std::vector<std::string> toArgsVector(int argc, const char* const* argv) {

  std::vector<std::string> args;

  args.reserve(argc);

  for (int i = 0; i < argc; ++i) {

    args.emplace_back(argv[i]);

  }

  return args;

}

    : OptionsImpl(toArgsVector(argc, argv), hot_restart_version_cb, default_log_level) {}

                         spdlog::level::level_enum default_log_level) {

  std::string log_levels_string = fmt::format("Log levels: {}", allowedLogLevels());

  log_levels_string +=

      fmt::format("\nDefault is [{}]", spdlog::level::level_string_views[default_log_level]);

  const std::string component_log_level_string =

      "Comma-separated list of component log levels. For example upstream:debug,config:trace";

  const std::string log_format_string =

      fmt::format("Log message format in spdlog syntax "

                  "(see https://github.com/gabime/spdlog/wiki/3.-Custom-formatting)"

                  "\nDefault is \"{}\"",

                  Logger::Logger::DEFAULT_LOG_FORMAT);

  TCLAP::CmdLine cmd("envoy", ' ', VersionInfo::version());

  TCLAP::ValueArg<uint32_t> base_id(

      "", "base-id", "Base ID so that multiple envoys can run on the same host if needed", false, 0,

      "uint32_t", cmd);

  TCLAP::SwitchArg use_dynamic_base_id(

      "", "use-dynamic-base-id",

      "The server chooses a base ID dynamically. Supersedes a static base ID. May not be used "

      "when the restart epoch is non-zero.",

      cmd, false);

  TCLAP::SwitchArg skip_hot_restart_on_no_parent(

      "", "skip-hot-restart-on-no-parent",

      "When hot restarting with epoch>0, the default behavior is for the child to crash if the"

      " connection to the parent cannot be established. Set this to true to instead continue with"

      " a regular startup, while retaining the new epoch value.",

      cmd, false);

  TCLAP::SwitchArg skip_hot_restart_parent_stats(

      "", "skip-hot-restart-parent-stats",

      "When hot restarting, by default the child instance copies stats from the parent"

      " instance periodically during the draining period. This can potentially be an"

      " expensive operation; set this to true to reset all stats in child process.",

      cmd, false);

  TCLAP::ValueArg<std::string> base_id_path(

      "", "base-id-path", "Path to which the base ID is written", false, "", "string", cmd);

  TCLAP::ValueArg<uint32_t> concurrency("", "concurrency", "# of worker threads to run", false,

                                        std::thread::hardware_concurrency(), "uint32_t", cmd);

  TCLAP::ValueArg<std::string> config_path("c", "config-path", "Path to configuration file", false,

                                           "", "string", cmd);

  TCLAP::ValueArg<std::string> config_yaml(

      "", "config-yaml", "Inline YAML configuration, merges with the contents of --config-path",

      false, "", "string", cmd);

  TCLAP::SwitchArg allow_unknown_fields("", "allow-unknown-fields",

                                        "Allow unknown fields in static configuration (DEPRECATED)",

                                        cmd, false);

  TCLAP::SwitchArg allow_unknown_static_fields("", "allow-unknown-static-fields",

                                               "Allow unknown fields in static configuration", cmd,

                                               false);

  TCLAP::SwitchArg reject_unknown_dynamic_fields("", "reject-unknown-dynamic-fields",

                                                 "Reject unknown fields in dynamic configuration",

                                                 cmd, false);

  TCLAP::SwitchArg ignore_unknown_dynamic_fields("", "ignore-unknown-dynamic-fields",

                                                 "Ignore unknown fields in dynamic configuration",

                                                 cmd, false);

  TCLAP::SwitchArg skip_deprecated_logs(

      "", "skip-deprecated-logs",

      "Skips the logging of deprecated field warnings during Protobuf message validation", cmd,

      false);

  TCLAP::ValueArg<std::string> admin_address_path("", "admin-address-path", "Admin address path",

                                                  false, "", "string", cmd);

  TCLAP::ValueArg<std::string> local_address_ip_version("", "local-address-ip-version",

                                                        "The local "

                                                        "IP address version (v4 or v6).",

                                                        false, "v4", "string", cmd);

