dang, large commit.

 * node removed from #mem{}
 * start_gossip api call added
 * some dialyzer specs
 * 'new' join accepts PingNode, calls into cluster itself
 * get_test convenience method
 * don't save state when testing

include/common.hrl

@@ -42,7 +42,6 @@
 
 %% version 3 of membership state
 -record(mem, {header=3,
-              node,
               nodes=[],
               clock=[],
               args

src/mem3.erl

@@ -20,13 +20,13 @@
 
 %% API
 -export([start_link/0, start_link/1, stop/0, stop/1, reset/0]).
--export([join/2, clock/0, state/0]).
+-export([join/3, clock/0, state/0, start_gossip/0]).
 -export([partitions/0, fullmap/0]).
 -export([nodes/0, nodes_for_part/1, nodes_for_part/2, all_nodes_parts/1]).
 -export([parts_for_node/1]).
 
 %% for testing more than anything else
--export([merge_nodes/2]).
+-export([merge_nodes/2, next_up_node/1, next_up_node/3]).
 
 %% gen_server callbacks
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
@@ -46,9 +46,11 @@
 -type options() :: list().
 -type mem_node() :: {join_order(), node(), options()}.
 -type mem_node_list() :: [mem_node()].
--type arg_options() :: {test, boolean()} | {config, #config{}}.
+-type config() :: #config{}.
+-type arg_options() :: {test, boolean()} | {config, config()}.
 -type args() :: [] | [arg_options()].
 -type mem_state() :: #mem{}.
+-type test() :: undefined | node().
 -type epoch() :: float().
 -type clock() :: {node(), epoch()}.
 -type vector_clock() :: [clock()].
@@ -77,9 +79,9 @@ stop(Server) ->
     gen_server:cast(Server, stop).
 
 
--spec join(join_type(), mem_node_list()) -> ok.
-join(JoinType, Nodes) ->
-    gen_server:call(?SERVER, {join, JoinType, Nodes}).
+-spec join(join_type(), mem_node_list(), node() | nil) -> ok.
+join(JoinType, Nodes, PingNode) ->
+    gen_server:call(?SERVER, {join, JoinType, Nodes, PingNode}).
 
 
 -spec clock() -> vector_clock().
@@ -92,6 +94,11 @@ state() ->
     gen_server:call(?SERVER, state).
 
 
+-spec start_gossip() -> ok.
+start_gossip() ->
+    gen_server:call(?SERVER, start_gossip).
+
+
 -spec reset() -> ok | not_reset.
 reset() ->
     gen_server:call(?SERVER, reset).
@@ -156,7 +163,7 @@ all_nodes_parts(true) ->
 init(Args) ->
     process_flag(trap_exit,true),
     Config = get_config(Args),
-    Test = proplists:get_value(test, Args),
+    Test = get_test(Args),
     OldState = read_latest_state_file(Test, Config),
     showroom_log:message(info, "membership: membership server starting...", []),
     net_kernel:monitor_nodes(true),
@@ -165,9 +172,11 @@ init(Args) ->
 
 
 %% new node(s) joining to this node
-handle_call({join, JoinType, ExtNodes}, _From, State) ->
+handle_call({join, JoinType, ExtNodes, PingNode}, _From, State) ->
+    % NewState = handle_join(JoinType, ExtNodes, PingNode, State),
+    % {reply, ok, NewState};
     try
-        NewState = handle_join(JoinType, ExtNodes, State),
+        NewState = handle_join(JoinType, ExtNodes, PingNode, State),
         {reply, ok, NewState}
     catch _:Error ->
         showroom_log:message(error, "~p", [Error]),
@@ -184,7 +193,7 @@ handle_call(state, _From, State) ->
 
 %% reset - but only if we're in test mode
 handle_call(reset, _From, #mem{args=Args} = State) ->
-    Test = proplists:get_value(test, Args),
+    Test = get_test(Args),
     case Test of
     undefined -> {reply, not_reset, State};
     _ -> {reply, ok, int_reset(Test, State)}
@@ -196,11 +205,16 @@ handle_call(nodes, _From, #mem{nodes=Nodes} = State) ->
     {reply, {ok, NodeList}, State};
 
 %% gossip
-handle_call({gossip, #mem{node=RemoteNode} = RemoteState}, From, LocalState) ->
+handle_call({gossip, RemoteState}, {Pid,_Tag} = From, LocalState) ->
     showroom_log:message(info, "membership: received gossip from ~p",
-        [RemoteNode]),
+                         [erlang:node(Pid)]),
     handle_gossip(From, RemoteState, LocalState);
 
+% start_gossip
+handle_call(start_gossip, _From, State) ->
+    NewState = gossip(State),
+    {reply, ok, NewState};
+
 %% ignored call
 handle_call(Msg, _From, State) ->
     showroom_log:message(info, "membership: ignored call: ~p", [Msg]),
@@ -259,6 +273,10 @@ get_config(Args) ->
     end.
 
