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Diffstat (limited to 'lib/stdlib/src/supervisor.erl')
| -rw-r--r-- | lib/stdlib/src/supervisor.erl | 889 |
1 files changed, 889 insertions, 0 deletions
diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl new file mode 100644 index 0000000000..fb1303d1eb --- /dev/null +++ b/lib/stdlib/src/supervisor.erl @@ -0,0 +1,889 @@ +%% +%% %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(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, + 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]). + +-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). + +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()}. +%%% --------------------------------------------------- +start_link(Mod, Args) -> + gen_server:start_link(supervisor, {self, Mod, Args}, []). + +start_link(SupName, Mod, Args) -> + gen_server:start_link(SupName, supervisor, {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). + +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, 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 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({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}. + +%% +%% 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) -> + 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, 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(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{mfa = {M, F, A}} = Child, + Dynamics = ?DICT:erase(Child#child.pid, 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] 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. + +do_terminate(Child, SupName) when Child#child.pid =/= undefined -> + case shutdown(Child#child.pid, + Child#child.shutdown) of + ok -> + Child#child{pid = undefined}; + {error, OtherReason} -> + report_error(shutdown_error, OtherReason, Child, SupName), + Child#child{pid = undefined} + end; +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) -> 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]} | 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(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}, + {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). |