  TCLAP::ValueArg<std::string> log_level(

      "l", "log-level", log_levels_string, false,

      spdlog::level::level_string_views[default_log_level].data(), "string", cmd);

  TCLAP::ValueArg<std::string> component_log_level(

      "", "component-log-level", component_log_level_string, false, "", "string", cmd);

  TCLAP::ValueArg<std::string> log_format("", "log-format", log_format_string, false,

                                          Logger::Logger::DEFAULT_LOG_FORMAT, "string", cmd);

  TCLAP::SwitchArg log_format_escaped("", "log-format-escaped",

                                      "Escape c-style escape sequences in the application logs",

                                      cmd, false);

  TCLAP::SwitchArg enable_fine_grain_logging(

      "", "enable-fine-grain-logging",

      "Logger mode: enable file level log control (Fine-Grain Logger) or not", cmd, false);

  TCLAP::ValueArg<std::string> log_path("", "log-path", "Path to logfile", false, "", "string",

                                        cmd);

  TCLAP::ValueArg<uint32_t> restart_epoch("", "restart-epoch", "Hot restart epoch #", false, 0,

                                          "uint32_t", cmd);

  TCLAP::SwitchArg hot_restart_version_option("", "hot-restart-version",

                                              "Hot restart compatibility version", cmd);

  TCLAP::ValueArg<std::string> service_cluster("", "service-cluster", "Cluster name", false, "",

                                               "string", cmd);

  TCLAP::ValueArg<std::string> service_node("", "service-node", "Node name", false, "", "string",

                                            cmd);

  TCLAP::ValueArg<std::string> service_zone("", "service-zone", "Zone name", false, "", "string",

                                            cmd);

  TCLAP::ValueArg<uint32_t> file_flush_interval_msec("", "file-flush-interval-msec",

                                                     "Interval for log flushing in msec", false,

                                                     10000, "uint32_t", cmd);

  TCLAP::ValueArg<uint32_t> file_flush_min_size_kb("", "file-flush-min-size-kb",

                                                   "Minimum size in KB for log flushing", false, 64,

                                                   "uint32_t", cmd);

  TCLAP::ValueArg<uint32_t> drain_time_s("", "drain-time-s",

                                         "Hot restart and LDS removal drain time in seconds", false,

                                         600, "uint32_t", cmd);

  TCLAP::ValueArg<std::string> drain_strategy(

      "", "drain-strategy",

      "Hot restart drain sequence behaviour, one of 'gradual' (default) or 'immediate'.", false,

      "gradual", "string", cmd);

  TCLAP::ValueArg<uint32_t> parent_shutdown_time_s("", "parent-shutdown-time-s",

                                                   "Hot restart parent shutdown time in seconds",

                                                   false, 900, "uint32_t", cmd);

  TCLAP::ValueArg<std::string> mode("", "mode",

                                    "One of 'serve' (default; validate configs and then serve "

                                    "traffic normally) or 'validate' (validate configs and exit).",

                                    false, "serve", "string", cmd);

  TCLAP::SwitchArg disable_hot_restart("", "disable-hot-restart",

                                       "Disable hot restart functionality", cmd, false);

  TCLAP::SwitchArg enable_mutex_tracing(

      "", "enable-mutex-tracing", "Enable mutex contention tracing functionality", cmd, false);

  TCLAP::SwitchArg cpuset_threads(

      "", "cpuset-threads", "Get the default # of worker threads from cpuset size", cmd, false);

  TCLAP::ValueArg<std::string> disable_extensions("", "disable-extensions",

                                                  "Comma-separated list of extensions to disable",

                                                  false, "", "string", cmd);

  TCLAP::ValueArg<std::string> socket_path("", "socket-path", "Path to hot restart socket file",

                                           false, "@envoy_domain_socket", "string", cmd);

  TCLAP::ValueArg<std::string> socket_mode("", "socket-mode", "Socket file permission", false,

                                           "600", "string", cmd);

  TCLAP::SwitchArg enable_core_dump("", "enable-core-dump", "Enable core dumps", cmd, false);

  TCLAP::MultiArg<std::string> stats_tag(

      "", "stats-tag",

      "This flag provides a universal tag for all stats generated by Envoy. The format is "

      "``tag:value``. Only alphanumeric values are allowed for tag names. For tag values all "

      "characters are permitted except for '.' (dot). This flag can be repeated multiple times to "