 
+get_test(Args) ->
+    proplists:get_value(test, Args).
+
+
 % we could be automatically:
 %  1. rejoining a cluster after some downtime
 %
@@ -277,7 +295,7 @@ handle_init(_Test, #mem{nodes=Nodes, args=Args} = OldState) ->
     {_, NodeList, _} = lists:unzip3(Nodes),
     ping_all_yall(NodeList),
     {RemoteStates, _BadNodes} = get_remote_states(NodeList),
-    Test = proplists:get_value(test, Args),
+    Test = get_test(Args),
     case compare_state_with_rest(OldState, RemoteStates) of
     match ->
         showroom_log:message(info, "membership: rejoined successfully", []),
@@ -289,32 +307,43 @@ handle_init(_Test, #mem{nodes=Nodes, args=Args} = OldState) ->
 
 
 %% handle join activities, return NewState
-handle_join(first, ExtNodes, State) ->
+handle_join(first, ExtNodes, nil, State) ->
     {_,Nodes,_} = lists:unzip3(ExtNodes),
     ping_all_yall(Nodes),
     int_join(ExtNodes, State);
 
-handle_join(new, ExtNodes, State) ->
-    {_,Nodes,_} = lists:unzip3(ExtNodes),
-    ping_all_yall(Nodes),
-    int_join(ExtNodes, State);
+handle_join(new, ExtNodes, PingNode, #mem{args=Args} = State) ->
+    NewState = case get_test(Args) of
+    undefined ->
+        % ping the PingNode and get its state
+        pong = net_adm:ping(PingNode),
+        timer:sleep(1000), % let dist. erl get set up... sigh.
+        {ok, RemoteState} = rpc:call(PingNode, mem3, state, []),
+        RemoteState;
+    _ ->
+        % testing, so meh
+        State
+    end,
+    % now use this info to join the ring
+    int_join(ExtNodes, NewState);
 
-handle_join(replace, [_OldNode | _], _State) ->
+handle_join(replace, [_OldNode | _], _PingNode, _State) ->
     % TODO implement me
     ok;
 
-handle_join(JoinType, _, _) ->
-    showroom_log:message(info, "membership: unknown join type: ~p", [JoinType]),
+handle_join(JoinType, _, PingNode, _) ->
+    showroom_log:message(info, "membership: unknown join type: ~p "
+                         "for ping node: ~p", [JoinType, PingNode]),
     {error, {unknown_join_type, JoinType}}.
 
 
-int_join(ExtNodes, #mem{node=Node, nodes=Nodes, clock=Clock} = State) ->
+int_join(ExtNodes, #mem{nodes=Nodes, clock=Clock} = State) ->
     NewNodes = lists:foldl(fun({Pos, N, _Options}=New, AccIn) ->
         check_pos(Pos, N, Nodes),
         [New|AccIn]
     end, Nodes, ExtNodes),
     NewNodes1 = lists:sort(NewNodes),
-    NewClock = vector_clock:increment(Node, Clock),
+    NewClock = vector_clock:increment(node(), Clock),
     NewState = State#mem{nodes=NewNodes1, clock=NewClock},
     install_new_state(NewState),
     NewState.
@@ -333,7 +362,7 @@ handle_gossip(From, RemoteState=#mem{clock=RemoteClock},
     greater ->
         % local node needs updating
         gen_server:reply(From, ok), % reply to sender first
-        install_new_state(RemoteState);
+        {noreply, install_new_state(RemoteState)};
     concurrent ->
         % ick, so let's resolve and merge states
         showroom_log:message(info,
@@ -342,7 +371,7 @@ handle_gossip(From, RemoteState=#mem{clock=RemoteClock},
             , [RemoteState, LocalState]),
         MergedState = merge_states(RemoteState, LocalState),
         gen_server:reply(From, {new_state, MergedState}), % reply to sender
-        install_new_state(MergedState)
+        {noreply, install_new_state(MergedState)}
     end.
 
 
@@ -367,18 +396,19 @@ merge_nodes(Remote, Local) ->
 
 
 gossip(#mem{args=Args} = NewState) ->
-    Test = proplists:get_value(test, Args),
+    Test = get_test(Args),
     gossip(Test, NewState).
 
