#include "source/server/server.h"

#include <csignal>

#include <cstdint>

#include <ctime>

#include <functional>

#include <memory>

#include <string>

#include "envoy/admin/v3/config_dump.pb.h"

#include "envoy/common/exception.h"

#include "envoy/common/time.h"

#include "envoy/config/bootstrap/v3/bootstrap.pb.h"

#include "envoy/config/bootstrap/v3/bootstrap.pb.validate.h"

#include "envoy/event/dispatcher.h"

#include "envoy/event/signal.h"

#include "envoy/event/timer.h"

#include "envoy/network/dns.h"

#include "envoy/registry/registry.h"

#include "envoy/server/bootstrap_extension_config.h"

#include "envoy/server/instance.h"

#include "envoy/server/options.h"

#include "envoy/stats/histogram.h"

#include "envoy/stats/stats.h"

#include "envoy/upstream/cluster_manager.h"

#include "source/common/api/api_impl.h"

#include "source/common/api/os_sys_calls_impl.h"

#include "source/common/common/enum_to_int.h"

#include "source/common/common/mutex_tracer_impl.h"

#include "source/common/common/utility.h"

#include "source/common/config/utility.h"

#include "source/common/config/well_known_names.h"

#include "source/common/config/xds_resource.h"

#include "source/common/http/codes.h"

#include "source/common/http/headers.h"

#include "source/common/local_info/local_info_impl.h"

#include "source/common/memory/stats.h"

#include "source/common/network/address_impl.h"

#include "source/common/network/dns_resolver/dns_factory_util.h"

#include "source/common/network/socket_interface.h"

#include "source/common/network/socket_interface_impl.h"

#include "source/common/network/tcp_listener_impl.h"

#include "source/common/protobuf/utility.h"

#include "source/common/router/rds_impl.h"

#include "source/common/runtime/runtime_impl.h"

#include "source/common/signal/fatal_error_handler.h"

#include "source/common/singleton/manager_impl.h"

#include "source/common/stats/thread_local_store.h"

#include "source/common/stats/timespan_impl.h"

#include "source/common/upstream/cluster_manager_impl.h"

#include "source/common/version/version.h"

#include "source/server/configuration_impl.h"

#include "source/server/guarddog_impl.h"

#include "source/server/listener_hooks.h"

#include "source/server/listener_manager_factory.h"

#include "source/server/regex_engine.h"

#include "source/server/ssl_context_manager.h"

#include "source/server/utils.h"

namespace Envoy {

namespace Server {

namespace {

std::unique_ptr<ConnectionHandler> getHandler(Event::Dispatcher& dispatcher) {

  auto* factory = Config::Utility::getFactoryByName<ConnectionHandlerFactory>(

      "envoy.connection_handler.default");

  if (factory) {

    return factory->createConnectionHandler(dispatcher, absl::nullopt);

  }

  ENVOY_LOG_MISC(debug, "Unable to find envoy.connection_handler.default factory");

  return nullptr;

}

} // namespace

InstanceBase::InstanceBase(Init::Manager& init_manager, const Options& options,

                           Event::TimeSystem& time_system, ListenerHooks& hooks,

                           HotRestart& restarter, Stats::StoreRoot& store,

                           Thread::BasicLockable& access_log_lock,

                           Random::RandomGeneratorPtr&& random_generator,

                           ThreadLocal::Instance& tls, Thread::ThreadFactory& thread_factory,

                           Filesystem::Instance& file_system,

                           std::unique_ptr<ProcessContext> process_context,

                           Buffer::WatermarkFactorySharedPtr watermark_factory)

    : init_manager_(init_manager), live_(false), options_(options),

      validation_context_(options_.allowUnknownStaticFields(),

                          !options.rejectUnknownDynamicFields(),

                          options.ignoreUnknownDynamicFields()),

      time_source_(time_system), restarter_(restarter), start_time_(time(nullptr)),

      original_start_time_(start_time_), stats_store_(store), thread_local_(tls),

      random_generator_(std::move(random_generator)),

      api_(new Api::Impl(

          thread_factory, store, time_system, file_system, *random_generator_, bootstrap_,

          process_context ? ProcessContextOptRef(std::ref(*process_context)) : absl::nullopt,

          watermark_factory)),

      dispatcher_(api_->allocateDispatcher("main_thread")),

      access_log_manager_(options.fileFlushIntervalMsec(), *api_, *dispatcher_, access_log_lock,

                          store),

      singleton_manager_(new Singleton::ManagerImpl(api_->threadFactory())),

      handler_(getHandler(*dispatcher_)), worker_factory_(thread_local_, *api_, hooks),

      mutex_tracer_(options.mutexTracingEnabled() ? &Envoy::MutexTracerImpl::getOrCreateTracer()

                                                  : nullptr),

      grpc_context_(store.symbolTable()), http_context_(store.symbolTable()),

      router_context_(store.symbolTable()), process_context_(std::move(process_context)),

      hooks_(hooks), quic_stat_names_(store.symbolTable()), server_contexts_(*this),

      enable_reuse_port_default_(true), stats_flush_in_progress_(false) {}

InstanceBase::~InstanceBase() {

  terminate();

  // Stop logging to file before all the AccessLogManager and its dependencies are

  // destructed to avoid crashing at shutdown.

  file_logger_.reset();

  // Destruct the ListenerManager explicitly, before InstanceBase's local init_manager_ is

  // destructed.