      "set multiple universal tags. Multiple values for the same tag name are not allowed.",

      false, "string", cmd);

  cmd.setExceptionHandling(false);

  std::function failure_function = [&](TCLAP::ArgException& e) {

    TRY_ASSERT_MAIN_THREAD { cmd.getOutput()->failure(cmd, e); }

    END_TRY

    CATCH(const TCLAP::ExitException&, {

      throw MalformedArgvException(e.what());

    });

  TRY_ASSERT_MAIN_THREAD {

    cmd.parse(args);

    count_ = cmd.getArgList().size();

  }

  END_TRY

  MULTI_CATCH(

      TCLAP::ArgException & e, { failure_function(e); },

      { throw NoServingException("NoServingException"); });

  hot_restart_disabled_ = disable_hot_restart.getValue();

  mutex_tracing_enabled_ = enable_mutex_tracing.getValue();

  core_dump_enabled_ = enable_core_dump.getValue();

  cpuset_threads_ = cpuset_threads.getValue();

  if (log_level.isSet()) {

    auto status_or_error = parseAndValidateLogLevel(log_level.getValue());

    if (!status_or_error.status().ok()) {

      logError(std::string(status_or_error.status().message()));

    }

    log_level_ = status_or_error.value();

  } else {

    log_level_ = default_log_level;

  }

  log_format_ = log_format.getValue();

  log_format_set_ = log_format.isSet();

  log_format_escaped_ = log_format_escaped.getValue();

  enable_fine_grain_logging_ = enable_fine_grain_logging.getValue();

  if (enable_fine_grain_logging_ && !component_log_level.getValue().empty()) {

    throw MalformedArgvException(

        "error: --component-log-level will not work with --enable-fine-grain-logging");

  }

  parseComponentLogLevels(component_log_level.getValue());

  if (mode.getValue() == "serve") {

    mode_ = Server::Mode::Serve;

  } else if (mode.getValue() == "validate") {

    mode_ = Server::Mode::Validate;

  } else if (mode.getValue() == "init_only") {

    mode_ = Server::Mode::InitOnly;

  } else {

    const std::string message = fmt::format("error: unknown mode '{}'", mode.getValue());

    throw MalformedArgvException(message);

  }

  if (local_address_ip_version.getValue() == "v4") {

    local_address_ip_version_ = Network::Address::IpVersion::v4;

  } else if (local_address_ip_version.getValue() == "v6") {

    local_address_ip_version_ = Network::Address::IpVersion::v6;

  } else {

    const std::string message =

        fmt::format("error: unknown IP address version '{}'", local_address_ip_version.getValue());

    throw MalformedArgvException(message);

  }

  base_id_ = base_id.getValue();

  use_dynamic_base_id_ = use_dynamic_base_id.getValue();

  skip_hot_restart_on_no_parent_ = skip_hot_restart_on_no_parent.getValue();

  skip_hot_restart_parent_stats_ = skip_hot_restart_parent_stats.getValue();

  base_id_path_ = base_id_path.getValue();

  restart_epoch_ = restart_epoch.getValue();

  if (use_dynamic_base_id_ && restart_epoch_ > 0) {

    const std::string message = fmt::format(

        "error: cannot use --restart-epoch={} with --use-dynamic-base-id", restart_epoch_);

    throw MalformedArgvException(message);

  }

  if (!concurrency.isSet() && cpuset_threads_) {

    concurrency_ = OptionsImplPlatform::getCpuCount();

  } else {

    if (concurrency.isSet() && cpuset_threads_ && cpuset_threads.isSet()) {

      ENVOY_LOG(warn, "Both --concurrency and --cpuset-threads options are set; not applying "

                      "--cpuset-threads.");

    }

    concurrency_ = std::max(1U, concurrency.getValue());

  }

  config_path_ = config_path.getValue();

  config_yaml_ = config_yaml.getValue();

  if (allow_unknown_fields.getValue()) {

    if (!skip_deprecated_logs.getValue()) {

      ENVOY_LOG(warn,

                "--allow-unknown-fields is deprecated, use --allow-unknown-static-fields instead.");

