:uniform_s(100, Seed1),
if Cutoff3 < NoPartitionThreshold ->
{Seed3, {[], [Nodes]}};
true ->
make_network_partition_locations(Method, Nodes, Seed3)
end
end.
make_network_partition_locations(island=_Method, Nodes, Seed1) ->
Num = length(Nodes),
{Seed2, WeightsNodes} = lists:foldl(
fun(Node, {Seeda, Acc}) ->
{Cutoff0, Seedb} =
random:uniform_s(100, Seeda),
Cutoff = erlang:max(
2, if Cutoff0 rem 4 == 0 ->
0;
true ->
Cutoff0
end),
{Seedb, [{Cutoff, Node}|Acc]}
end, {Seed1, []}, Nodes),
IslandSep = 100 div Num,
Islands = [
lists:sort([Nd || {Weight, Nd} <- WeightsNodes,
(Max - IslandSep) =< Weight, Weight < Max])
|| Max <- lists:seq(IslandSep + 1, 105, IslandSep)],
{Seed2, {lists:usort(islands2partitions(Islands)), lists:sort(Islands)}};
make_network_partition_locations(oneway_partitions=_Method, Nodes, Seed1) ->
Pairs = make_all_pairs(Nodes),
Num = length(Pairs),
{Seed2, Weights} = lists:foldl(
fun(_, {Seeda, Acc}) ->
{Cutoff, Seedb} = random:uniform_s(100, Seeda),
{Seedb, [Cutoff|Acc]}
end, {Seed1, []}, lists:seq(1, Num)),
{Cutoff3, Seed3} = random:uniform_s(100, Seed2),
{Seed3, {[X || {Weight, X} <- lists:zip(Weights, Pairs),
Weight < Cutoff3], [islands_not_supported]}}.
make_all_pairs(L) ->
lists:flatten(make_all_pairs2(lists:usort(L))).
make_all_pairs2([]) ->
[];
make_all_pairs2([_]) ->
[];
make_all_pairs2([H1|T]) ->
[[{H1, X}, {X, H1}] || X <- T] ++ make_all_pairs(T).
islands2partitions([]) ->
[];
islands2partitions([Island|Rest]) ->
[{X,Y} || X <- Island,
Y <- lists:append(Rest), X /= Y]
++
[{Y,X} || X <- Island,
Y <- lists:append(Rest), X /= Y]
++
islands2partitions(Rest).
partition2connection(Members0, Partition0) ->
p2c_invert(lists:usort(Members0), lists:usort(Partition0)).
connection2partition(Members0, Partition0) ->
p2c_invert(lists:usort(Members0), lists:usort(Partition0)).
p2c_invert(Members, Partition_list_Or_Connection_list) ->
All = [{X,Y} || X <- Members, Y <- Members, X /= Y],
All -- Partition_list_Or_Connection_list.
partitions2num_islands(Members0, Partition0) ->
%% Ignore duplicates in either arg, if any.
Members = lists:usort(Members0),
Partition = lists:usort(Partition0),
Connections = partition2connection(Members, Partition),
Cs = [lists:member({X,Y}, Connections)
orelse
lists:member({Y,X}, Connections) || X <- Members, Y <- Members,
X /= Y],
case lists:usort(Cs) of
[true] -> 1;
2015-04-10 02:08:17 +00:00
[false] -> many;
[false, true] -> many % TODO too lazy to finish
end.
partition_list_is_symmetric_p(Members0, Partition0) ->
%% %% Ignore duplicates in either arg, if any.
Members = lists:usort(Members0),
NumMembers = length(Members),
Partition = lists:usort(Partition0),
NewDict = lists:foldl(
fun({A,B}, Dict) ->
Key = if A > B -> {A,B};
true -> {B,A}
end,
orddict:update_counter(Key, 1, Dict)
end, orddict:new(), Partition),
AllOddP = orddict:fold(
fun(_Key, Count, true) when Count rem 2 == 0 ->
true;
(_, _, _) ->
false
end, true, NewDict),
if not AllOddP ->
false;
true ->
TwosCount = [Key || {Key, Count} <- orddict:to_list(NewDict),
Count == 2],
length(TwosCount) >= (NumMembers - 1)
end.
-endif. % TEST