impr: Allow to receive multiple /block/current requests and use highest height.

src/core/resolver/hb_opts.erl

@@ -426,6 +426,23 @@ raw_default_message() ->
                         <<"opts">> => ?DEFAULT_HTTP_OPTS
                     }
             },
+            % Wait for 2 node responses when fetching current block or height information
+            #{
+                <<"template">> => <<"^/arweave/block/current">>,
+                <<"nodes">> => add_opts(?ARWEAVE_BOOTSTRAP_CHAIN_NODES),
+                <<"parallel">> => true,
+                <<"responses">> => 2,
+                <<"stop-after">> => true,
+                <<"admissible-status">> => 200
+            },
+            #{
+                <<"template">> => <<"^/arweave/height">>,
+                <<"nodes">> => add_opts(?ARWEAVE_BOOTSTRAP_CHAIN_NODES),
+                <<"parallel">> => true,
+                <<"responses">> => 2,
+                <<"stop-after">> => true,
+                <<"admissible-status">> => 200
+            },
             % General Arweave requests: race all chain nodes, take
             % the first 200.
             #{

src/preloaded/arweave/dev_arweave.erl

@@ -885,10 +885,19 @@ request(Method, Path, Extra, LogExtra, Opts) ->
                 <<"cache-control">> => [<<"no-cache">>, <<"no-store">>]
             }
         ),
-    to_message(Path, Method, best_response(Res), LogExtra, Opts).
+    to_message(Path, Method, best_response(Path, Res), LogExtra, Opts).
 
 %% @doc Select the best response from a list of responses by sorting them
 %% ascending by HTTP status code. Returns the first (best) response tuple.
+best_response(Path, {error, {no_viable_responses, Responses}}) ->
+    best_response(Path, Responses);
+best_response(<<"/height">>, Responses) when is_list(Responses) ->
+    current_height_best_response(current_height_responses(Responses));
+best_response(<<"/block/current">>, Responses) when is_list(Responses) ->
+    current_height_best_response(current_height_responses(Responses));
+best_response(_Path, Response) ->
+    best_response(Response).
+
 best_response({error, {no_viable_responses, Responses}}) ->
     best_response(Responses);
 best_response([]) ->
@@ -911,6 +920,47 @@ response_status(Response) when is_map(Response) ->
 response_status(_Response) ->
     999.
 
+%% @doc Parse responses that contains block height to return the one with the
+%% highest value. This helps when one node lags behind.
+current_height_responses(Responses) ->
+    lists:filtermap(
+        fun
+            ({ok, #{ <<"body">> := Body }} = Response) ->
+                try hb_json:decode(Body) of
+                    #{ <<"height">> := Height } ->
+                        {true, {hb_util:int(Height), Response}};
+                    Height when is_integer(Height) ->
+                        {true, {Height, Response}};
+                    _ ->
+                        false
+                catch _:_ ->
+                    case hb_util:safe_int(Body) of
+                        {ok, Height} -> {true, {Height, Response}};
+                        {error, invalid} -> false
+                    end
+                end;
+            (_) ->
+                false
+        end,
+        Responses
+    ).
+
+current_height_best_response([]) ->
+    {error, no_viable_responses};
+current_height_best_response([{Height, Response} | Rest]) ->
+    {_, BestResponse} =
+        lists:foldl(
+            fun({NextHeight, NextResponse}, {BestHeight, Best}) ->
+                case NextHeight > BestHeight of
+                    true -> {NextHeight, NextResponse};
+                    false -> {BestHeight, Best}
+                end
+            end,
+            {Height, Response},
+            Rest
+        ),
+    BestResponse.
+
 %% @doc Transform a response from the Arweave node into an AO-Core message.
 to_message(Path, Method, {error, #{ <<"status">> := 404 }}, LogExtra, _Opts) ->
     event_request(Path, Method, 404, LogExtra),
@@ -1209,6 +1259,16 @@ best_response_handles_failed_connect_entries_test_parallel() ->
         best_response(Responses)
     ).
 
+best_response_height_integer_body_test_parallel() ->
+    Responses = [
+        {ok, #{ <<"status">> => 200, <<"body">> => <<"5">> }},
+        {ok, #{ <<"status">> => 200, <<"body">> => <<"8">> }}
+    ],
+    ?assertEqual(
+        {ok, #{ <<"status">> => 200, <<"body">> => <<"8">> }},
+        best_response(<<"/height">>, Responses)
+    ).
+
 best_response_non_map_error_round_trips_test_parallel() ->
     FailedConnect =
         {failed_connect,

src/preloaded/query/dev_copycat_arweave.erl

@@ -1361,6 +1361,48 @@ latest_height_failure_test_parallel() ->
         hb_mock_server:stop(MockHandle)
     end.
 
+latest_height_uses_highest_mockserver_height_test_parallel() ->
+    {ok, MockURL1, MockHandle1} = hb_mock_server:start([
+        {"/block/current", block_current, {200, <<"{\"height\": 5}">>}}
+    ]),
+    {ok, MockURL2, MockHandle2} = hb_mock_server:start([
+        {"/block/current", block_current, {200, <<"{\"height\": 8}">>}}
+    ]),
+    TestStore = hb_test_utils:test_store(),
+    Opts = #{
+        <<"store">> => [TestStore],
+        <<"arweave-index-blocks">> => false,
+        <<"routes">> => [
+            #{
+                <<"template">> => <<"^/arweave">>,
+                <<"nodes">> => [
+                    #{
+                        <<"match">> => <<"^/arweave">>,
+                        <<"with">> => MockURL1,
+                        <<"opts">> => #{ <<"http-client">> => httpc }
+                    },
+                    #{
+                        <<"match">> => <<"^/arweave">>,
+                        <<"with">> => MockURL2,
+                        <<"opts">> => #{ <<"http-client">> => httpc }
+                    }
+                ],
+                <<"parallel">> => false,
+                <<"responses">> => 2,
+                <<"stop-after">> => false,
+                <<"admissible-status">> => 200
+            }
+        ]
+    },
+    try
+        ?assertEqual({ok, 8}, latest_height(Opts)),
+        [_] = hb_mock_server:get_requests(block_current, 1, MockHandle1),
+        [_] = hb_mock_server:get_requests(block_current, 1, MockHandle2)
+    after
+        hb_mock_server:stop(MockHandle1),
+        hb_mock_server:stop(MockHandle2)
+    end.
+
 negative_resolved_height_test_parallel() ->
     {ok, MockURL, MockHandle} = hb_mock_server:start([
         {"/block/current", block_current,