    }

  }

  allow_unknown_static_fields_ =

      allow_unknown_static_fields.getValue() || allow_unknown_fields.getValue();

  reject_unknown_dynamic_fields_ = reject_unknown_dynamic_fields.getValue();

  ignore_unknown_dynamic_fields_ = ignore_unknown_dynamic_fields.getValue();

  skip_deprecated_logs_ = skip_deprecated_logs.getValue();

  admin_address_path_ = admin_address_path.getValue();

  log_path_ = log_path.getValue();

  service_cluster_ = service_cluster.getValue();

  service_node_ = service_node.getValue();

  service_zone_ = service_zone.getValue();

  file_flush_interval_msec_ = std::chrono::milliseconds(file_flush_interval_msec.getValue());

  file_flush_min_size_kb_ = file_flush_min_size_kb.getValue();

  drain_time_ = std::chrono::seconds(drain_time_s.getValue());

  parent_shutdown_time_ = std::chrono::seconds(parent_shutdown_time_s.getValue());

  socket_path_ = socket_path.getValue();

  if (socket_path_.at(0) == '@') {

    socket_mode_ = 0;

  } else {

    uint64_t socket_mode_helper;

    if (!StringUtil::atoull(socket_mode.getValue().c_str(), socket_mode_helper, 8)) {

      throw MalformedArgvException(

          fmt::format("error: invalid socket-mode '{}'", socket_mode.getValue()));

    }

    socket_mode_ = socket_mode_helper;

  }

  if (drain_strategy.getValue() == "immediate") {

  } else if (drain_strategy.getValue() == "gradual") {

    drain_strategy_ = Server::DrainStrategy::Gradual;

  } else {

  if (hot_restart_version_option.getValue()) {

    std::cerr << hot_restart_version_cb(!hot_restart_disabled_);

    throw NoServingException("NoServingException");

  }

  if (!disable_extensions.getValue().empty()) {

  if (!stats_tag.getValue().empty()) {

    for (const auto& cli_tag_pair : stats_tag.getValue()) {

      std::vector<absl::string_view> cli_tag_pair_tokens =

          absl::StrSplit(cli_tag_pair, absl::MaxSplits(':', 1));

      if (cli_tag_pair_tokens.size() != 2) {

        throw MalformedArgvException(

            fmt::format("error: misformatted stats-tag '{}'", cli_tag_pair));

      }

      auto name = cli_tag_pair_tokens[0];

      if (!Stats::TagUtility::isTagNameValid(name)) {

        throw MalformedArgvException(

            fmt::format("error: misformatted stats-tag '{}' contains invalid char in '{}'",

                        cli_tag_pair, name));

      }

      auto value = cli_tag_pair_tokens[1];

      if (!Stats::TagUtility::isTagValueValid(value)) {

        throw MalformedArgvException(

            fmt::format("error: misformatted stats-tag '{}' contains invalid char in '{}'",

                        cli_tag_pair, value));

      }

      stats_tags_.emplace_back(Stats::Tag{std::string(name), std::string(value)});

    }

  }

}

std::string OptionsImpl::allowedLogLevels() {

  std::string allowed_log_levels;

  for (auto level_string_view : spdlog::level::level_string_views) {

    if (level_string_view == spdlog::level::to_string_view(spdlog::level::warn)) {

      allowed_log_levels += fmt::format("[{}|warn]", level_string_view);

    } else {

      allowed_log_levels += fmt::format("[{}]", level_string_view);

    }

  }

  return allowed_log_levels;

}

void OptionsImpl::parseComponentLogLevels(const std::string& component_log_levels) {

  if (component_log_levels.empty()) {

    return;

  }

  component_log_level_str_ = component_log_levels;

  std::vector<std::string> log_levels = absl::StrSplit(component_log_levels, ',');

  for (auto& level : log_levels) {

    std::vector<std::string> log_name_level = absl::StrSplit(level, ':');

    if (log_name_level.size() != 2) {

      logError(fmt::format("error: component log level not correctly specified '{}'", level));

    }

    std::string log_name = log_name_level[0];

    auto status_or_error = parseAndValidateLogLevel(log_name_level[1]);

    if (!status_or_error.status().ok()) {

      logError(std::string(status_or_error.status().message()));

    }

    spdlog::level::level_enum log_level = status_or_error.value();

    Logger::Logger* logger_to_change = Logger::Registry::logger(log_name);

    if (!logger_to_change) {

      logError(fmt::format("error: invalid component specified '{}'", log_name));

