blob: cac031a9bf4eb90345a2ca195c3bd493ecc5f596 [file] [log] [blame]
% 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
% 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.
-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]).
-record(daemon, {
-define(PORT_OPTIONS, [stream, {line, 1024}, binary, exit_status, hide]).
-define(TIMEOUT, 5000).
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
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 ?MODULE:config_change/2),
Table = ets:new(?MODULE, [protected, set, {keypos, #daemon.port}]),
{ok, Table}.
terminate(_Reason, Table) ->
[stop_port(D) || D <- ets:tab2list(Table)],
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}
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
{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])
{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.", []),
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, [, 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, [, 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}
_Else ->
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]),
{ok, D3} = handle_port_message(D, JSON),
true = ets:insert(Table, D2#daemon{buf=[]})
{noreply, Table};
handle_info({Port, Error}, Table) ->
?LOG_ERROR("Unexpectd message from port ~p: ~p", [Port, Error]),
[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) ->
start_port(Command, []).
start_port(Command, EnvPairs) ->
PrivDir = couch_util:priv_dir(),
Spawnkiller = filename:join(PrivDir, "couchspawnkillable"),
Opts = case lists:keytake(env, 1, ?PORT_OPTIONS) of
false ->
?PORT_OPTIONS ++ [ {env,EnvPairs} ];
{value, {env,OldPairs}, SubOpts} ->
AllPairs = lists:keymerge(1, EnvPairs, OldPairs),
SubOpts ++ [ {env,AllPairs} ]
Port = open_port({spawn, Spawnkiller ++ " " ++ Command}, Opts),
{ok, Port}.
stop_port(#daemon{port=Port, kill=undefined}=D) ->
?LOG_ERROR("Stopping daemon without a kill command: ~p", []),
catch port_close(Port);
stop_port(#daemon{port=Port}=D) ->
?LOG_DEBUG("Stopping daemon: ~p", []),
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, <<Json/binary, "\n">>),
{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)
Json = iolist_to_binary(?JSON_ENCODE(Value)),
port_command(Port, <<Json/binary, "\n">>),
{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='$2', status=running, _='_'},
Running = lists:sort([{N, C} || [N, C] <- ets:match(Table, MSpecRunning)]),
ok = stop_os_daemons(Table, find_to_stop(Configured, Running, [])),
ok = boot_os_daemons(Table, find_to_boot(Configured, Running, [])),
restart_daemons(Table, Sect, Key) ->
restart_daemons(Table, Sect, Key, ets:first(Table)).
restart_daemons(_, _, _, '$end_of_table') ->
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 ->
D2 = D#daemon{status=restarting, buf=nil},
true = ets:insert(Table, D2);
_ ->
restart_daemons(Table, Sect, Key, ets:next(Table, Port)).
stop_os_daemons(_Table, []) ->
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);
_ ->
D2 = D#daemon{status=stopping, errors=nil, buf=nil},
true = ets:insert(Table, D2)
stop_os_daemons(Table, Rest).
boot_os_daemons(_Table, []) ->
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.
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.
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}.