%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2016. All Rights Reserved.
%%
%% 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.
%%
%% %CopyrightEnd%
%%
-module(snmpa_agent_sup).
-include("snmp_debug.hrl").
-behaviour(supervisor).
%% External exports
-export([start_link/0, start_link/1, start_subagent/3, stop_subagent/1]).
%% Internal exports
-export([init/1]).
-define(SERVER, ?MODULE).
%% Always use plain ets for sub-agents
-ifdef(snmp_debug).
-define(DEFAULT_SA_OPTS, [{mib_storage, [{module, snmpa_mib_storage_ets}]},
{verbosity, trace}]).
-else.
-define(DEFAULT_SA_OPTS, [{mib_storage, [{module, snmpa_mib_storage_ets}]}]).
-endif.
%%%-----------------------------------------------------------------
%%% This is a supervisor for the mib processes. Each agent has one
%%% mib process.
%%%-----------------------------------------------------------------
start_link() ->
?d("start_link -> entry", []),
supervisor:start_link({local, ?SERVER}, ?MODULE, [[]]).
start_link(AgentSpec) ->
?d("start_link -> entry with"
"~n AgentSpec: ~p", [AgentSpec]),
supervisor:start_link({local, ?SERVER}, ?MODULE, [[AgentSpec]]).
start_subagent(ParentAgent, Subtree, Mibs) ->
?d("start_subagent -> entry with"
"~n ParentAgent: ~p"
"~n Subtree: ~p"
"~n Mibs: ~p", [ParentAgent, Subtree, Mibs]),
Children = supervisor:which_children(?SERVER),
?d("start_subagent -> Children: ~n~p", [Children]),
Max = find_max(Children, 1),
?d("start_subagent -> Max: ~p", [Max]),
[{_, Prio}] = ets:lookup(snmp_agent_table, priority),
?d("start_subagent -> Prio: ~p", [Prio]),
Ref = make_ref(),
?d("start_subagent -> Ref: ~p", [Ref]),
Options = [{priority, Prio},
{mibs, Mibs},
{misc_sup, snmpa_misc_sup} | ?DEFAULT_SA_OPTS],
Agent = {{sub_agent, Max},
{snmpa_agent, start_link,
[Prio, ParentAgent, Ref, Options]},
permanent, 2000, worker, [snmpa_agent]},
case supervisor:start_child(?SERVER, Agent) of
{ok, SA} ->
?d("start_subagent -> SA: ~p", [SA]),
snmpa_agent:register_subagent(ParentAgent, Subtree, SA),
{ok, SA};
Error ->
?d("start_subagent -> Error: ~p", [Error]),
Error
end.
stop_subagent(SubAgentPid) ->
case find_name(supervisor:which_children(?SERVER), SubAgentPid) of
undefined ->
no_such_child;
Name ->
supervisor:terminate_child(?SERVER, Name),
supervisor:delete_child(?SERVER, Name),
ok
end.
init([Children]) ->
?d("init -> entry with"
"~n Children: ~p", [Children]),
%% 20 restarts in ten minutes. If the agent crashes and restarts,
%% it may very well crash again, because the management application
%% tries to resend the very same request. This depends on the resend
%% strategy used by the management application.
SupFlags = {one_for_one, 20, 600},
{ok, {SupFlags, Children}}.
find_max([{{sub_agent, N}, _, _, _} | T], M) when N >= M -> find_max(T, N+1);
find_max([_|T], M) -> find_max(T, M);
find_max([], M) -> M.
find_name([{Name, Pid, _, _} | _T], Pid)-> Name;
find_name([_|T], Pid) -> find_name(T, Pid);
find_name([], _Pid) -> undefined.
% i(F) ->
% i(F, []).
% i(F, A) ->
% io:format("~p:~p: " ++ F ++ "~n", [node(),?MODULE|A]).
