bool FailoverService::failover_writer()

in src/failover/failover_service.cc [310:344]

• 32 lines of code
• 5 McCabe index (conditional complexity)

bool FailoverService::failover_writer(SQLHDBC hdbc) {
    topology_monitor_->ForceRefresh(true, failover_timeout_);

    // Try connecting to a writer
    std::vector<HostInfo> hosts = topology_map_->Get(cluster_id_);
    std::unordered_map<std::string, std::string> properties;
    RoundRobinHostSelector::SetRoundRobinWeight(hosts, properties);
    HostInfo host;    
    try {
        host = host_selector_->GetHost(hosts, true, properties);
    } catch (const std::exception& e) {
        LOG(INFO) << "[Failover Service] no hosts in topology for: " << cluster_id_;
        return false;
    }
    std::string host_string = host.GetHost();
    LOG(INFO) << "[Failover Service] writer failover connection to a new writer: " << host_string;

    bool is_connected = connect_to_host(hdbc, host_string);
    if (!is_connected) {
        LOG(INFO) << "[Failover Service] writer failover unable to connect to any instance for: " << cluster_id_;
        return false;
    }
    if (odbc_helper_->CheckConnection(hdbc)) {
        if (!is_connected_to_reader(hdbc)) {
            LOG(INFO) << "[Failover Service] writer failover connected to a new writer for: " << host_string;
            curr_host_ = host;
            return true;
        }
        LOG(ERROR) << "The new writer was identified to be " << host_string << ", but querying the instance for its role returned a reader.";
        return false;
    }
    LOG(INFO) << "[Failover Service] writer failover unable to connect to any instance for: " << cluster_id_;
    SQLDisconnect(hdbc);
    return false;
}