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/*
*
* 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/iomgr/sockaddr_utils.h"
#include "src/core/lib/support/string.h"
grpc_channel* grpc_lb_policy_grpclb_create_lb_channel(
grpc_exec_ctx* exec_ctx, 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(
exec_ctx, 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_exec_ctx* exec_ctx, grpc_slice_hash_table* targets_info,
grpc_fake_resolver_response_generator* response_generator,
const grpc_channel_args* args) {
const grpc_arg to_add[] = {
grpc_fake_resolver_response_generator_arg(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));
}
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