    }

    component_log_levels_.push_back(std::make_pair(log_name, log_level));

  }

}

void OptionsImpl::logError(const std::string& error) { throw MalformedArgvException(error); }

Server::CommandLineOptionsPtr OptionsImpl::toCommandLineOptions() const {

  Server::CommandLineOptionsPtr command_line_options =

      std::make_unique<envoy::admin::v3::CommandLineOptions>();

  command_line_options->set_base_id(baseId());

  command_line_options->set_use_dynamic_base_id(useDynamicBaseId());

  command_line_options->set_skip_hot_restart_on_no_parent(skipHotRestartOnNoParent());

  command_line_options->set_skip_hot_restart_parent_stats(skipHotRestartParentStats());

  command_line_options->set_base_id_path(baseIdPath());

  command_line_options->set_concurrency(concurrency());

  command_line_options->set_config_path(configPath());

  command_line_options->set_config_yaml(configYaml());

  command_line_options->set_allow_unknown_static_fields(allow_unknown_static_fields_);

  command_line_options->set_reject_unknown_dynamic_fields(reject_unknown_dynamic_fields_);

  command_line_options->set_ignore_unknown_dynamic_fields(ignore_unknown_dynamic_fields_);

  command_line_options->set_skip_deprecated_logs(skip_deprecated_logs_);

  command_line_options->set_admin_address_path(adminAddressPath());

  command_line_options->set_component_log_level(component_log_level_str_);

  command_line_options->set_log_level(spdlog::level::to_string_view(logLevel()).data(),

                                      spdlog::level::to_string_view(logLevel()).size());

  command_line_options->set_log_format(logFormat());

  command_line_options->set_log_format_escaped(logFormatEscaped());

  command_line_options->set_enable_fine_grain_logging(enableFineGrainLogging());

  command_line_options->set_log_path(logPath());

  command_line_options->set_service_cluster(serviceClusterName());

  command_line_options->set_service_node(serviceNodeName());

  command_line_options->set_service_zone(serviceZone());

  if (mode() == Server::Mode::Serve) {

    command_line_options->set_mode(envoy::admin::v3::CommandLineOptions::Serve);

  } else if (mode() == Server::Mode::Validate) {

    command_line_options->set_mode(envoy::admin::v3::CommandLineOptions::Validate);

  } else {

  if (localAddressIpVersion() == Network::Address::IpVersion::v4) {

    command_line_options->set_local_address_ip_version(envoy::admin::v3::CommandLineOptions::v4);

  } else {

    command_line_options->set_local_address_ip_version(envoy::admin::v3::CommandLineOptions::v6);

  }

  command_line_options->mutable_file_flush_interval()->MergeFrom(

      Protobuf::util::TimeUtil::MillisecondsToDuration(fileFlushIntervalMsec().count()));

  command_line_options->mutable_drain_time()->MergeFrom(

      Protobuf::util::TimeUtil::SecondsToDuration(drainTime().count()));

  command_line_options->set_drain_strategy(drainStrategy() == Server::DrainStrategy::Immediate

                                               ? envoy::admin::v3::CommandLineOptions::Immediate

                                               : envoy::admin::v3::CommandLineOptions::Gradual);

  command_line_options->mutable_parent_shutdown_time()->MergeFrom(

      Protobuf::util::TimeUtil::SecondsToDuration(parentShutdownTime().count()));

  command_line_options->set_disable_hot_restart(hotRestartDisabled());

  command_line_options->set_enable_mutex_tracing(mutexTracingEnabled());

  command_line_options->set_cpuset_threads(cpusetThreadsEnabled());

  command_line_options->set_restart_epoch(restartEpoch());

  for (const auto& e : disabledExtensions()) {

  command_line_options->set_socket_path(socketPath());

  command_line_options->set_socket_mode(socketMode());

  for (const auto& tag : statsTags()) {

    command_line_options->add_stats_tag(fmt::format("{}:{}", tag.name_, tag.value_));

  }

  return command_line_options;

}

                         const std::string& service_zone, spdlog::level::level_enum log_level) {

  setLogLevel(log_level);

  setServiceClusterName(service_cluster);

  setServiceNodeName(service_node);

  setServiceZone(service_zone);

}