%% This file is a copy of supervisor.erl from the R13B-3 Erlang/OTP %% distribution, with the following modifications: %% %% 1) the module name is supervisor2 %% %% 2) there is a new strategy called %% simple_one_for_one_terminate. This is exactly the same as for %% simple_one_for_one, except that children *are* explicitly %% terminated as per the shutdown component of the child_spec. %% %% 3) child specifications can contain, as the restart type, a tuple %% {permanent, Delay} | {transient, Delay} | {intrinsic, Delay} %% where Delay >= 0 (see point (4) below for intrinsic). The delay, %% in seconds, indicates what should happen if a child, upon being %% restarted, exceeds the MaxT and MaxR parameters. Thus, if a %% child exits, it is restarted as normal. If it exits sufficiently %% quickly and often to exceed the boundaries set by the MaxT and %% MaxR parameters, and a Delay is specified, then rather than %% stopping the supervisor, the supervisor instead continues and %% tries to start up the child again, Delay seconds later. %% %% Note that you can never restart more frequently than the MaxT %% and MaxR parameters allow: i.e. you must wait until *both* the %% Delay has passed *and* the MaxT and MaxR parameters allow the %% child to be restarted. %% %% Also note that the Delay is a *minimum*. There is no guarantee %% that the child will be restarted within that time, especially if %% other processes are dying and being restarted at the same time - %% essentially we have to wait for the delay to have passed and for %% the MaxT and MaxR parameters to permit the child to be %% restarted. This may require waiting for longer than Delay. %% %% Sometimes, you may wish for a transient or intrinsic child to %% exit abnormally so that it gets restarted, but still log %% nothing. gen_server will log any exit reason other than %% 'normal', 'shutdown' or {'shutdown', _}. Thus the exit reason of %% {'shutdown', 'restart'} is interpreted to mean you wish the %% child to be restarted according to the delay parameters, but %% gen_server will not log the error. Thus from gen_server's %% perspective it's a normal exit, whilst from supervisor's %% perspective, it's an abnormal exit. %% %% 4) Added an 'intrinsic' restart type. Like the transient type, this %% type means the child should only be restarted if the child exits %% abnormally. Unlike the transient type, if the child exits %% normally, the supervisor itself also exits normally. If the %% child is a supervisor and it exits normally (i.e. with reason of %% 'shutdown') then the child's parent also exits normally. %% %% 5) normal, and {shutdown, _} exit reasons are all treated the same %% (i.e. are regarded as normal exits) %% %% All modifications are (C) 2010-2013 VMware, Inc. %% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2009. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in %% compliance with the License. You should have received a copy of the %% Erlang Public License along with this software. If not, it can be %% retrieved online at http://www.erlang.org/. %% %% Software distributed under the License is distributed on an "AS IS" %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See %% the License for the specific language governing rights and limitations %% under the License. %% %% %CopyrightEnd% %% -module(supervisor2). -behaviour(gen_server). %% External exports -export([start_link/2,start_link/3, start_child/2, restart_child/2, delete_child/2, terminate_child/2, which_children/1, find_child/2, check_childspecs/1]). %% Internal exports -export([init/1, handle_call/3, handle_info/2, terminate/2, code_change/3]). -export([handle_cast/2]). -define(DICT, dict). -record(state, {name, strategy, children = [], dynamics = ?DICT:new(), intensity, period, restarts = [], module, args}). -record(child, {pid = undefined, % pid is undefined when child is not running name, mfa, restart_type, shutdown, child_type, modules = []}). -define(is_simple(State), State#state.strategy =:= simple_one_for_one orelse State#state.strategy =:= simple_one_for_one_terminate). -define(is_terminate_simple(State), State#state.strategy =:= simple_one_for_one_terminate). -ifdef(use_specs). %%-------------------------------------------------------------------------- %% Types %%-------------------------------------------------------------------------- -export_type([child_spec/0, startchild_ret/0, strategy/0, sup_name/0]). -type child() :: 'undefined' | pid(). -type child_id() :: term(). -type mfargs() :: {M :: module(), F :: atom(), A :: [term()] | undefined}. -type modules() :: [module()] | 'dynamic'. -type delay() :: non_neg_integer(). -type restart() :: 'permanent' | 'transient' | 'temporary' | 