%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2013-2013. 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_mib_storage_mnesia).
-behaviour(snmpa_mib_storage).
%%%-----------------------------------------------------------------
%%% This module implements the snmpa_mib_storage behaviour.
%%% It uses mnesia for storage.
%%%-----------------------------------------------------------------
-export([
open/5,
close/1,
read/2,
write/2,
delete/1,
delete/2,
match_object/2,
match_delete/2,
tab2list/1,
info/1, info/2,
sync/1,
backup/2
]).
-define(VMODULE,"MS-MNESIA").
-include("snmp_verbosity.hrl").
-record(tab, {id}).
%% ---------------------------------------------------------------
%% open
%%
%% Open or create a mnesia table.
%%
%% Opts - A list of implementation dependent options
%% mnesia_open_options() = [mnesia_open_option()]
%% mnesia_open_option() = {action, keep | clear} |
%% {nodes, [node()]}
%%
%% ---------------------------------------------------------------
open(Name, RecName, Fields, Type, Opts) ->
?vtrace("open ~p table ~p for record ~p",
[Type, Name, RecName]),
Action = get_action(Opts),
Nodes = get_nodes(Opts),
case table_exists(Name) of
true when (Action =:= keep) ->
?vtrace("open table ~p - exist (keep)", [Name]),
{ok, #tab{id = Name}};
true when (Action =:= clear) ->
?vtrace("open table ~p - exist (clear)", [Name]),
F = fun() -> mnesia:clear_table(Name) end,
case mnesia:transaction(F) of
{aborted, Reason} ->
{error, {clear, Reason}};
{atomic, _} ->
{ok, #tab{id = Name}}
end;
false ->
?vtrace("open table ~p - does not exist", [Name]),
Args = [{record_name, RecName},
{attributes, Fields},
{type, Type},
{disc_copies, Nodes}],
case mnesia:create_table(Name, Args) of
{atomic, ok} ->
?vtrace("open table ~p - ok", [Name]),
{ok, #tab{id = Name}};
{aborted, Reason} ->
?vinfo("open table ~p - aborted"
"~n Reason: ~p", [Name, Reason]),
{error, {create, Reason}}
end
end.
table_exists(Name) ->
case (catch mnesia:table_info(Name, type)) of
{'EXIT', _Reason} ->
false;
_ ->
true
end.
%% ---------------------------------------------------------------
%% close
%%
%% Close the mib-storage table.
%% This does nothing in the mnesia case.
%% ---------------------------------------------------------------
close(_) ->
?vtrace("close mib-storage - ignore",[]),
ok.
%% ---------------------------------------------------------------
%% read
%%
%% Retrieve a record from the mib-storage table.
%% ---------------------------------------------------------------
read(#tab{id = ID}, Key) ->
?vtrace("read (dirty) from database ~p: ~p", [ID, Key]),
case (catch mnesia:dirty_read(ID, Key)) of
[Rec|_] -> {value,Rec};
_ -> false
end.
%% ---------------------------------------------------------------
%% write
%%
%% Write a record to the mib-storage table.
%% ---------------------------------------------------------------
write(#tab{id = ID}, Rec) ->
?vtrace("write to database ~p", [ID]),
F = fun() -> mnesia:write(ID, Rec, write) end,
case mnesia:transaction(F) of
{aborted, _Reason} = ABORTED ->
{error, ABORTED};
{atomic,_} ->
ok
end.
%% ---------------------------------------------------------------
%% delete
%%
%% Delete the mib-storage table.
%% ---------------------------------------------------------------
delete(#tab{id = ID}) ->
?vtrace("delete database: ~p", [ID]),
mnesia:delete_table(ID).
%% ---------------------------------------------------------------
%% delete
%%
%% Delete a record from the mib-storage table.
%% ---------------------------------------------------------------
delete(#tab{id = ID}, Key) ->
?vtrace("delete from database ~p: ~p", [ID, Key]),
F = fun() -> mnesia:delete(ID, Key, write) end,
case mnesia:transaction(F) of
{aborted, _Reason} = ABORTED ->
{error, ABORTED};
{atomic, _} ->
ok
end.
%% ---------------------------------------------------------------
%% match_object
%%
%% Search the mib-storage table for records witch matches
%% the pattern.
%% ---------------------------------------------------------------
match_object(#tab{id = ID}, Pattern) ->
?vtrace("match_object in ~p of ~p", [ID, Pattern]),
F = fun() -> mnesia:match_object(ID, Pattern, read) end,
case mnesia:transaction(F) of
{aborted, _Reason} = ABORTED ->
{error, ABORTED};
{atomic, Rs} ->
Rs
end.
%% ---------------------------------------------------------------
%% match_delete
%%
%% Search the mib-storage table for records witch matches
%% the pattern and deletes them from the table.
%% ---------------------------------------------------------------
match_delete(#tab{id = ID}, Pattern) ->
?vtrace("match_delete in ~p with pattern ~p", [ID, Pattern]),
F = fun() ->
Recs = mnesia:match_object(ID, Pattern, read),
lists:foreach(fun(Rec) ->
mnesia:delete_object(ID, Rec, write)
end, Recs),
Recs
end,
case mnesia:transaction(F) of
{aborted, _Reason} = ABORTED ->
{error, ABORTED};
{atomic, Rs} ->
Rs
end.
%% ---------------------------------------------------------------
%% tab2list
%%
%% Return all records in the mib-storage table in the form of
%% a list.
%% ---------------------------------------------------------------
tab2list(#tab{id = ID} = Tab) ->
?vtrace("tab2list -> list of ~p", [ID]),
match_object(Tab, mnesia:table_info(ID, wild_pattern)).
%% ---------------------------------------------------------------
%% info
%%
%% Retrieve implementation dependent mib-storage table
%% information.
%% ---------------------------------------------------------------
info(#tab{id = ID}) ->
case (catch mnesia:table_info(ID, all)) of
Info when is_list(Info) ->
Info;
{'EXIT', {aborted, Reason}} ->
{error, Reason}
end.
info(#tab{id = ID}, Item) ->
mnesia:table_info(ID, Item).
%% ---------------------------------------------------------------
%% sync
%%
%% Ignore
%% ---------------------------------------------------------------
sync(_) ->
ok.
%% ---------------------------------------------------------------
%% backup
%%
%% Ignore. Mnesia handles its own backups.
%% ---------------------------------------------------------------
backup(_, _) ->
ok.
%%----------------------------------------------------------------------
get_action(Opts) ->
snmp_misc:get_option(action, Opts, keep).
get_nodes(Opts) ->
case snmp_misc:get_option(nodes, Opts, erlang:nodes()) of
[] ->
[node()];
Nodes when is_list(Nodes) ->
Nodes;
all ->
erlang:nodes();
visible ->
erlang:nodes(visible);
connected ->
erlang:nodes(connected);
db_nodes ->
try mnesia:system_info(db_nodes) of
DbNodes when is_list(DbNodes) ->
DbNodes;
_ ->
erlang:nodes()
catch
_:_ ->
erlang:nodes()
end
end.
%% user_err(F, A) ->
%% snmpa_error:user_err(F, A).
