% Licensed under the Apache License, Version 2.0 (the "License"); you may not % use this file except in compliance with the License. You may obtain a copy of % the License at % % http://www.apache.org/licenses/LICENSE-2.0 % % Unless required by applicable law or agreed to in writing, software % distributed under the License is distributed on an "AS IS" BASIS, WITHOUT % WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the % License for the specific language governing permissions and limitations under % the License. -module(couch_os_daemons). -behaviour(gen_server). -export([start_link/0, info/0, info/1, config_change/2]). -export([init/1, terminate/2, code_change/3]). -export([handle_call/3, handle_cast/2, handle_info/2]). -include("couch_db.hrl"). -record(daemon, { port, name, cmd, kill, status=running, cfg_patterns=[], errors=[], buf=[] }). -define(PORT_OPTIONS, [stream, {line, 1024}, binary, exit_status, hide]). -define(TIMEOUT, 5000). start_link() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). info() -> info([]). info(Options) -> gen_server:call(?MODULE, {daemon_info, Options}). config_change(Section, Key) -> gen_server:cast(?MODULE, {config_change, Section, Key}). init(_) -> process_flag(trap_exit, true), ok = couch_config:register(fun couch_os_daemons:config_change/2), Table = ets:new(?MODULE, [protected, set, {keypos, #daemon.port}]), reload_daemons(Table), {ok, Table}. terminate(_Reason, Table) -> [stop_port(D) || D <- ets:tab2list(Table)], ok. handle_call({daemon_info, Options}, _From, Table) when is_list(Options) -> case lists:member(table, Options) of true -> {reply, {ok, ets:tab2list(Table)}, Table}; _ -> {reply, {ok, Table}, Table} end; handle_call(Msg, From, Table) -> ?LOG_ERROR("Unknown call message to ~p from ~p: ~p", [?MODULE, From, Msg]), {stop, error, Table}. handle_cast({config_change, Sect, Key}, Table) -> restart_daemons(Table, Sect, Key), case Sect of "os_daemons" -> reload_daemons(Table); _ -> ok end, {noreply, Table}; handle_cast(stop, Table) -> {stop, normal, Table}; handle_cast(Msg, Table) -> ?LOG_ERROR("Unknown cast message to ~p: ~p", [?MODULE, Msg]), {stop, error, Table}. handle_info({'EXIT', Port, Reason}, Table) -> case ets:lookup(Table, Port) of [] -> ?LOG_INFO("Port ~p exited after stopping: ~p~n", [Port, Reason]); [#daemon{status=stopping}] -> true = ets:delete(Table, Port); [#daemon{name=Name, status=restarting}=D] -> ?LOG_INFO("Daemon ~P restarting after config change.", [Name]), true = ets:delete(Table, Port), {ok, Port2} = start_port(D#daemon.cmd), true = ets:insert(Table, D#daemon{ port=Port2, status=running, kill=undefined, buf=[] }); [#daemon{name=Name, status=halted}] -> ?LOG_ERROR("Halted daemon process: ~p", [Name]); [D] -> ?LOG_ERROR("Invalid port state at exit: ~p", [D]) end, {noreply, Table}; handle_info({Port, closed}, Table) -> handle_info({Port, {exit_status, closed}}, Table); handle_info({Port, {exit_status, Status}}, Table) -> case ets:lookup(Table, Port) of [] -> ?LOG_ERROR("Unknown port ~p exiting ~p", [Port, Status]), {stop, {error, unknown_port_died, Status}, Table}; [#daemon{name=Name, status=restarting}=D] -> ?LOG_INFO("Daemon ~P restarting after config change.", [Name]), true = ets:delete(Table, Port), {ok, Port2} = start_port(D#daemon.cmd), true = ets:insert(Table, D#daemon{ port=Port2, status=running, kill=undefined, buf=[] }), {noreply, Table}; [#daemon{status=stopping}=D] -> % The configuration changed and this daemon is no % longer needed. ?LOG_DEBUG("Port ~p shut down.", [D#daemon.name]), true = ets:delete(Table, Port), {noreply, Table}; [D] -> % Port died for unknown reason. Check to see if it's % died too many times or if we should boot it back up. case should_halt([now() | D#daemon.errors]) of {true, _} -> % Halting the process. We won't try and reboot % until the