'intrinsic' | {'permanent', delay()} | {'transient', delay()} | {'intrinsic', delay()}. -type shutdown() :: 'brutal_kill' | timeout(). -type worker() :: 'worker' | 'supervisor'. -type sup_name() :: {'local', Name :: atom()} | {'global', Name :: atom()}. -type sup_ref() :: (Name :: atom()) | {Name :: atom(), Node :: node()} | {'global', Name :: atom()} | pid(). -type child_spec() :: {Id :: child_id(), StartFunc :: mfargs(), Restart :: restart(), Shutdown :: shutdown(), Type :: worker(), Modules :: modules()}. -type strategy() :: 'one_for_all' | 'one_for_one' | 'rest_for_one' | 'simple_one_for_one' | 'simple_one_for_one_terminate'. -type child_rec() :: #child{pid :: child() | {restarting,pid()} | [pid()], name :: child_id(), mfa :: mfargs(), restart_type :: restart(), shutdown :: shutdown(), child_type :: worker(), modules :: modules()}. -type state() :: #state{strategy :: strategy(), children :: [child_rec()], dynamics :: ?DICT(), intensity :: non_neg_integer(), period :: pos_integer()}. %%-------------------------------------------------------------------------- %% Callback behaviour %%-------------------------------------------------------------------------- -callback init(Args :: term()) -> {ok, {{RestartStrategy :: strategy(), MaxR :: non_neg_integer(), MaxT :: non_neg_integer()}, [ChildSpec :: child_spec()]}} | ignore. %%-------------------------------------------------------------------------- %% Specs %%-------------------------------------------------------------------------- -type startchild_err() :: 'already_present' | {'already_started', Child :: child()} | term(). -type startchild_ret() :: {'ok', Child :: child()} | {'ok', Child :: child(), Info :: term()} | {'error', startchild_err()}. -spec start_child(SupRef, ChildSpec) -> startchild_ret() when SupRef :: sup_ref(), ChildSpec :: child_spec() | (List :: [term()]). -spec restart_child(SupRef, Id) -> Result when SupRef :: sup_ref(), Id :: child_id(), Result :: {'ok', Child :: child()} | {'ok', Child :: child(), Info :: term()} | {'error', Error}, Error :: 'running' | 'not_found' | 'simple_one_for_one' | term(). -spec delete_child(SupRef, Id) -> Result when SupRef :: sup_ref(), Id :: child_id(), Result :: 'ok' | {'error', Error}, Error :: 'running' | 'not_found' | 'simple_one_for_one'. -spec terminate_child(SupRef, Id) -> Result when SupRef :: sup_ref(), Id :: pid() | child_id(), Result :: 'ok' | {'error', Error}, Error :: 'not_found' | 'simple_one_for_one'. -spec which_children(SupRef) -> [{Id,Child,Type,Modules}] when SupRef :: sup_ref(), Id :: child_id() | 'undefined', Child :: child(), Type :: worker(), Modules :: modules(). -spec check_childspecs(ChildSpecs) -> Result when ChildSpecs :: [child_spec()], Result :: 'ok' | {'error', Error :: term()}. -type init_sup_name() :: sup_name() | 'self'. -type stop_rsn() :: 'shutdown' | {'bad_return', {module(),'init', term()}} | {'bad_start_spec', term()} | {'start_spec', term()} | {'supervisor_data', term()}. -spec init({init_sup_name(), module(), [term()]}) -> {'ok', state()} | 'ignore' | {'stop', stop_rsn()}. -type call() :: 'which_children'. -spec handle_call(call(), term(), state()) -> {'reply', term(), state()}. -spec handle_cast('null', state()) -> {'noreply', state()}. -spec handle_info(term(), state()) -> {'noreply', state()} | {'stop', 'shutdown', state()}. -spec terminate(term(), state()) -> 'ok'. -spec code_change(term(), state(), term()) -> {'ok', state()} | {'error', term()}. -else. -export([behaviour_info/1]). behaviour_info(callbacks) -> [{init,1}]; behaviour_info(_Other) -> undefined. -endif. %%% --------------------------------------------------- %%% This is a general process supervisor built upon gen_server.erl. %%% Servers/processes should/could also be built using gen_server.erl. %%% SupName = {local, atom()} | {global, atom()}. %%% --------------------------------------------------- start_link(Mod, Args) -> gen_server:start_link(?MODULE, {self, Mod, Args}, []). start_link(SupName, Mod, Args) -> gen_server:start_link(SupName, ?MODULE, {SupName, Mod, Args}, []). %%% --------------------------------------------------- %%% Interface functions. %%% --------------------------------------------------- start_child(Supervisor, ChildSpec) -> call(Supervisor, {start_child, ChildSpec}). restart_child(Supervisor, Name) -> call(Supervisor, {restart_child, Name}). delete_child(Supervisor, Name) -> call(Supervisor, {delete_child, Name}). %%----------------------------------------------------------------- %% Func: terminate_child/2 %% Returns: ok | {error, Reason} %% Note that the child is *always* terminated in some %% way (maybe killed). %%----------------------------------------------------------------- terminate_child(Supervisor, Name) -> call(Supervisor, {terminate_child, Name}). which_children(Supervisor) -> call(Supervisor, which_children). find_child(Supervisor, Name) -> [Pid || {Name1, Pid, _Type, _Modules} <- which_children(Supervisor), Name1 =:= Name]. call(Supervisor, Req) -> gen_server:call(Supervisor, Req, infinity). check_childspecs(ChildSpecs) when is_list(ChildSpecs) -> case check_startspec(ChildSpecs) of {ok, _} -> ok; Error -> {error, Error} end; check_childspecs(X) -> {error, {badarg, X}}. %%% --------------------------------------------------- %%% %%% Initialize the supervisor. %%% %%% --------------------------------------------------- init({SupName, Mod, Args}) -> process_flag(trap_exit, true), case Mod:init(Args) of {ok, {SupFlags, StartSpec}} -> case init_state(SupName, SupFlags, Mod, Args) of {ok, State} when ?is_simple(State) -> init_dynamic(State, StartSpec); {ok, State} -> init_children(State, StartSpec); Error -> {stop, {supervisor_data, Error}} end; ignore -> ignore; Error -> {stop, {bad_return, {Mod, init, Error}}} end. init_children(State, StartSpec) -> SupName = State#state.name, case check_startspec(StartSpec) of {ok, Children} -> case start_children(Children, SupName) of {ok, NChildren} -> {ok, State#state{children = NChildren}}; {error, NChildren} -> terminate_children(NChildren, SupName), {stop, shutdown} end; Error -> {stop, {start_spec, Error}} end. init_dynamic(State, [StartSpec]) -> case check_startspec([StartSpec]) of {ok, Children} -> {ok, State#state{children = Children}}; Error -> {stop, {start_spec, Error}} end; init_dynamic(_State, StartSpec) -> {stop, {bad_start_spec, StartSpec}}. %%----------------------------------------------------------------- %% Func: start_children/2 %% Args: Children = [#child] in start order %% SupName = {local, atom()} | {global, atom()} | {pid(),Mod} %% Purpose: Start all children. The new list contains #child's %% with pids. %% Returns: {ok, NChildren} | {error, NChildren} %% NChildren = [#child] in termination order (reversed %% start order) %%----------------------------------------------------------------- start_children(Children, SupName) -> start_children(Children, [], SupName). start_children([Child|Chs], NChildren, SupName) -> case do_start_child(SupName, Child) of {ok, Pid} -> start_children(Chs, [Child#child{pid = Pid}|NChildren], SupName); {ok, Pid, _Extra} -> start_children(Chs, [Child#child{pid = Pid}|NChildren], SupName); {error, Reason} -> report_error(start_error, Reason, Child, SupName), {error, lists:reverse(Chs) ++ [Child | NChildren]} end; start_children([], NChildren, _SupName) -> {ok, NChildren}. do_start_child(SupName, Child) -> #child{mfa = {M, F, A}} = Child, case catch apply(M, F, A) of {ok, Pid} when is_pid(Pid) -> NChild = Child#child{pid = Pid}, report_progress(NChild, SupName), {ok, Pid}; {ok, Pid, Extra} when is_pid(Pid) -> NChild = Child#child{pid = Pid}, report_progress(NChild, SupName), {ok, Pid, Extra}; ignore -> {ok, undefined}; {error, What} -> {error, What}; What -> {error, What} end. do_start_child_i(M, F, A) -> case catch apply(M, F, A) of {ok, Pid} when is_pid(Pid) -> {ok, Pid}; {ok, Pid, Extra} when is_pid(Pid) -> {ok, Pid, Extra}; ignore -> {ok, undefined}; {error, Error} -> {error, Error}; What -> {error, What} end. %%% --------------------------------------------------- %%% %%% Callback functions. %%% %%% --------------------------------------------------- handle_call({start_child, EArgs}, _From, State) when ?is_simple(State) -> #child{mfa = {M, F, A}} = hd(State#state.children), Args = A ++ EArgs, case do_start_child_i(M, F, Args) of {ok, undefined} -> {reply, {ok, undefined}, State}; {ok, Pid} -> NState = State#state{dynamics = ?DICT:store(Pid, Args, State#state.dynamics)}, {reply, {ok, Pid}, NState}; {ok, Pid, Extra} -> NState = State#state{dynamics = ?DICT:store(Pid, Args, State#state.dynamics)}, {reply, {ok, Pid, Extra}, NState}; What -> {reply, What, State} end; %%% The requests terminate_child, delete_child and restart_child are %%% invalid for simple_one_for_one and simple_one_for_one_terminate %%% supervisors. handle_call({_Req, _Data}, _From, State) when ?is_simple(State) -> {reply, {error, State#state.strategy}, State}; handle_call({start_child, ChildSpec}, _From, State) -> case check_childspec(ChildSpec) of {ok, Child} -> {Resp, NState} = handle_start_child(Child, State), {reply, Resp, NState}; What -> {reply, {error, What}, State} end; handle_call({restart_child, Name}, _From, State) -> case get_child(Name, State) of {value, Child} when Child#child.pid =:= undefined -> case do_start_child(State#state.name, Child) of {ok, Pid} -> NState = replace_child(Child#child{pid = Pid}, State), {reply, {ok, Pid}, NState}; {ok, Pid, Extra} -> NState = replace_child(Child#child{pid = Pid}, State), {reply, {ok, Pid, Extra}, NState}; Error -> {reply, Error, State} end; {value, _} -> {reply, {error, running}, State}; _ -> {reply, {error, not_found}, State} end; handle_call({delete_child, Name}, _From, State) -> case get_child(Name, State) of {value, Child} when Child#child.pid =:= undefined -> NState = remove_child(Child, State), {reply, ok, NState}; {value, _} -> {reply, {error, running}, State}; _ -> {reply, {error, not_found}, State} end; handle_call({terminate_child, Name}, _From, State) -> case get_child(Name, State) of {value, Child} -> NChild = do_terminate(Child, State#state.name), {reply, ok, replace_child(NChild, State)}; _ -> {reply, {error, not_found}, State} end; handle_call(which_children, _From, State) when ?is_simple(State) -> [#child{child_type = CT, modules = Mods}] = State#state.children, Reply = lists:map(fun ({Pid, _}) -> {undefined, Pid, CT, Mods} end, ?DICT:to_list(State#state.dynamics)), {reply, Reply, State}; handle_call(which_children, _From, State) -> Resp = lists:map(fun (#child{pid = Pid, name = Name, child_type = ChildType, modules = Mods}) -> {Name, Pid, ChildType, Mods} end, State#state.children), {reply, Resp, State}. %%% Hopefully cause a function-clause as there is no API function %%% that utilizes cast. handle_cast(null, State) -> error_logger:error_msg("ERROR: Supervisor received cast-message 'null'~n", []), {noreply, State}. handle_info({delayed_restart, {RestartType, Reason, Child}}, State) when ?is_simple(State) -> {ok, NState} = do_restart(RestartType, Reason, Child, State), {noreply, NState}; handle_info({delayed_restart, {RestartType, Reason, Child}}, State) -> case get_child(Child#child.name, State) of {value, Child1} -> {ok, NState} = do_restart(RestartType, Reason, Child1, State), {noreply, NState}; _ -> {noreply, State} end; %% %% Take care of terminated children. %% handle_info({'EXIT', Pid, Reason}, State) -> case restart_child(Pid, Reason, State) of {ok, State1} -> {noreply, State1}; {shutdown, State1} -> {stop, shutdown, State1} end; handle_info(Msg, State) -> error_logger:error_msg("Supervisor received unexpected message: ~p~n", [Msg]), {noreply, State}. %% %% Terminate this server. %% terminate(_Reason, State) when ?is_terminate_simple(State) -> terminate_simple_children( hd(State#state.children), State#state.dynamics, State#state.name), ok; terminate(_Reason, State) -> terminate_children(State#state.children, State#state.name), ok. %% %% Change code for the supervisor. %% Call the new call-back module and fetch the new start specification. %% Combine the new spec. with the old. If the new start spec. is %% not valid the code change will not succeed. %% Use the old Args as argument to Module:init/1. %% NOTE: This requires that the init function of the call-back module %% does not have any side effects. %% code_change(_, State, _) -> case (State#state.module):init(State#state.args) of {ok, {SupFlags, StartSpec}} -> case catch check_flags(SupFlags) of ok -> {Strategy, MaxIntensity, Period} = SupFlags, update_childspec(State#state{strategy = Strategy, intensity = MaxIntensity, period = Period}, StartSpec); Error -> {error, Error} end; ignore -> {ok, State}; Error -> Error end. check_flags({Strategy, MaxIntensity, Period}) -> validStrategy(Strategy), validIntensity(MaxIntensity), validPeriod(Period), ok; check_flags(What) -> {bad_flags, What}. update_childspec(State, StartSpec) when ?is_simple(State) -> case check_startspec(StartSpec) of {ok, [Child]} -> {ok, State#state{children = [Child]}}; Error -> {error, Error} end; update_childspec(State, StartSpec) -> case check_startspec(StartSpec) of {ok, Children} -> OldC = State#state.children, % In reverse start order ! NewC = update_childspec1(OldC, Children, []), {ok, State#state{children = NewC}}; Error -> {error, Error} end. update_childspec1([Child|OldC], Children, KeepOld) -> case update_chsp(Child, Children) of {ok,NewChildren} -> update_childspec1(OldC, NewChildren, KeepOld); false -> update_childspec1(OldC, Children, [Child|KeepOld]) end; update_childspec1([], Children, KeepOld) -> % Return them in (keeped) reverse start order. lists:reverse(Children ++ KeepOld). update_chsp(OldCh, Children) -> case lists:map(fun (Ch) when OldCh#child.name =:= Ch#child.name -> Ch#child{pid = OldCh#child.pid}; (Ch) -> Ch end, Children) of Children -> false; % OldCh not found in new spec. NewC -> {ok, NewC} end. %%% --------------------------------------------------- %%% Start a new child. %%% --------------------------------------------------- handle_start_child(Child, State) -> case get_child(Child#child.name, State) of false -> case do_start_child(State#state.name, Child) of {ok, Pid} -> Children = State#state.children, {{ok, Pid}, State#state{children = [Child#child{pid = Pid}|Children]}}; {ok, Pid, Extra} -> Children = State#state.children, {{ok, Pid, Extra}, State#state{children = [Child#child{pid = Pid}|Children]}}; {error, What} -> {{error, {What, Child}}, State} end; {value, OldChild} when OldChild#child.pid =/= undefined -> {{error, {already_started, OldChild#child.pid}}, State}; {value, _OldChild} -> {{error, already_present}, State} end. %%% --------------------------------------------------- %%% Restart. A process has terminated. %%% Returns: {ok, #state} | {shutdown, #state} %%% --------------------------------------------------- restart_child(Pid, Reason, State) when ?is_simple(State) -> case ?DICT:find(Pid, State#state.dynamics) of {ok, Args} -> [Child] = State#state.children, RestartType = Child#child.restart_type, {M, F, _} = Child#child.mfa, NChild = Child#child{pid = Pid, mfa = {M, F, Args}}, do_restart(RestartType, Reason, NChild, State); error -> {ok, State} end; restart_child(Pid, Reason, State) -> Children = State#state.children, case lists:keysearch(Pid, #child.pid, Children) of {value, Child} -> RestartType = Child#child.restart_type, do_restart(RestartType, Reason, Child, State); _ -> {ok, State} end. do_restart({permanent = RestartType, Delay}, Reason, Child, State) -> do_restart_delay({RestartType, Delay}, Reason, Child, State); do_restart(permanent, Reason, Child, State) -> report_error(child_terminated, Reason, Child, State#state.name), restart(Child, State); do_restart(Type, normal, Child, State) -> del_child_and_maybe_shutdown(Type, Child, State); do_restart({RestartType, Delay}, {shutdown, restart} = Reason, Child, State) when RestartType =:= transient orelse RestartType =:= intrinsic -> do_restart_delay({RestartType, Delay}, Reason, Child, State); do_restart(Type, {shutdown, _}, Child, State) -> del_child_and_maybe_shutdown(Type, Child, State); do_restart(Type, shutdown, Child = #child{child_type = supervisor}, State) -> del_child_and_maybe_shutdown(Type, Child, State); do_restart({RestartType, Delay}, Reason, Child, State) when RestartType =:= transient orelse RestartType =:= intrinsic -> do_restart_delay({RestartType, Delay}, Reason, Child, State); do_restart(Type, Reason, Child, State) when Type =:= transient orelse Type =:= intrinsic -> report_error(child_terminated, Reason, Child, State#state.name), restart(Child, State); do_restart(temporary, Reason, Child, State) -> report_error(child_terminated, Reason, Child, State#state.name), NState = state_del_child(Child, State), {ok, NState}. do_restart_delay({RestartType, Delay}, Reason, Child, State) -> case restart1(Child, State) of {ok, NState} -> {ok, NState}; {terminate, NState} -> _TRef = erlang:send_after(trunc(Delay*1000), self(), {delayed_restart, {{RestartType, Delay}, Reason, Child}}), {ok, state_del_child(Child, NState)} end. del_child_and_maybe_shutdown(intrinsic, Child, State) -> {shutdown, state_del_child(Child, State)}; del_child_and_maybe_shutdown({intrinsic, _Delay}, Child, State) -> {shutdown, state_del_child(Child, State)}; del_child_and_maybe_shutdown(_, Child, State) -> {ok, state_del_child(Child, State)}. restart(Child, State) -> case add_restart(State) of {ok, NState} -> restart(NState#state.strategy, Child, NState, fun restart/2); {terminate, NState} -> report_error(shutdown, reached_max_restart_intensity, Child, State#state.name), {shutdown, state_del_child(Child, NState)} end. restart1(Child, State) -> case add_restart(State) of {ok, NState} -> restart(NState#state.strategy, Child, NState, fun restart1/2); {terminate, _NState} -> %% we've reached the max restart intensity, but the %% add_restart will have added to the restarts %% field. Given we don't want to die here, we need to go %% back to the old restarts field otherwise we'll never %% attempt to restart later. {terminate, State} end. restart(Strategy, Child, State, Restart) when Strategy =:= simple_one_for_one orelse Strategy =:= simple_one_for_one_terminate -> #child{mfa = {M, F, A}} = Child, Dynamics = ?DICT:erase(Child#child.pid, State#state.dynamics), case do_start_child_i(M, F, A) of {ok, undefined} -> {ok, State}; {ok, Pid} -> NState = State#state{dynamics = ?DICT:store(Pid, A, Dynamics)}, {ok, NState}; {ok, Pid, _Extra} -> NState = State#state{dynamics = ?DICT:store(Pid, A, Dynamics)}, {ok, NState}; {error, Error} -> report_error(start_error, Error, Child, State#state.name), Restart(Child, State) end; restart(one_for_one, Child, State, Restart) -> case do_start_child(State#state.name, Child) of {ok, Pid} -> NState = replace_child(Child#child{pid = Pid}, State), {ok, NState}; {ok, Pid, _Extra} -> NState = replace_child(Child#child{pid = Pid}, State), {ok, NState}; {error, Reason} -> report_error(start_error, Reason, Child, State#state.name), Restart(Child, State) end; restart(rest_for_one, Child, State, Restart) -> {ChAfter, ChBefore} = split_child(Child#child.pid, State#state.children), ChAfter2 = terminate_children(ChAfter, State#state.name), case start_children(ChAfter2, State#state.name) of {ok, ChAfter3} -> {ok, State#state{children = ChAfter3 ++ ChBefore}}; {error, ChAfter3} -> Restart(Child, State#state{children = ChAfter3 ++ ChBefore}) end; restart(one_for_all, Child, State, Restart) -> Children1 = del_child(Child#child.pid, State#state.children), Children2 = terminate_children(Children1, State#state.name), case start_children(Children2, State#state.name) of {ok, NChs} -> {ok, State#state{children = NChs}}; {error, NChs} -> Restart(Child, State#state{children = NChs}) end. %%----------------------------------------------------------------- %% Func: terminate_children/2 %% Args: Children = [#child] in termination order %% SupName = {local, atom()} | {global, atom()} | {pid(),Mod} %% Returns: NChildren = [#child] in %% startup order (reversed termination order) %%----------------------------------------------------------------- terminate_children(Children, SupName) -> terminate_children(Children, SupName, []). terminate_children([Child | Children], SupName, Res) -> NChild = do_terminate(Child, SupName), terminate_children(Children, SupName, [NChild | Res]); terminate_children([], _SupName, Res) -> Res. terminate_simple_children(Child, Dynamics, SupName) -> Pids = dict:fold(fun (Pid, _Args, Pids) -> erlang:monitor(process, Pid), unlink(Pid), exit(Pid, child_exit_reason(Child)), [Pid | Pids] end, [], Dynamics), TimeoutMsg = {timeout, make_ref()}, TRef = timeout_start(Child, TimeoutMsg), {Replies, Timedout} = lists:foldl( fun (_Pid, {Replies, Timedout}) -> {Pid1, Reason1, Timedout1} = receive TimeoutMsg -> Remaining = Pids -- [P || {P, _} <- Replies], [exit(P, kill) || P <- Remaining], receive {'DOWN', _MRef, process, Pid, Reason} -> {Pid, Reason, true} end; {'DOWN', _MRef, process, Pid, Reason} -> {Pid, Reason, Timedout} end, {[{Pid1, child_res(Child, Reason1, Timedout1)} | Replies], Timedout1} end, {[], false}, Pids), timeout_stop(Child, TRef, TimeoutMsg, Timedout), ReportError = shutdown_error_reporter(SupName), Report = fun(_, ok) -> ok; (Pid, {error, R}) -> ReportError(R, Child#child{pid = Pid}) end, [receive {'EXIT', Pid, Reason} -> Report(Pid, child_res(Child, Reason, Timedout)) after 0 -> Report(Pid, Reply) end || {Pid, Reply} <- Replies], ok. child_exit_reason(#child{shutdown = brutal_kill}) -> kill; child_exit_reason(#child{}) -> shutdown. child_res(#child{shutdown=brutal_kill}, killed, false) -> ok; child_res(#child{}, shutdown, false) -> ok; child_res(#child{restart_type=permanent}, normal, false) -> {error, normal}; child_res(#child{restart_type={permanent,_}},normal, false) -> {error, normal}; child_res(#child{}, normal, false) -> ok; child_res(#child{}, R, _) -> {error, R}. timeout_start(#child{shutdown = Time}, Msg) when is_integer(Time) -> erlang:send_after(Time, self(), Msg); timeout_start(#child{}, _Msg) -> ok. timeout_stop(#child{shutdown = Time}, TRef, Msg, false) when is_integer(Time) -> erlang:cancel_timer(TRef), receive Msg -> ok after 0 -> ok end; timeout_stop(#child{}, _TRef, _Msg, _Timedout) -> ok. do_terminate(Child, SupName) when Child#child.pid =/= undefined -> ReportError = shutdown_error_reporter(SupName), case shutdown(Child#child.pid, Child#child.shutdown) of ok -> ok; {error, normal} -> case Child#child.restart_type of permanent -> ReportError(normal, Child); {permanent, _Delay} -> ReportError(normal, Child); _ -> ok end; {error, OtherReason} -> ReportError(OtherReason, Child) end, Child#child{pid = undefined}; do_terminate(Child, _SupName) -> Child. %%----------------------------------------------------------------- %% Shutdowns a child. We must check the EXIT value %% of the child, because it might have died with another reason than %% the wanted. In that case we want to report the error. We put a %% monitor on the child an check for the 'DOWN' message instead of %% checking for the 'EXIT' message, because if we check the 'EXIT' %% message a "naughty" child, who does unlink(Sup), could hang the %% supervisor. %% Returns: ok | {error, OtherReason} (this should be reported) %%----------------------------------------------------------------- shutdown(Pid, brutal_kill) -> case monitor_child(Pid) of ok -> exit(Pid, kill), receive {'DOWN', _MRef, process, Pid, killed} -> ok; {'DOWN', _MRef, process, Pid, OtherReason} -> {error, OtherReason} end; {error, Reason} -> {error, Reason} end; shutdown(Pid, Time) -> case monitor_child(Pid) of ok -> exit(Pid, shutdown), %% Try to shutdown gracefully receive {'DOWN', _MRef, process, Pid, shutdown} -> ok; {'DOWN', _MRef, process, Pid, OtherReason} -> {error, OtherReason} after