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%% A remote manager is a gen_server for coordination of remotes for
%% all tokens.
%% Spawn one remote per configured p11p module per configured virtual
%% token. Provide a lookup service for servers that need a remote to
%% send a request to, by keeping track of which module is current for
%% a given vtoken.
-module(p11p_remote_manager).
-behaviour(gen_server).
%% API.
-export([start_link/0]).
-export([remote_for_token/1, client_change/2]). % For servers.
-export([server_change/2]). % For remotes.
%% Genserver callbacks.
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
%% Records and types.
-record(remote, {
tokname :: string(),
servid :: atom(),
modpath :: string(), % FIXME: filename
pid = undefined :: pid() | undefined
}).
-record(token, {
remotes :: [#remote{}], % Active remote in hd().
replay = <<>> :: binary()
}).
-record(state, {
tokens :: #{string() => #token{}}
}).
%% API implementation.
-spec start_link() -> {ok, pid()} | {error, term()}.
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
-spec remote_for_token(string()) -> pid().
remote_for_token(TokName) ->
gen_server:call(?MODULE, {remote_for_token, TokName}).
client_change(Change, Args) ->
gen_server:call(?MODULE, {client_change, Change, Args}).
server_change(Change, Args) ->
gen_server:call(?MODULE, {server_change, Change, Args}).
%% Genserver callbacks.
init([]) ->
{ok, #state{tokens = init_tokens(p11p_config:tokens())}}.
handle_call({remote_for_token, TokName}, _From, #state{tokens = Tokens} = State) ->
#{TokName := Token} = Tokens,
Remotes = Token#token.remotes,
#remote{tokname = TokName, servid = ServId, modpath = ModPath, pid = Pid} = Remote = hd(Remotes),
case Pid of
undefined ->
{ok, NewPid} = p11p_remote:start_link(ServId, TokName, ModPath),
NewRemote = Remote#remote{pid = NewPid},
NewToken = Token#token{remotes = [NewRemote | tl(Remotes)]},
NewState = State#state{tokens = Tokens#{TokName := NewToken}},
{reply, NewPid, NewState};
_ ->
{reply, Pid, State}
end;
handle_call({server_change, timeout, [TokName]}, _From, #state{tokens = Tokens} = State) ->
lager:debug("~p: ~s: timed out", [self(), TokName]),
%% TODO: do some code dedup with remote_for_token?
#{TokName := Token} = Tokens,
Remotes = Token#token.remotes,
Remote = hd(Remotes),
NewRemote = Remote#remote{pid = undefined},
NewToken = Token#token{remotes = tl(Remotes) ++ [NewRemote]},
NewState = State#state{tokens = Tokens#{TokName := NewToken}},
lager:debug("~p: ~s: updated token: ~p", [self(), TokName, NewToken]),
{reply, ok, NewState};
handle_call({client_change, client_gone, [TokName, Pid]}, From, #state{tokens = Tokens} = State) ->
lager:debug("~p: killing off remote ~p on request from ~p", [self(), Pid, From]),
gen_server:stop(Pid),
#{TokName := Token} = Tokens,
Remotes = Token#token.remotes,
NewRemotes = lists:map(fun(E) -> % TODO: any risk of losing list order?
case E#remote.pid of
Pid -> E#remote{pid = undefined};
_ -> E
end end, Remotes),
NewToken = Token#token{remotes = NewRemotes},
NewState = State#state{tokens = Tokens#{TokName := NewToken}},
{reply, ok, NewState};
handle_call(Call, _From, State) ->
lager:debug("Unhandled call: ~p~n", [Call]),
{reply, unhandled, State}.
handle_cast(Cast, State) ->
lager:debug("Unhandled cast: ~p~n", [Cast]),
{noreply, State}.
handle_info({Port, {exit_status, Status}}, State) ->
lager:info("~p: process exited with ~p", [Port, Status]),
{stop, child_exit, State};
handle_info(Info, State) ->
lager:debug("~p: Unhandled info: ~p~n", [self(), Info]),
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVersion, State, _Extra) ->
{ok, State}.
%% Private functions
-spec init_tokens([p11p_config:token()]) -> #{string() => #token{}}.
init_tokens(ConfTokens) ->
init_tokens(ConfTokens, #{}).
init_tokens([], Acc)->
lager:debug("~p: created tokens from config: ~p", [self(), Acc]),
Acc;
init_tokens([H|T], Acc)->
TokName = p11p_config:nameof(H),
init_tokens(T, Acc#{TokName => new_token(TokName, H)}).
new_token(TokName, ConfToken) ->
#token{remotes = remotes(TokName, p11p_config:modules_for_token(p11p_config:nameof(ConfToken)))}.
remotes(TokName, ConfModules) ->
remotes(TokName, ConfModules, []).
remotes(_, [], Acc) ->
Acc;
remotes(TokName, [H|T], Acc) ->
ModName = p11p_config:nameof(H),
ServName = "p11p_remote:" ++ TokName ++ ":" ++ ModName,
ModPath = p11p_config:module_path(H),
remotes(TokName, T, [#remote{
tokname = TokName,
servid = list_to_atom(ServName),
modpath = ModPath,
pid = undefined
} | Acc]).
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