%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2011. 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(supervisor).
-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, count_children/1,
check_childspecs/1]).
-export([behaviour_info/1]).
%% Internal exports
-export([init/1, handle_call/3, handle_info/2, terminate/2, code_change/3]).
-export([handle_cast/2]).
%%--------------------------------------------------------------------------
-export_type([child_spec/0, startchild_ret/0, strategy/0]).
%%--------------------------------------------------------------------------
-type child() :: pid() | 'undefined'.
-type child_id() :: term().
-type mfargs() :: {M :: module(), F :: atom(), A :: [term()] | undefined}.
-type modules() :: [module()] | 'dynamic'.
-type restart() :: 'permanent' | 'transient' | 'temporary'.
-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'.
%%--------------------------------------------------------------------------
-record(child, {% pid is undefined when child is not running
pid = undefined :: child(),
name,
mfargs :: mfargs(),
restart_type :: restart(),
shutdown :: shutdown(),
child_type :: worker(),
modules = [] :: modules()}).
-type child_rec() :: #child{}.
-define(DICT, dict).
-define(SETS, sets).
-define(SET, set).
-record(state, {name,
strategy :: strategy(),
children = [] :: [child_rec()],
dynamics :: ?DICT() | ?SET(),
intensity :: non_neg_integer(),
period :: pos_integer(),
restarts = [],
module,
args}).
-type state() :: #state{}.
-define(is_simple(State), State#state.strategy =:= simple_one_for_one).
%%--------------------------------------------------------------------------
-spec behaviour_info(atom()) -> 'undefined' | [{atom(), arity()}].
behaviour_info(callbacks) ->
[{init,1}];
behaviour_info(_Other) ->
undefined.
%%% ---------------------------------------------------
%%% 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()}.
%%% ---------------------------------------------------
-type startlink_err() :: {'already_started', pid()} | 'shutdown' | term().
-type startlink_ret() :: {'ok', pid()} | 'ignore' | {'error', startlink_err()}.
-spec start_link(Module, Args) -> startlink_ret() when
Module :: module(),
Args :: term().
start_link(Mod, Args) ->
gen_server:start_link(supervisor, {self, Mod, Args}, []).
-spec start_link(SupName, Module, Args) -> startlink_ret() when
SupName :: sup_name(),
Module :: module(),
Args :: term().
start_link(SupName, Mod, Args) ->
gen_server:start_link(SupName, supervisor, {SupName, Mod, Args}, []).
%%% ---------------------------------------------------
%%% Interface functions.
%%% ---------------------------------------------------
-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()]).
start_child(Supervisor, ChildSpec) ->
call(Supervisor, {start_child, ChildSpec}).
-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().
restart_child(Supervisor, Name) ->
call(Supervisor, {restart_child, Name}).
-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'.
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).
%%-----------------------------------------------------------------
-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'.
terminate_child(Supervisor, Name) ->
call(Supervisor, {terminate_child, Name}).
-spec which_children(SupRef) -> [{Id,Child,Type,Modules}] when
SupRef :: sup_ref(),
Id :: child_id() | undefined,
Child :: child(),
Type :: worker(),
Modules :: modules().
which_children(Supervisor) ->
call(Supervisor, which_children).
-spec count_children(SupRef) -> PropListOfCounts when
SupRef :: sup_ref(),
PropListOfCounts :: [Count],
Count :: {specs, ChildSpecCount :: non_neg_integer()}
| {active, ActiveProcessCount :: non_neg_integer()}
| {supervisors, ChildSupervisorCount :: non_neg_integer()}
|{workers, ChildWorkerCount :: non_neg_integer()}.
count_children(Supervisor) ->
call(Supervisor, count_children).
call(Supervisor, Req) ->
gen_server:call(Supervisor, Req, infinity).
-spec check_childspecs(ChildSpecs) -> Result when
ChildSpecs :: [child_spec()],
Result :: 'ok' | {'error', Error :: term()}.
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.
%%%
%%% ---------------------------------------------------
-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()}.
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_rec()] 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_rec()] 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{mfargs = {M, F, Args}} = Child,
case catch apply(M, F, Args) 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.
%%%
%%% ---------------------------------------------------
-type call() :: 'which_children' | 'count_children' | {_, _}. % XXX: refine
-spec handle_call(call(), term(), state()) -> {'reply', term(), state()}.
handle_call({start_child, EArgs}, _From, State) when ?is_simple(State) ->
Child = hd(State#state.children),
#child{mfargs = {M, F, A}} = Child,
Args = A ++ EArgs,
case do_start_child_i(M, F, Args) of
{ok, Pid} ->
NState = save_dynamic_child(Child#child.restart_type, Pid, Args, State),
{reply, {ok, Pid}, NState};
{ok, Pid, Extra} ->
NState = save_dynamic_child(Child#child.restart_type, Pid, Args, State),
{reply, {ok, Pid, Extra}, NState};
What ->
{reply, What, State}
end;
%% terminate_child for simple_one_for_one can only be done with pid
handle_call({terminate_child, Name}, _From, State) when not is_pid(Name),
?is_simple(State) ->
{reply, {error, simple_one_for_one}, State};
handle_call({terminate_child, Name}, _From, State) ->
case get_child(Name, State, ?is_simple(State)) of
{value, Child} ->
case do_terminate(Child, State#state.name) of
#child{restart_type=RT} when RT=:=temporary; ?is_simple(State) ->
{reply, ok, state_del_child(Child, State)};
NChild ->
{reply, ok, replace_child(NChild, State)}
end;
false ->
{reply, {error, not_found}, State}
end;
%%% The requests delete_child and restart_child are invalid for
%%% simple_one_for_one supervisors.
