Add retrieving flow tables' identifiers from dobby

When publishing a Net Flow the dobby_oflib creates links between
Flow Mods and corresponding Flow Tables. To accomplish that flow tables'
identifiers are needed.

Author: Szymon Mentel

src/dofl_identifier.erl

@@ -35,11 +35,23 @@ flow_mod(Dpid, OFVersion, FlowMod) ->
     {Cookie, #{type => of_flow_mod, dpid => Dpid, of_version => OFVersion}}.
 
 
--spec flow_table(Dpid :: binary(), FlowMod :: flow_mod())
+-spec flow_table(DatapathId :: binary(), FlowMod :: flow_mod())
                 -> FlowTableId :: idenfier().
 
-flow_table(Dpid, FlowMod) ->
-    <<Dpid/binary>>.
+flow_table(DatapahtId, {_Matches, _Actions, Opts}) ->
+    TableNo = proplists:get_value(table_id, Opts),
+    TableIdFun =
+        fun(Dpid, _, undefined, []) ->
+                {continue, Dpid};
+           (Identifier, IdMetadata, _LinkMetadata, Dpid) ->
+                case [maps:get(P, IdMetadata) || P <- [type, table_no]] of
+                    [of_flow_table, TableNo] ->
+                        {stop, Identifier};
+                    _ ->
+                        {skip, Dpid}
+                end
+        end,
+    dby:search(TableIdFun, [], DatapahtId, [breadth,{max_depth, 1}]).
 
 %%%=============================================================================
 %%% Internal functions

test/dobby_oflib_SUITE.erl

@@ -30,6 +30,7 @@ init_per_suite(Config) ->
 
 end_per_suite(_Config) ->
     unmock_dobby(),
+    unmock_flow_table_identifiers(),
     ok.
 
 all() ->
@@ -116,6 +117,9 @@ mock_flow_table_identifiers() ->
                              <<Dpid/binary, ":", TableNoBin/binary>>
                      end).
 
+unmock_flow_table_identifiers() ->
+    ok = meck:unload(dofl_identifier).
+
 flow_mod_identifier({Dpid, OFVersion, _FlowTableId, FlowMod}) ->
     {_Matches, _Instructions, Opts} = FlowMod,
     Cookie = proplists:get_value(cookie, Opts),
@@ -130,7 +134,6 @@ link_metadata(Type, {NetFlowId, Src}) ->
 link_metadata(Type, bidirectional) ->
     #{type => Type}.
 
-
 reconstruct_flow_path(FlowPath0) ->
     Fun = fun({Dpid, {OFVersion, FlowMods}}) ->
                   [reconstruct_flow_mod(Dpid, OFVersion, FM) || FM <- FlowMods]

test/dofl_identifier_SUITE.erl

@@ -0,0 +1,71 @@
+%%%=============================================================================
+%%% @copyright (C) 2015, Erlang Solutions Ltd
+%%% @author Szymon Mentel <szymon.mentel@erlang-solutions.com>
+%%% @doc <Suite purpose>
+%%% @end
+%%%=============================================================================
+-module(dofl_identifier_SUITE).
+-copyright("2015, Erlang Solutions Ltd.").
+
+%% Note: This directive should only be used in test suites.
+-compile(export_all).
+-include_lib("common_test/include/ct.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+-define(TABLE_IDENTIFIER, <<"TableId">>).
+-define(DPID, <<"00:00:00:00:00:01:00:01">>).
+
+%%%=============================================================================
+%%% Callbacks
+%%%=============================================================================
+
+
+suite() ->
+    [{timetrap,{minutes,10}}].
+
+init_per_suite(Config) ->
+    mock_dobby(),
+    Config.
+
+end_per_suite(_Config) ->
+    unmock_dobby(),
+    ok.
+
+all() ->
+    [should_query_flow_table_id].
+
+%%%=============================================================================
+%%% Testcases
+%%%=============================================================================
+
+should_query_flow_table_id(_Config) ->
+    %% GIVEN
+    FlowMod = dofl_test_utils:flow_mod(),
+    TableNo = dofl_test_utils:flow_mod_to_table_no(FlowMod),
+
+    %% WHEN
+    dofl_identifier:flow_table(?DPID, FlowMod),
+
+    %% THEN
+    assert_dobby_search_fun_correct(?DPID, TableNo).
+
+%%%=============================================================================
+%%% Internal functions
+%%%=============================================================================
+
+mock_dobby() ->
+    ok = meck:expect(dby, search, 4, _Ret = ?TABLE_IDENTIFIER).
+unmock_dobby() ->
+    ok = meck:unload(dby).
+
+assert_dobby_search_fun_correct(Dpid, TableNo) ->
+    SearchFun = meck:capture(first, dby, search, ['_', '_', Dpid, '_'],
+                             _ArgNo = 1),
+    NullLink = {Dpid, null, undefined},
+    SearchResult = SearchFun(?TABLE_IDENTIFIER,
+                             #{type => of_flow_table, table_no => TableNo},
+                             #{type => of_resource},
+                             [NullLink]),
+    ?assertEqual({stop, ?TABLE_IDENTIFIER}, SearchResult).
+
+

test/dofl_test_utils.erl

@@ -10,7 +10,9 @@
 %% API
 -export([figure4/0,
          flow_path/0,
-         flow_path_to_identifiers/1]).
+         flow_path_to_identifiers/1,
+         flow_mod/0,
+         flow_mod_to_table_no/1]).
 
 -include_lib("eunit/include/eunit.hrl").
 
@@ -61,6 +63,17 @@ flow_path() ->
           {cookie_mask, <<0,0,0,0,0,0,0,0>>}]}]}
      }].
 
+flow_mod() ->
+    {[{in_port,2}],
+     [{apply_actions,[{output,1,no_buffer}]}],
+     [{table_id, 0}, {priority, 100},
+      {idle_timeout, 0}, {idle_timeout, 0},
+      {cookie, <<0,0,0,0,0,0,0,102>>},
+      {cookie_mask, <<0,0,0,0,0,0,0,0>>}]}.
+
+flow_mod_to_table_no({_Matches, _Actions, Opts}) ->
+    proplists:get_value(table_id, Opts).
+
 %% @doc
 %% Transletes `FlowPath' as returned by ?MODULE:figure4() into a list
 %% of subsequent identifiers.