int NacosNamingService::GetServerNodes()

in src/brpc/policy/nacos_naming_service.cpp [108:233]
110 lines of code
30 McCabe index (conditional complexity)

int NacosNamingService::GetServerNodes(const char *service_name,
                                       bool token_changed,
                                       std::vector<ServerNode> *nodes) {
    if (_nacos_url.empty() || token_changed) {
        _nacos_url = FLAGS_nacos_service_discovery_path;
        _nacos_url += "?";
        if (!_access_token.empty()) {
            _nacos_url += "accessToken=" + _access_token;
            _nacos_url += "&";
        }
        _nacos_url += service_name;
    }

    Controller cntl;
    cntl.http_request().uri() = _nacos_url;
    _channel.CallMethod(nullptr, &cntl, nullptr, nullptr, nullptr);
    if (cntl.Failed()) {
        LOG(ERROR) << "Fail to access " << _nacos_url << ": "
                   << cntl.ErrorText();
        return -1;
    }
    if (cntl.http_response().status_code() != HTTP_STATUS_OK) {
        LOG(ERROR) << "Failed to request nacos, http status code: "
                   << cntl.http_response().status_code();
        return -1;
    }

    BUTIL_RAPIDJSON_NAMESPACE::Document doc;
    if (doc.Parse(cntl.response_attachment().to_string().c_str())
            .HasParseError()) {
        LOG(ERROR) << "Failed to parse nacos response";
        return -1;
    }
    if (!doc.IsObject()) {
        LOG(ERROR) << "The nacos's response for " << service_name
                   << " is not a json object";
        return -1;
    }

    auto it_hosts = doc.FindMember("hosts");
    if (it_hosts == doc.MemberEnd()) {
        LOG(ERROR) << "The nacos's response for " << service_name
                   << " has no hosts member";
        return -1;
    }
    auto &hosts = it_hosts->value;
    if (!hosts.IsArray()) {
        LOG(ERROR) << "hosts member in nacos response is not an array";
        return -1;
    }

    std::set<ServerNode> presence;
    for (auto it = hosts.Begin(); it != hosts.End(); ++it) {
        auto &host = *it;
        if (!host.IsObject()) {
            LOG(ERROR) << "host member in nacos response is not an object";
            continue;
        }

        auto it_ip = host.FindMember("ip");
        if (it_ip == host.MemberEnd() || !it_ip->value.IsString()) {
            LOG(ERROR) << "host in nacos response has not ip";
            continue;
        }
        auto &ip = it_ip->value;

        auto it_port = host.FindMember("port");
        if (it_port == host.MemberEnd() || !it_port->value.IsInt()) {
            LOG(ERROR) << "host in nacos response has not port";
            continue;
        }
        auto &port = it_port->value;

        auto it_enabled = host.FindMember("enabled");
        if (it_enabled == host.MemberEnd() || !(it_enabled->value.IsBool()) ||
            !(it_enabled->value.GetBool())) {
            LOG(INFO) << "nacos " << ip.GetString() << ":" << port.GetInt()
                      << " is not enabled";
            continue;
        }

        auto it_healthy = host.FindMember("healthy");
        if (it_healthy == host.MemberEnd() || !(it_healthy->value.IsBool()) ||
            !(it_healthy->value.GetBool())) {
            LOG(INFO) << "nacos " << ip.GetString() << ":" << port.GetInt()
                      << " is not healthy";
            continue;
        }

        butil::EndPoint end_point;
        if (str2endpoint(ip.GetString(), port.GetUint(), &end_point) != 0) {
            LOG(ERROR) << "ncos service with illegal address or port: "
                       << ip.GetString() << ":" << port.GetUint();
            continue;
        }

        ServerNode node(end_point);
        auto it_weight = host.FindMember("weight");
        if (it_weight != host.MemberEnd() && it_weight->value.IsNumber()) {
            node.tag =
                std::to_string(static_cast<long>(it_weight->value.GetDouble()));
        }

        presence.insert(node);
    }

    nodes->reserve(presence.size());
    nodes->assign(presence.begin(), presence.end());

    if (nodes->empty() && hosts.Size() != 0) {
        LOG(ERROR) << "All service about " << service_name
                   << " from nacos is invalid, refuse to update servers";
        return -1;
    }

    RPC_VLOG << "Got " << nodes->size()
             << (nodes->size() > 1 ? " servers" : " server") << " from "
             << service_name;

    auto it_cache = doc.FindMember("cacheMillis");
    if (it_cache != doc.MemberEnd() && it_cache->value.IsInt64()) {
        _cache_ms = it_cache->value.GetInt64();
    }

    return 0;
}