Ulf Wiger
168 lines
4.4 KiB
Erlang
168 lines
4.4 KiB
Erlang
-module(gmhc_watchdog).
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-behavior(gen_server).
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-export([ watch/2
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, unwatch/0
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, ping/0 ]).
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-export([ note_started/2
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, remove_restart_info/1
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, get_restart_info/0 ]).
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-export([ start_link/0
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, init/1
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, handle_call/3
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, handle_cast/2
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, handle_info/2
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, terminate/2
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, code_change/3 ]).
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-record(st, {services = #{}}).
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-record(svc, { n = 5 :: pos_integer()
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, n0 = 5 :: pos_integer()
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, interval = 5000 :: pos_integer()
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, tref :: reference()
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, mref :: reference()
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}).
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-include_lib("kernel/include/logger.hrl").
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watch(Interval, N) ->
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gen_server:call(?MODULE, {watch, self(), Interval, N}).
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unwatch() ->
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gen_server:cast(?MODULE, {unwatch, self()}).
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ping() ->
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gen_server:cast(?MODULE, {ping, self()}).
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note_started(Id, Info) ->
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gen_server:call(?MODULE, {note_started, Id, Info}).
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get_restart_info() ->
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gen_server:call(?MODULE, get_restart_info).
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remove_restart_info([]) ->
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ok;
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remove_restart_info(IDs) ->
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gen_server:call(?MODULE, {remove_restart_info, IDs}).
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start_link() ->
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gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
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init([]) ->
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{ok, #st{}}.
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handle_call({note_started, Id, Info}, _From, S) ->
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update_pt(Id, Info),
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{reply, ok, S};
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handle_call({remove_restart_info, IDs}, _From, S) ->
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remove_restart_info_(IDs),
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{reply, ok, S};
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handle_call(get_restart_info, _From, S) ->
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{reply, get_pt(), S};
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handle_call({watch, Pid, Interval, N}, _From, S) ->
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{reply, ok, add_watch(Pid, Interval, N, S)};
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handle_call(_Req, _From, S) ->
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{reply, {error, unknown_method}, S}.
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handle_cast({ping, Pid}, S) ->
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{noreply, reset_watch(Pid, S)};
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handle_cast({unwatch, Pid}, S) ->
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{noreply, delete_watch(Pid, S)};
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handle_cast(Msg, S) ->
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?LOG_DEBUG("Unknown cast: ~p", [Msg]),
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{noreply, S}.
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handle_info({timeout, TRef, Pid}, S) ->
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?LOG_INFO("Timeout for pid ~p", [Pid]),
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{noreply, ping_timeout(Pid, TRef, S)};
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handle_info({'DOWN', _, process, Pid, _}, S) ->
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{noreply, delete_watch(Pid, S)};
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handle_info(Msg, S) ->
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?LOG_DEBUG("Unknown msg: ~p", [Msg]),
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{noreply, S}.
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terminate(_, _) ->
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ok.
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code_change(_FromVsn, S, _Extra) ->
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{ok, S}.
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add_watch(Pid, Interval, N, #st{services = Svcs} = S) ->
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MRef = erlang:monitor(process, Pid),
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Svc0 = #svc{ interval = Interval
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, mref = MRef
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, n = N
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, n0 = N},
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Svc = start_timer(Pid, Svc0),
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S#st{services = Svcs#{Pid => Svc}}.
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reset_watch(Pid, #st{services = Svcs} = S) ->
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case maps:find(Pid, Svcs) of
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{ok, #svc{ n0 = N0 } = Svc} ->
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Svc1 = restart_timer(Pid, Svc#svc{n = N0}),
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S#st{services = Svcs#{Pid := Svc1}};
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error ->
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S
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end.
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delete_watch(Pid, #st{services = Svcs} = S) ->
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case maps:find(Pid, Svcs) of
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{ok, #svc{tref = TRef, mref = MRef}} ->
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erlang:cancel_timer(TRef),
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erlang:demonitor(MRef),
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S#st{services = maps:remove(Pid, Svcs)};
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error ->
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S
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end.
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ping_timeout(Pid, TRef, #st{services = Svcs} = S) ->
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case maps:find(Pid, Svcs) of
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{ok, #svc{ n = N, tref = TRef} = Svc} ->
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N1 = N-1,
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if N1 =< 0 ->
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?LOG_ERROR("Will exit Pid ~p", [Pid]),
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exit(Pid, kill),
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S#st{services = maps:remove(Pid, Svcs)};
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true ->
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Svc1 = restart_timer(Pid, Svc#svc{n = N1}),
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S#st{services = Svcs#{Pid := Svc1}}
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end;
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{ok, _} ->
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?LOG_DEBUG("Timeout didn't match TRef - ignoring", []),
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S;
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_ ->
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S
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end.
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start_timer(Pid, #svc{interval = T} = Svc) ->
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TRef = erlang:start_timer(T, self(), Pid),
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Svc#svc{tref = TRef}.
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restart_timer(Pid, #svc{tref = TRef} = Svc) ->
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erlang:cancel_timer(TRef),
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start_timer(Pid, Svc#svc{tref = undefined}).
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update_pt(Id, Info) ->
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Pt = get_pt(),
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put_pt(Pt#{Id => Info}).
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remove_restart_info_(IDs) ->
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RI = get_pt(),
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case maps:without(IDs, RI) of
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RI ->
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ok;
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NewRI ->
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put_pt(NewRI)
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end.
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get_pt() ->
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persistent_term:get(pt_key(), #{}).
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put_pt(Pt) ->
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persistent_term:put(pt_key(), Pt).
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pt_key() ->
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{?MODULE, restart_info}.
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