| /* |
| * |
| * Copyright 2017 gRPC authors. |
| * |
| * 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. |
| * |
| */ |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/string_util.h> |
| |
| #include "src/core/ext/filters/client_channel/client_channel.h" |
| #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h" |
| #include "src/core/lib/channel/channel_args.h" |
| #include "src/core/lib/gpr/string.h" |
| #include "src/core/lib/iomgr/sockaddr_utils.h" |
| |
| grpc_channel* grpc_lb_policy_grpclb_create_lb_channel( |
| const char* lb_service_target_addresses, |
| grpc_client_channel_factory* client_channel_factory, |
| grpc_channel_args* args) { |
| grpc_channel* lb_channel = grpc_client_channel_factory_create_channel( |
| client_channel_factory, lb_service_target_addresses, |
| GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, args); |
| return lb_channel; |
| } |
| |
| grpc_channel_args* grpc_lb_policy_grpclb_build_lb_channel_args( |
| grpc_slice_hash_table* targets_info, |
| grpc_core::FakeResolverResponseGenerator* response_generator, |
| const grpc_channel_args* args) { |
| const grpc_arg to_add[] = { |
| grpc_core::FakeResolverResponseGenerator::MakeChannelArg( |
| response_generator)}; |
| /* We remove: |
| * |
| * - The channel arg for the LB policy name, since we want to use the default |
| * (pick_first) in this case. |
| * |
| * - The channel arg for the resolved addresses, since that will be generated |
| * by the name resolver used in the LB channel. Note that the LB channel |
| * will use the fake resolver, so this won't actually generate a query |
| * to DNS (or some other name service). However, the addresses returned by |
| * the fake resolver will have is_balancer=false, whereas our own |
| * addresses have is_balancer=true. We need the LB channel to return |
| * addresses with is_balancer=false so that it does not wind up recursively |
| * using the grpclb LB policy, as per the special case logic in |
| * client_channel.c. |
| * |
| * - The channel arg for the server URI, since that will be different for the |
| * LB channel than for the parent channel (the client channel factory will |
| * re-add this arg with the right value). |
| * |
| * - The fake resolver generator, because we are replacing it with the one |
| * from the grpclb policy, used to propagate updates to the LB channel. */ |
| static const char* keys_to_remove[] = { |
| GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI, |
| GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR}; |
| return grpc_channel_args_copy_and_add_and_remove( |
| args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), to_add, |
| GPR_ARRAY_SIZE(to_add)); |
| } |