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% 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_jobs_activity_monitor).
-behaviour(gen_server).
-export([
start_link/1
]).
-export([
init/1,
terminate/2,
handle_call/3,
handle_cast/2,
handle_info/2,
code_change/3
]).
-record(st, {
jtx,
type,
tref,
timeout = 0,
vs = not_found
}).
-define(MAX_JITTER_DEFAULT, 10000).
-define(MISSING_TIMEOUT_CHECK, 5000).
start_link(Type) ->
gen_server:start_link(?MODULE, [Type], []).
%% gen_server callbacks
init([Type]) ->
St = #st{jtx = couch_jobs_fdb:get_jtx(), type = Type},
{ok, schedule_check(St)}.
terminate(_, _St) ->
ok.
handle_call(Msg, _From, St) ->
{stop, {bad_call, Msg}, {bad_call, Msg}, St}.
handle_cast(Msg, St) ->
{stop, {bad_cast, Msg}, St}.
handle_info(check_activity, St) ->
St1 = try
check_activity(St)
catch
error:{erlfdb_error, Err} when Err =:= 1020 orelse Err =:= 1031 ->
LogMsg = "~p : type:~p got ~p error, possibly from overload",
couch_log:error(LogMsg, [?MODULE, St#st.type, Err]),
St
end,
St2 = schedule_check(St1),
{noreply, St2};
handle_info({Ref, ready}, St) when is_reference(Ref) ->
% Don't crash out couch_jobs_server and the whole application would need to
% eventually do proper cleanup in erlfdb:wait timeout code.
LogMsg = "~p : spurious erlfdb future ready message ~p",
couch_log:error(LogMsg, [?MODULE, Ref]),
{noreply, St};
handle_info(Msg, St) ->
{stop, {bad_info, Msg}, St}.
code_change(_OldVsn, St, _Extra) ->
{ok, St}.
% Private helper functions
check_activity(#st{jtx = JTx, type = Type, vs = not_found} = St) ->
NewVS = couch_jobs_fdb:tx(JTx, fun(JTx1) ->
couch_jobs_fdb:get_activity_vs(JTx1, Type)
end),
St#st{vs = NewVS};
check_activity(#st{jtx = JTx, type = Type, vs = VS} = St) ->
NewVS = couch_jobs_fdb:tx(JTx, fun(JTx1) ->
NewVS = couch_jobs_fdb:get_activity_vs(JTx1, Type),
JobIds = couch_jobs_fdb:get_inactive_since(JTx1, Type, VS),
couch_jobs_fdb:re_enqueue_inactive(JTx1, Type, JobIds),
NewVS
end),
St#st{vs = NewVS}.
get_timeout_msec(JTx, Type) ->
TimeoutVal = couch_jobs_fdb:tx(JTx, fun(JTx1) ->
couch_jobs_fdb:get_type_timeout(JTx1, Type)
end),
case TimeoutVal of
not_found -> not_found;
ValSeconds -> timer:seconds(ValSeconds)
end.
schedule_check(#st{jtx = JTx, type = Type, timeout = OldTimeout} = St) ->
% Reset versionstamp if timeout changed.
St1 = case get_timeout_msec(JTx, Type) of
not_found ->
St#st{vs = not_found, timeout = ?MISSING_TIMEOUT_CHECK};
OldTimeout ->
St;
NewTimeout ->
St#st{vs = not_found, timeout = NewTimeout}
end,
#st{timeout = Timeout} = St1,
MaxJitter = min(Timeout div 2, get_max_jitter_msec()),
Wait = Timeout + rand:uniform(max(1, MaxJitter)),
St1#st{tref = erlang:send_after(Wait, self(), check_activity)}.
get_max_jitter_msec()->
config:get_integer("couch_jobs", "activity_monitor_max_jitter_msec",
?MAX_JITTER_DEFAULT).
|