handle_call({_Req, _Data}, _From, State) when ?is_simple(State) ->
{reply, {error, simple_one_for_one}, 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(which_children, _From, #state{children = [#child{restart_type = temporary,
child_type = CT,
modules = Mods}]} =
State) when ?is_simple(State) ->
Reply = lists:map(fun(Pid) -> {undefined, Pid, CT, Mods} end,
?SETS:to_list(dynamics_db(temporary, State#state.dynamics))),
{reply, Reply, State};
handle_call(which_children, _From, #state{children = [#child{restart_type = RType,
child_type = CT,
modules = Mods}]} =
State) when ?is_simple(State) ->
Reply = lists:map(fun({Pid, _}) -> {undefined, Pid, CT, Mods} end,
?DICT:to_list(dynamics_db(RType, 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};
handle_call(count_children, _From, #state{children = [#child{restart_type = temporary,
child_type = CT}]} = State)
when ?is_simple(State) ->
{Active, Count} =
?SETS:fold(fun(Pid, {Alive, Tot}) ->
if is_pid(Pid) -> {Alive+1, Tot +1};
true -> {Alive, Tot + 1} end
end, {0, 0}, dynamics_db(temporary, State#state.dynamics)),
Reply = case CT of
supervisor -> [{specs, 1}, {active, Active},
{supervisors, Count}, {workers, 0}];
worker -> [{specs, 1}, {active, Active},
{supervisors, 0}, {workers, Count}]
end,
{reply, Reply, State};
handle_call(count_children, _From, #state{children = [#child{restart_type = RType,
child_type = CT}]} = State)
when ?is_simple(State) ->
{Active, Count} =
?DICT:fold(fun(Pid, _Val, {Alive, Tot}) ->
if is_pid(Pid) -> {Alive+1, Tot +1};
true -> {Alive, Tot + 1} end
end, {0, 0}, dynamics_db(RType, State#state.dynamics)),
Reply = case CT of
supervisor -> [{specs, 1}, {active, Active},
{supervisors, Count}, {workers, 0}];
worker -> [{specs, 1}, {active, Active},
{supervisors, 0}, {workers, Count}]
end,
{reply, Reply, State};
handle_call(count_children, _From, State) ->
%% Specs and children are together on the children list...
{Specs, Active, Supers, Workers} =
lists:foldl(fun(Child, Counts) ->
count_child(Child, Counts)
end, {0,0,0,0}, State#state.children),
%% Reformat counts to a property list.
Reply = [{specs, Specs}, {active, Active},
{supervisors, Supers}, {workers, Workers}],
{reply, Reply, State}.
count_child(#child{pid = Pid, child_type = worker},
{Specs, Active, Supers, Workers}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true -> {Specs+1, Active+1, Supers, Workers+1};
false -> {Specs+1, Active, Supers, Workers+1}
end;
count_child(#child{pid = Pid, child_type = supervisor},
{Specs, Active, Supers, Workers}) ->
case is_pid(Pid) andalso is_process_alive(Pid) of
true -> {Specs+1, Active+1, Supers+1, Workers};
false -> {Specs+1, Active, Supers+1, Workers}
end.
%%% Hopefully cause a function-clause as there is no API function
%%% that utilizes cast.
-spec handle_cast('null', state()) -> {'noreply', state()}.
handle_cast(null, State) ->
error_logger:error_msg("ERROR: Supervisor received cast-message 'null'~n",
[]),
{noreply, State}.
%%
%% Take care of terminated children.
%%
-spec handle_info(term(), state()) ->
{'noreply', state()} | {'stop', 'shutdown', state()}.
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.
%%
-spec terminate(term(), state()) -> '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.
%%
-spec code_change(term(), state(), term()) ->
{'ok', state()} | {'error', term()}.
