Pick the specify worker

src/grpcbox_channel.erl

@@ -4,6 +4,7 @@
 
 -export([start_link/3,
          is_ready/1,
+         get/3,
          pick/2,
          pick/3,
          add_endpoints/2,
@@ -57,6 +58,16 @@ start_link(Name, Endpoints, Options) ->
 is_ready(Name) ->
     gen_statem:call(?CHANNEL(Name), is_ready).
 
+-spec get(name(), unary | stream, term()) ->
+    {ok, {pid(), grpcbox_client:interceptor() | undefined}} |
+    {error, undefined_channel | not_found_endpoint}.
+get(Name, CallType, Key) ->
+    case lists:keyfind(Key, 1, gproc_pool:active_workers(Name)) of
+        {_, Pid} -> {ok, {Pid, interceptor(Name, CallType)}};
+        false -> {error, not_found_endpoint}
+    end.
+
+
 %% @doc Picks a subchannel from a pool using the configured strategy.
 -spec pick(name(), unary | stream) ->
     {ok, {pid(), grpcbox_client:interceptor() | undefined}} |

src/grpcbox_client.erl

@@ -50,6 +50,7 @@ get_channel(Options, Type) ->
     Key =  maps:get(key, Options, undefined),
     PickStrategy =  maps:get(pick_strategy, Options, undefined),
     case PickStrategy of
+        specify_worker -> grpcbox_channel:get(Channel, Type, Key);
         active_worker ->  grpcbox_channel:pick({Channel, active}, Type, Key);
         undefined -> grpcbox_channel:pick(Channel, Type, Key)
     end.

test/grpcbox_channel_SUITE.erl

@@ -6,7 +6,8 @@
         add_and_remove_endpoints/1,
         add_and_remove_endpoints_active_workers/1,
         pick_worker_strategy/1,
-        pick_active_worker_strategy/1]).
+        pick_active_worker_strategy/1,
+        pick_specify_worker_strategy/1]).
 
 -include_lib("eunit/include/eunit.hrl").
 
@@ -15,7 +16,8 @@ all() ->
         add_and_remove_endpoints,
         add_and_remove_endpoints_active_workers,
         pick_worker_strategy,
-        pick_active_worker_strategy
+        pick_active_worker_strategy,
+        pick_specify_worker_strategy
     ].
 init_per_suite(_Config) ->
     GrpcOptions = #{service_protos => [route_guide_pb], services => #{'routeguide.RouteGuide' => routeguide_route_guide}},
@@ -95,6 +97,13 @@ pick_active_worker_strategy(_Config) ->
     ?assertEqual(error, pick_worker({direct_channel, active})),
     ?assertEqual(error, pick_worker({hash_channel, active})),
     ok.
+
+pick_specify_worker_strategy(_Config) ->
+    ?assertMatch({ok, _} ,grpcbox_channel:get(default_channel, stream, {http, "127.0.0.1", 18080, #{}})),
+    ?assertEqual({error, not_found_endpoint} ,grpcbox_channel:get(default_channel, stream, {http, "127.0.0.1", 8080, #{}})),
+    ?assertEqual({error, not_found_endpoint} ,grpcbox_channel:get(channel_xxx, stream, {http, "127.0.0.1", 8080, #{}})),
+    ok.
+
 pick_worker(Name, N) ->
     {R, _} = grpcbox_channel:pick(Name, unary, N),
     R.