configuration changes. Fmt = "Daemon ~p halted with exit_status ~p", ?LOG_ERROR(Fmt, [D#daemon.name, Status]), D2 = D#daemon{status=halted, errors=nil, buf=nil}, true = ets:insert(Table, D2), {noreply, Table}; {false, Errors} -> % We're guessing it was a random error, this daemon % has behaved so we'll give it another chance. Fmt = "Daemon ~p is being rebooted after exit_status ~p", ?LOG_INFO(Fmt, [D#daemon.name, Status]), true = ets:delete(Table, Port), {ok, Port2} = start_port(D#daemon.cmd), true = ets:insert(Table, D#daemon{ port=Port2, status=running, kill=undefined, errors=Errors, buf=[] }), {noreply, Table} end; _Else -> throw(error) end; handle_info({Port, {data, {noeol, Data}}}, Table) -> [#daemon{buf=Buf}=D] = ets:lookup(Table, Port), true = ets:insert(Table, D#daemon{buf=[Data | Buf]}), {noreply, Table}; handle_info({Port, {data, {eol, Data}}}, Table) -> [#daemon{buf=Buf}=D] = ets:lookup(Table, Port), Line = lists:reverse(Buf, Data), % The first line echoed back is the kill command % for when we go to get rid of the port. Lines after % that are considered part of the stdio API. case D#daemon.kill of undefined -> true = ets:insert(Table, D#daemon{kill=?b2l(Line), buf=[]}); _Else -> D2 = case (catch ?JSON_DECODE(Line)) of {invalid_json, Rejected} -> ?LOG_ERROR("Ignoring OS daemon request: ~p", [Rejected]), D; JSON -> {ok, D3} = handle_port_message(D, JSON), D3 end, true = ets:insert(Table, D2#daemon{buf=[]}) end, {noreply, Table}; handle_info({Port, Error}, Table) -> ?LOG_ERROR("Unexpectd message from port ~p: ~p", [Port, Error]), stop_port(Port), [D] = ets:lookup(Table, Port), true = ets:insert(Table, D#daemon{status=restarting, buf=nil}), {noreply, Table}; handle_info(Msg, Table) -> ?LOG_ERROR("Unexpected info message to ~p: ~p", [?MODULE, Msg]), {stop, error, Table}. code_change(_OldVsn, State, _Extra) -> {ok, State}. % Internal API % % Port management helpers % start_port(Command) -> PrivDir = couch_util:priv_dir(), Spawnkiller = filename:join(PrivDir, "couchspawnkillable"), Port = open_port({spawn, Spawnkiller ++ " " ++ Command}, ?PORT_OPTIONS), {ok, Port}. stop_port(#daemon{port=Port, kill=undefined}=D) -> ?LOG_ERROR("Stopping daemon without a kill command: ~p", [D#daemon.name]), catch port_close(Port); stop_port(#daemon{port=Port}=D) -> ?LOG_DEBUG("Stopping daemon: ~p", [D#daemon.name]), os:cmd(D#daemon.kill), catch port_close(Port). handle_port_message(#daemon{port=Port}=Daemon, [<<"get">>, Section]) -> KVs = couch_config:get(Section), Data = lists:map(fun({K, V}) -> {?l2b(K), ?l2b(V)} end, KVs), Json = iolist_to_binary(?JSON_ENCODE({Data})), port_command(Port, <>), {ok, Daemon}; handle_port_message(#daemon{port=Port}=Daemon, [<<"get">>, Section, Key]) -> Value = case couch_config:get(Section, Key, null) of null -> null; String -> ?l2b(String) end, Json = iolist_to_binary(?JSON_ENCODE(Value)), port_command(Port, <>), {ok, Daemon}; handle_port_message(Daemon, [<<"register">>, Sec]) when is_binary(Sec) -> Patterns = lists:usort(Daemon#daemon.cfg_patterns ++ [{?b2l(Sec)}]), {ok, Daemon#daemon{cfg_patterns=Patterns}}; handle_port_message(Daemon, [<<"register">>, Sec, Key]) when is_binary(Sec) andalso is_binary(Key) -> Pattern = {?b2l(Sec), ?b2l(Key)}, Patterns = lists:usort(Daemon#daemon.cfg_patterns ++ [Pattern]), {ok, Daemon#daemon{cfg_patterns=Patterns}}; handle_port_message(#daemon{name=Name}=Daemon, [<<"log">>, Msg]) -> handle_log_message(Name, Msg, <<"info">>), {ok, Daemon}; handle_port_message(#daemon{name=Name}=Daemon, [<<"log">>, Msg, {Opts}]) -> Level = couch_util:get_value(<<"level">>, Opts, <<"info">>), handle_log_message(Name, Msg, Level), {ok, Daemon}; handle_port_message(#daemon{name=Name}=Daemon, Else) -> ?LOG_ERROR("Daemon ~p made invalid request: ~p", [Name, Else]), {ok, Daemon}. handle_log_message(Name, Msg, _Level) when