Time -> exit(Pid, kill), %% Force termination. receive {'DOWN', _MRef, process, Pid, OtherReason} -> {error, OtherReason} end end; {error, Reason} -> {error, Reason} end. %% Help function to shutdown/2 switches from link to monitor approach monitor_child(Pid) -> %% Do the monitor operation first so that if the child dies %% before the monitoring is done causing a 'DOWN'-message with %% reason noproc, we will get the real reason in the 'EXIT'-message %% unless a naughty child has already done unlink... erlang:monitor(process, Pid), unlink(Pid), receive %% If the child dies before the unlik we must empty %% the mail-box of the 'EXIT'-message and the 'DOWN'-message. {'EXIT', Pid, Reason} -> receive {'DOWN', _, process, Pid, _} -> {error, Reason} end after 0 -> %% If a naughty child did unlink and the child dies before %% monitor the result will be that shutdown/2 receives a %% 'DOWN'-message with reason noproc. %% If the child should die after the unlink there %% will be a 'DOWN'-message with a correct reason %% that will be handled in shutdown/2. ok end. %%----------------------------------------------------------------- %% Child/State manipulating functions. %%----------------------------------------------------------------- state_del_child(#child{pid = Pid}, State) when ?is_simple(State) -> NDynamics = ?DICT:erase(Pid, State#state.dynamics), State#state{dynamics = NDynamics}; state_del_child(Child, State) -> NChildren = del_child(Child#child.name, State#state.children), State#state{children = NChildren}. del_child(Name, [Ch|Chs]) when Ch#child.name =:= Name -> [Ch#child{pid = undefined} | Chs]; del_child(Pid, [Ch|Chs]) when Ch#child.pid =:= Pid -> [Ch#child{pid = undefined} | Chs]; del_child(Name, [Ch|Chs]) -> [Ch|del_child(Name, Chs)]; del_child(_, []) -> []. %% Chs = [S4, S3, Ch, S1, S0] %% Ret: {[S4, S3, Ch], [S1, S0]} split_child(Name, Chs) -> split_child(Name, Chs, []). split_child(Name, [Ch|Chs], After) when Ch#child.name =:= Name -> {lists:reverse([Ch#child{pid = undefined} | After]), Chs}; split_child(Pid, [Ch|Chs], After) when Ch#child.pid =:= Pid -> {lists:reverse([Ch#child{pid = undefined} | After]), Chs}; split_child(Name, [Ch|Chs], After) -> split_child(Name, Chs, [Ch | After]); split_child(_, [], After) -> {lists:reverse(After), []}. get_child(Name, State) -> lists:keysearch(Name, #child.name, State#state.children). replace_child(Child, State) -> Chs = do_replace_child(Child, State#state.children), State#state{children = Chs}. do_replace_child(Child, [Ch|Chs]) when Ch#child.name =:= Child#child.name -> [Child | Chs]; do_replace_child(Child, [Ch|Chs]) -> [Ch|do_replace_child(Child, Chs)]. remove_child(Child, State) -> Chs = lists:keydelete(Child#child.name, #child.name, State#state.children), State#state{children = Chs}. %%----------------------------------------------------------------- %% Func: init_state/4 %% Args: SupName = {local, atom()} | {global, atom()} | self %% Type = {Strategy, MaxIntensity, Period} %% Strategy = one_for_one | one_for_all | simple_one_for_one | %% rest_for_one %% MaxIntensity = integer() %% Period = integer() %% Mod :== atom() %% Arsg :== term() %% Purpose: Check that Type is of correct type (!) %% Returns: {ok, #state} | Error %%----------------------------------------------------------------- init_state(SupName, Type, Mod, Args) -> case catch init_state1(SupName, Type, Mod, Args) of {ok, State} -> {ok, State}; Error -> Error end. init_state1(SupName, {Strategy, MaxIntensity, Period}, Mod, Args) -> validStrategy(Strategy), validIntensity(MaxIntensity), validPeriod(Period), {ok, #state{name = supname(SupName,Mod), strategy = Strategy, intensity = MaxIntensity, period = Period, module = Mod, args = Args}}; init_state1(_SupName, Type, _, _) -> {invalid_type, Type}. validStrategy(simple_one_for_one_terminate) -> true; validStrategy(simple_one_for_one) -> true; validStrategy(one_for_one) -> true; validStrategy(one_for_all) -> true; validStrategy(rest_for_one) -> true; validStrategy(What) -> throw({invalid_strategy, What}). validIntensity(Max) when is_integer(Max), Max >= 0 -> true; validIntensity(What) -> throw({invalid_intensity, What}). validPeriod(Period) when is_integer(Period), Period > 0 -> true; validPeriod(What) -> throw({invalid_period, What}). supname(self,Mod) -> {self(),Mod}; supname(N,_) -> N. %%% ------------------------------------------------------ %%% Check that the children start specification is valid. %%% Shall be a six (6) tuple %%% {Name, Func, RestartType, Shutdown, ChildType, Modules} %%% where Name is an atom %%% Func is {Mod, Fun, Args} == {atom, atom, list} %%% RestartType is permanent | temporary | transient | %%% intrinsic | {permanent, Delay} | %%% {transient, Delay} | {intrinsic, Delay} %% where Delay >= 0 %%% Shutdown = integer() | infinity | brutal_kill %%% ChildType = supervisor | worker %%% Modules = [atom()] | dynamic %%% Returns: {ok, [#child]} | Error %%% ------------------------------------------------------ check_startspec(Children) -> check_startspec(Children, []). check_startspec([ChildSpec|T], Res) -> case check_childspec(ChildSpec) of {ok, Child} -> case lists:keymember(Child#child.name, #child.name, Res) of true -> {duplicate_child_name, Child#child.name}; false -> check_startspec(T, [Child | Res]) end; Error -> Error end; check_startspec([], Res) -> {ok, lists:reverse(Res)}. check_childspec({Name, Func, RestartType, Shutdown, ChildType, Mods}) -> catch check_childspec(Name, Func, RestartType, Shutdown, ChildType, Mods); check_childspec(X) -> {invalid_child_spec, X}. check_childspec(Name, Func, RestartType, Shutdown, ChildType, Mods) -> validName(Name), validFunc(Func), validRestartType(RestartType), validChildType(ChildType), validShutdown(Shutdown, ChildType), validMods(Mods), {ok, #child{name = Name, mfa = Func, restart_type = RestartType, shutdown = Shutdown, child_type = ChildType, modules = Mods}}. validChildType(supervisor) -> true; validChildType(worker) -> true; validChildType(What) -> throw({invalid_child_type, What}). validName(_Name) -> true. validFunc({M, F, A}) when is_atom(M), is_atom(F), is_list(A) -> true; validFunc(Func) -> throw({invalid_mfa, Func}). validRestartType(permanent) -> true; validRestartType(temporary) -> true; validRestartType(transient) -> true; validRestartType(intrinsic) -> true; validRestartType({permanent, Delay}) -> validDelay(Delay); validRestartType({intrinsic, Delay}) -> validDelay(Delay); validRestartType({transient, Delay}) -> validDelay(Delay); validRestartType(RestartType) -> throw({invalid_restart_type, RestartType}). validDelay(Delay) when is_number(Delay), Delay >= 0 -> true; validDelay(What) -> throw({invalid_delay, What}). validShutdown(Shutdown, _) when is_integer(Shutdown), Shutdown > 0 -> true; validShutdown(infinity, supervisor) -> true; validShutdown(brutal_kill, _) -> true; validShutdown(Shutdown, _) -> throw({invalid_shutdown, Shutdown}). validMods(dynamic) -> true; validMods(Mods) when is_list(Mods) -> lists:foreach(fun (Mod) -> if is_atom(Mod) -> ok; true -> throw({invalid_module, Mod}) end end, Mods); validMods(Mods) -> throw({invalid_modules, Mods}). %%% ------------------------------------------------------ %%% Add a new restart and calculate if the max restart %%% intensity has been reached (in that case the supervisor %%% shall terminate). %%% All restarts accured inside the period amount of seconds %%% are kept in the #state.restarts list. %%% Returns: {ok, State'} | {terminate, State'} %%% ------------------------------------------------------ add_restart(State) -> I = State#state.intensity, P = State#state.period, R = State#state.restarts, Now = erlang:now(), R1 = add_restart([Now|R], Now, P), State1 = State#state{restarts = R1}, case length(R1) of CurI when CurI =< I -> {ok, State1}; _ -> {terminate, State1} end. add_restart([R|Restarts], Now, Period) -> case inPeriod(R, Now, Period) of true -> [R|add_restart(Restarts, Now, Period)]; _ -> [] end; add_restart([], _, _) -> []. inPeriod(Time, Now, Period) -> case difference(Time, Now) of T when T > Period -> false; _ -> true end. %% %% Time = {MegaSecs, Secs, MicroSecs} (NOTE: MicroSecs is ignored) %% Calculate the time elapsed in seconds between two timestamps. %% If MegaSecs is equal just subtract Secs. %% Else calculate the Mega difference and add the Secs difference, %% note that Secs difference can be negative, e.g. %% {827, 999999, 676} diff {828, 1, 653753} == > 2 secs. %% difference({TimeM, TimeS, _}, {CurM, CurS, _}) when CurM > TimeM -> ((CurM - TimeM) * 1000000) + (CurS - TimeS); difference({_, TimeS, _}, {_, CurS, _}) -> CurS - TimeS. %%% ------------------------------------------------------ %%% Error and progress reporting. %%% ------------------------------------------------------ report_error(Error, Reason, Child, SupName) -> ErrorMsg = [{supervisor, SupName}, {errorContext, Error}, {reason, Reason}, {offender, extract_child(Child)}], error_logger:error_report(supervisor_report, ErrorMsg). shutdown_error_reporter(SupName) -> fun(Reason, Child) -> report_error(shutdown_error, Reason, Child, SupName) end. extract_child(Child) -> [{pid, Child#child.pid}, {name, Child#child.name}, {mfa, Child#child.mfa}, {restart_type, Child#child.restart_type}, {shutdown, Child#child.shutdown}, {child_type, Child#child.child_type}]. report_progress(Child, SupName) -> Progress = [{supervisor, SupName}, {started, extract_child(Child)}], error_logger:info_report(progress, Progress).