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 (kept) 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} ->
{{ok, Pid},
save_child(Child#child{pid = Pid}, State)};
{ok, Pid, Extra} ->
{{ok, Pid, Extra},
save_child(Child#child{pid = Pid}, State)};
{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{children = [Child]} = State) when ?is_simple(State) ->
RestartType = Child#child.restart_type,
case dynamic_child_args(Pid, dynamics_db(RestartType, State#state.dynamics)) of
{ok, Args} ->
{M, F, _} = Child#child.mfargs,
NChild = Child#child{pid = Pid, mfargs = {M, F, Args}},
do_restart(RestartType, Reason, NChild, State);
error ->
{ok, State}
end;
restart_child(Pid, Reason, State) ->
Children = State#state.children,
case lists:keyfind(Pid, #child.pid, Children) of
#child{restart_type = RestartType} = Child ->
do_restart(RestartType, Reason, Child, State);
false ->
{ok, State}
end.
do_restart(permanent, Reason, Child, State) ->
report_error(child_terminated, Reason, Child, State#state.name),
restart(Child, State);
do_restart(_, normal, Child, State) ->
NState = state_del_child(Child, State),
{ok, NState};
do_restart(_, shutdown, Child, State) ->
NState = state_del_child(Child, State),
{ok, NState};
do_restart(_, {shutdown, _Term}, Child, State) ->
NState = state_del_child(Child, State),
{ok, NState};
do_restart(transient, Reason, Child, State) ->
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}.
restart(Child, State) ->
case add_restart(State) of
{ok, NState} ->
restart(NState#state.strategy, Child, NState);
{terminate, NState} ->
report_error(shutdown, reached_max_restart_intensity,
Child, State#state.name),
{shutdown, remove_child(Child, NState)}
end.
restart(simple_one_for_one, Child, State) ->
#child{mfargs = {M, F, A}} = Child,
Dynamics = ?DICT:erase(Child#child.pid, dynamics_db(Child#child.restart_type,
State#state.dynamics)),
case do_start_child_i(M, F, A) of
{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) ->
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) ->
{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) ->
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_rec()] in termination order
%% SupName = {local, atom()} | {global, atom()} | {pid(),Mod}
%% Returns: NChildren = [child_rec()] 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.
do_terminate(Child, SupName) when Child#child.pid =/= undefined ->
case shutdown(Child#child.pid, Child#child.shutdown) of
ok ->
ok;
{error, normal} when Child#child.restart_type =/= permanent ->
ok;
{error, OtherReason} ->
report_error(shutdown_error, OtherReason, Child, SupName)
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.
%%-----------------------------------------------------------------
%% Note we do not want to save the parameter list for temporary processes as
%% they will not be restarted, and hence we do not need this information.
%% Especially for dynamic children to simple_one_for_one supervisors
%% it could become very costly as it is not uncommon to spawn
%% very many such processes.
save_child(#child{restart_type = temporary,
mfargs = {M, F, _}} = Child, #state{children = Children} = State) ->
State#state{children = [Child#child{mfargs = {M, F, undefined}} |Children]};
save_child(Child, #state{children = Children} = State) ->
State#state{children = [Child |Children]}.
save_dynamic_child(temporary, Pid, _, #state{dynamics = Dynamics} = State) ->
State#state{dynamics = ?SETS:add_element(Pid, dynamics_db(temporary, Dynamics))};
save_dynamic_child(RestartType, Pid, Args, #state{dynamics = Dynamics} = State) ->
State#state{dynamics = ?DICT:store(Pid, Args, dynamics_db(RestartType, Dynamics))}.
dynamics_db(temporary, undefined) ->
?SETS:new();
dynamics_db(_, undefined) ->
?DICT:new();
dynamics_db(_,Dynamics) ->
Dynamics.
dynamic_child_args(Pid, Dynamics) ->
case ?SETS:is_set(Dynamics) of
true ->
{ok, undefined};
false ->
?DICT:find(Pid, Dynamics)
end.
state_del_child(#child{pid = Pid, restart_type = temporary}, State) when ?is_simple(State) ->
NDynamics = ?SETS:del_element(Pid, dynamics_db(temporary, State#state.dynamics)),
State#state{dynamics = NDynamics};
state_del_child(#child{pid = Pid, restart_type = RType}, State) when ?is_simple(State) ->
NDynamics = ?DICT:erase(Pid, dynamics_db(RType, 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.restart_type =:= temporary ->
Chs;
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.restart_type =:= temporary ->
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) ->
get_child(Name, State, false).
get_child(Pid, State, AllowPid) when AllowPid, is_pid(Pid) ->
get_dynamic_child(Pid, State);
get_child(Name, State, _) ->
lists:keysearch(Name, #child.name, State#state.children).
get_dynamic_child(Pid, #state{children=[Child], dynamics=Dynamics}) ->
case is_dynamic_pid(Pid, dynamics_db(Child#child.restart_type, Dynamics)) of
true ->
{value, Child#child{pid=Pid}};
false ->
case erlang:is_process_alive(Pid) of
true -> false;
false -> {value, Child}
end
end.
is_dynamic_pid(Pid, Dynamics) ->
case ?SETS:is_set(Dynamics) of
true ->
?SETS:is_element(Pid, Dynamics);
false ->
?DICT:is_key(Pid, Dynamics)
end.
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()
%% Args :== 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) -> 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
%%% Shutdown = integer() | infinity | brutal_kill
%%% ChildType = supervisor | worker
%%% Modules = [atom()] | dynamic
%%% Returns: {ok, [child_rec()]} | 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, mfargs = 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(RestartType) -> throw({invalid_restart_type, RestartType}).
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).
extract_child(Child) ->
[{pid, Child#child.pid},
{name, Child#child.name},
{mfargs, Child#child.mfargs},
{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).