 
-gossip(undefined, #mem{node=Node, nodes=StateNodes} = State) ->
+-spec gossip(test(), mem_state()) -> mem_state().
+gossip(undefined, #mem{nodes=StateNodes} = State) ->
     {_, Nodes, _} = lists:unzip3(StateNodes),
-    TargetNode = next_up_node(Node, Nodes),
+    TargetNode = next_up_node(Nodes),
     showroom_log:message(info, "membership: firing gossip from ~p to ~p",
-        [Node, TargetNode]),
+        [node(), TargetNode]),
     case gen_server:call({?SERVER, TargetNode}, {gossip, State}) of
-    ok -> ok;
-    {new_state, _NewState} -> ?debugHere,ok;
+    ok -> State;
+    {new_state, NewState} -> NewState;
     Error -> throw({unknown_gossip_response, Error})
     end;
 
@@ -387,11 +417,19 @@ gossip(_,_) ->
     ok.
 
 
-next_up_node(Node, Nodes) ->
+next_up_node(Nodes) ->
+    Node = node(),
+    next_up_node(Node, Nodes, up_nodes()).
+
+
+next_up_node(Node, Nodes, UpNodes) ->
     {A, [Node|B]} = lists:splitwith(fun(N) -> N /= Node end, Nodes),
-    List = lists:append([B, A, [Node]]),
-    UpNodes = lists:delete(fun(N) -> lists:member(N, up_nodes()) end, List),
-    hd(UpNodes). % TODO: empty list?
+    List = lists:append(B, A), % be sure to eliminate Node
+    DownNodes = Nodes -- UpNodes,
+    case List -- DownNodes of
+    [Target|_] -> Target;
+    [] -> throw({error, no_gossip_targets_available})
+    end.
 
 
 up_nodes() ->
@@ -425,8 +463,7 @@ read_latest_state_file(undefined, Config) ->
         {ok, File} = find_latest_state_filename(Config),
         case file:consult(File) of
         {ok, [#mem{}=State]} -> State;
-        Else ->
-                ?debugFmt("~nElse: ~p~n", [Else]),
+        _Else ->
                 throw({error, bad_mem_state_file})
         end
     catch _:Error ->
@@ -439,13 +476,15 @@ read_latest_state_file(_, _) ->
 
 install_new_state(#mem{args=Args} = State) ->
     Config = get_config(Args),
-    save_state_file(State, Config),
+    Test = get_test(Args),
+    save_state_file(Test, State, Config),
     gossip(State).
 
 
 %% @doc save the state file to disk, with current timestamp.
 %%      thx to riak_ring_manager:do_write_ringfile/1
-save_state_file(State, Config) ->
+-spec save_state_file(test(), mem_state(), config()) -> ok.
+save_state_file(undefined, State, Config) ->
     Dir = Config#config.directory,
     {{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",
@@ -454,7 +493,9 @@ save_state_file(State, Config) ->
     ok = filelib:ensure_dir(FN),
     {ok, File} = file:open(FN, [binary, write]),
     io:format(File, "~w.~n", [State]),
-    file:close(File).
+    file:close(File);
+
+save_state_file(_,_,_) -> ok. % don't save if testing
 
 
 check_pos(Pos, Node, Nodes) ->
@@ -476,12 +517,8 @@ int_reset(Test) ->
     int_reset(Test, #mem{}).
 
 
-int_reset(Test, State) ->
-    Node = case Test of
-    undefined -> node();
-    _ -> Test
-    end,
-    State#mem{node=Node, nodes=[], clock=[]}.
+int_reset(_Test, State) ->
+    State#mem{nodes=[], clock=[]}.
 
 
 ping_all_yall(Nodes) ->
@@ -492,18 +529,19 @@ get_remote_states(NodeList) ->
     NodeList1 = lists:delete(node(), NodeList),
     {States1, BadNodes} = rpc:multicall(NodeList1, mem3, state, [], 5000),
     {_Status, States2} = lists:unzip(States1),
-    {States2, BadNodes}.
+    {lists:zip(NodeList1,States2), BadNodes}.
 
 
 %% @doc compare state with states based on vector clock
 %%      return match | {bad_state_match, Node, NodesThatDontMatch}
-compare_state_with_rest(#mem{node=Node, clock=Clock} = _State, States) ->
-    Results = lists:map(fun(#mem{node=Node1, clock=Clock1}) ->
-        {vector_clock:equals(Clock, Clock1), Node1}
+compare_state_with_rest(#mem{clock=Clock} = _State, States) ->
+    Results = lists:map(fun({Node, #mem{clock=Clock1}}) ->
+        {vector_clock:equals(Clock, Clock1), Node}
     end, States),
     BadResults = lists:foldl(fun({true, _N}, AccIn) -> AccIn;
-        ({false, N}, AccIn) -> [N | AccIn] end, [], Results),
+                                ({false, N}, AccIn) -> [N | AccIn]
+    end, [], Results),
     if
     length(BadResults) == 0 -> match;
-    true -> {bad_state_match, Node, BadResults}
+    true -> {bad_state_match, node(), BadResults}
     end.