not is_binary(Msg) -> ?LOG_ERROR("Invalid log message from daemon ~p: ~p", [Name, Msg]); handle_log_message(Name, Msg, <<"debug">>) -> ?LOG_DEBUG("Daemon ~p :: ~s", [Name, ?b2l(Msg)]); handle_log_message(Name, Msg, <<"info">>) -> ?LOG_INFO("Daemon ~p :: ~s", [Name, ?b2l(Msg)]); handle_log_message(Name, Msg, <<"error">>) -> ?LOG_ERROR("Daemon: ~p :: ~s", [Name, ?b2l(Msg)]); handle_log_message(Name, Msg, Level) -> ?LOG_ERROR("Invalid log level from daemon: ~p", [Level]), ?LOG_INFO("Daemon: ~p :: ~s", [Name, ?b2l(Msg)]). % % Daemon management helpers % reload_daemons(Table) -> % List of daemons we want to have running. Configured = lists:sort(couch_config:get("os_daemons")), % Remove records for daemons that were halted. MSpecHalted = #daemon{name='$1', cmd='$2', status=halted, _='_'}, Halted = lists:sort([{N, C} || [N, C] <- ets:match(Table, MSpecHalted)]), ok = stop_os_daemons(Table, find_to_stop(Configured, Halted, [])), % Stop daemons that are running % Start newly configured daemons MSpecRunning = #daemon{name='$1', cmd='$2', status=running, _='_'}, Running = lists:sort([{N, C} || [N, C] <- ets:match(Table, MSpecRunning)]), ok = stop_os_daemons(Table, find_to_stop(Configured, Running, [])), ok = boot_os_daemons(Table, find_to_boot(Configured, Running, [])), ok. restart_daemons(Table, Sect, Key) -> restart_daemons(Table, Sect, Key, ets:first(Table)). restart_daemons(_, _, _, '$end_of_table') -> ok; restart_daemons(Table, Sect, Key, Port) -> [D] = ets:lookup(Table, Port), HasSect = lists:member({Sect}, D#daemon.cfg_patterns), HasKey = lists:member({Sect, Key}, D#daemon.cfg_patterns), case HasSect or HasKey of true -> stop_port(D), D2 = D#daemon{status=restarting, buf=nil}, true = ets:insert(Table, D2); _ -> ok end, restart_daemons(Table, Sect, Key, ets:next(Table, Port)). stop_os_daemons(_Table, []) -> ok; stop_os_daemons(Table, [{Name, Cmd} | Rest]) -> [[Port]] = ets:match(Table, #daemon{port='$1', name=Name, cmd=Cmd, _='_'}), [D] = ets:lookup(Table, Port), case D#daemon.status of halted -> ets:delete(Table, Port); _ -> stop_port(D), D2 = D#daemon{status=stopping, errors=nil, buf=nil}, true = ets:insert(Table, D2) end, stop_os_daemons(Table, Rest). boot_os_daemons(_Table, []) -> ok; boot_os_daemons(Table, [{Name, Cmd} | Rest]) -> {ok, Port} = start_port(Cmd), true = ets:insert(Table, #daemon{port=Port, name=Name, cmd=Cmd}), boot_os_daemons(Table, Rest). % Elements unique to the configured set need to be booted. find_to_boot([], _Rest, Acc) -> % Nothing else configured. Acc; find_to_boot([D | R1], [D | R2], Acc) -> % Elements are equal, daemon already running. find_to_boot(R1, R2, Acc); find_to_boot([D1 | R1], [D2 | _]=A2, Acc) when D1 < D2 -> find_to_boot(R1, A2, [D1 | Acc]); find_to_boot(A1, [_ | R2], Acc) -> find_to_boot(A1, R2, Acc); find_to_boot(Rest, [], Acc) -> % No more candidates for already running. Boot all. Rest ++ Acc. % Elements unique to the running set need to be killed. find_to_stop([], Rest, Acc) -> % The rest haven't been found, so they must all % be ready to die. Rest ++ Acc; find_to_stop([D | R1], [D | R2], Acc) -> % Elements are equal, daemon already running. find_to_stop(R1, R2, Acc); find_to_stop([D1 | R1], [D2 | _]=A2, Acc) when D1 < D2 -> find_to_stop(R1, A2, Acc); find_to_stop(A1, [D2 | R2], Acc) -> find_to_stop(A1, R2, [D2 | Acc]); find_to_stop(_, [], Acc) -> % No more running daemons to worry about. Acc. should_halt(Errors) -> RetryTimeCfg = couch_config:get("os_daemon_settings", "retry_time", "5"), RetryTime = list_to_integer(RetryTimeCfg), Now = now(), RecentErrors = lists:filter(fun(Time) -> timer:now_diff(Now, Time) =< RetryTime * 1000000 end, Errors), RetryCfg = couch_config:get("os_daemon_settings", "max_retries", "3"), Retries = list_to_integer(RetryCfg), {length(RecentErrors) >= Retries, RecentErrors}.