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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(custodian_db_checker).
-behaviour(gen_server).
-vsn(1).
-export([start_link/0]).
-export([
init/1,
terminate/2,
handle_call/3,
handle_cast/2,
handle_info/2,
code_change/3
]).
-export([
check_dbs/0
]).
-record(st, {
checker
}).
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
init(_) ->
process_flag(trap_exit, true),
net_kernel:monitor_nodes(true),
{ok, restart_checker(#st{})}.
terminate(_Reason, St) ->
couch_util:shutdown_sync(St#st.checker),
ok.
handle_call(Msg, _From, St) ->
{stop, {invalid_call, Msg}, {invalid_call, Msg}, St}.
handle_cast(refresh, St) ->
{noreply, restart_checker(St)};
handle_cast(Msg, St) ->
{stop, {invalid_cast, Msg}, St}.
handle_info({nodeup, _}, St) ->
{noreply, restart_checker(St)};
handle_info({nodedown, _}, St) ->
{noreply, restart_checker(St)};
handle_info({'EXIT', Pid, normal}, #st{checker=Pid}=St) ->
{noreply, St#st{checker=undefined}};
handle_info({'EXIT', Pid, Reason}, #st{checker=Pid}=St) ->
couch_log:notice("custodian db checker died ~p", [Reason]),
{noreply, restart_checker(St#st{checker=undefined})};
handle_info(Msg, St) ->
{stop, {invalid_info, Msg}, St}.
code_change(_OldVsn, St, _Extra) ->
{ok, St}.
restart_checker(#st{checker=undefined}=St) ->
Pid = spawn_link(fun ?MODULE:check_dbs/0),
St#st{checker=Pid};
restart_checker(#st{checker=Pid}=St) when is_pid(Pid) ->
St.
check_dbs() ->
{ok, DbsDb} = custodian_util:ensure_dbs_exists(),
try
Missing = lists:foldl(fun(DbName, Count) ->
case check_db(DbsDb, DbName) of
ok -> Count;
missing -> Count + 1
end
end, 0, get_dbs()),
case Missing == 0 of
true -> clear_missing_dbs_alert();
false -> ok
end
after
couch_db:close(DbsDb)
end.
check_db(DbsDb, DbName) when is_binary(DbName) ->
try
case couch_db:open_doc(DbsDb, DbName, []) of
{ok, _} ->
ok;
_ ->
send_missing_db_alert(DbName),
missing
end
catch _:_ ->
send_missing_db_alert(DbName),
missing
end.
get_dbs() ->
lists:flatten([
get_users_db(),
get_stats_db()
]).
get_users_db() ->
UsersDb = config:get("couch_httpd_auth", "authentication_db", "users"),
[list_to_binary(UsersDb)].
get_stats_db() ->
case application:get_env(ioq, stats_db) of
{ok, DbName} when is_binary(DbName) ->
[DbName];
{ok, DbName} when is_list(DbName) ->
[iolist_to_binary(DbName)];
_ ->
[]
end.
send_missing_db_alert(DbName) ->
couch_log:notice("Missing system database ~s", [DbName]),
?CUSTODIAN_MONITOR:send_missing_db_alert(DbName).
clear_missing_dbs_alert() ->
couch_log:notice("All system databases exist.", []),
?CUSTODIAN_MONITOR:clear_missing_dbs_alert().
|