  //

  // The ListenerManager's DestinationPortsMap contains FilterChainSharedPtrs. There is a rare race

  // condition where one of these FilterChains contains an HttpConnectionManager, which contains an

  // RdsRouteConfigProvider, which contains an RdsRouteConfigSubscriptionSharedPtr. Since

  // RdsRouteConfigSubscription is an Init::Target, ~RdsRouteConfigSubscription triggers a callback

  // set at initialization, which goes to unregister it from the top-level InitManager, which has

  // already been destructed (use-after-free) causing a segfault.

  ENVOY_LOG(debug, "destroying listener manager");

  listener_manager_.reset();

  ENVOY_LOG(debug, "destroyed listener manager");

  dispatcher_->shutdown();

#ifdef ENVOY_PERFETTO

  if (tracing_session_ != nullptr) {

    // Flush the trace data.

    perfetto::TrackEvent::Flush();

    // Disable tracing and block until tracing has stopped.

    tracing_session_->StopBlocking();

    close(tracing_fd_);

  }

#endif

}

Upstream::ClusterManager& InstanceBase::clusterManager() {

  ASSERT(config_.clusterManager() != nullptr);

  return *config_.clusterManager();

}

const Upstream::ClusterManager& InstanceBase::clusterManager() const {

  ASSERT(config_.clusterManager() != nullptr);

  return *config_.clusterManager();

}

void InstanceBase::drainListeners(OptRef<const Network::ExtraShutdownListenerOptions> options) {

  ENVOY_LOG(info, "closing and draining listeners");

  listener_manager_->stopListeners(ListenerManager::StopListenersType::All,

                                   options.has_value() ? *options

                                                       : Network::ExtraShutdownListenerOptions{});

  drain_manager_->startDrainSequence([] {});

}

void InstanceBase::failHealthcheck(bool fail) {

  live_.store(!fail);

  server_stats_->live_.set(live_.load());

}

MetricSnapshotImpl::MetricSnapshotImpl(Stats::Store& store,

                                       Upstream::ClusterManager& cluster_manager,

                                       TimeSource& time_source) {

  store.forEachSinkedCounter(

      [this](std::size_t size) {

        snapped_counters_.reserve(size);

        counters_.reserve(size);

      },

      [this](Stats::Counter& counter) {

        snapped_counters_.push_back(Stats::CounterSharedPtr(&counter));

        counters_.push_back({counter.latch(), counter});

      });

  store.forEachSinkedGauge(

      [this](std::size_t size) {

        snapped_gauges_.reserve(size);

        gauges_.reserve(size);

      },

      [this](Stats::Gauge& gauge) {

        snapped_gauges_.push_back(Stats::GaugeSharedPtr(&gauge));

        gauges_.push_back(gauge);

      });

  store.forEachSinkedHistogram(

      [this](std::size_t size) {

        snapped_histograms_.reserve(size);

        histograms_.reserve(size);

      },

      [this](Stats::ParentHistogram& histogram) {

        snapped_histograms_.push_back(Stats::ParentHistogramSharedPtr(&histogram));

        histograms_.push_back(histogram);

      });

  store.forEachSinkedTextReadout(

      [this](std::size_t size) {

        snapped_text_readouts_.reserve(size);

        text_readouts_.reserve(size);

      },

      [this](Stats::TextReadout& text_readout) {

        snapped_text_readouts_.push_back(Stats::TextReadoutSharedPtr(&text_readout));

        text_readouts_.push_back(text_readout);

      });

  Upstream::HostUtility::forEachHostMetric(

      cluster_manager,

      [this](Stats::PrimitiveCounterSnapshot&& metric) {

        host_counters_.emplace_back(std::move(metric));

      },

      [this](Stats::PrimitiveGaugeSnapshot&& metric) {

        host_gauges_.emplace_back(std::move(metric));

      });

  snapshot_time_ = time_source.systemTime();

}

void InstanceUtil::flushMetricsToSinks(const std::list<Stats::SinkPtr>& sinks, Stats::Store& store,

                                       Upstream::ClusterManager& cm, TimeSource& time_source) {

  // Create a snapshot and flush to all sinks.

  // NOTE: Even if there are no sinks, creating the snapshot has the important property that it

  //       latches all counters on a periodic basis. The hot restart code assumes this is being

  //       done so this should not be removed.

  MetricSnapshotImpl snapshot(store, cm, time_source);

  for (const auto& sink : sinks) {

    sink->flush(snapshot);

  }

}

void InstanceBase::flushStats() {

  if (stats_flush_in_progress_) {

    ENVOY_LOG(debug, "skipping stats flush as flush is already in progress");

    server_stats_->dropped_stat_flushes_.inc();

    return;

  }

  stats_flush_in_progress_ = true;

  ENVOY_LOG(debug, "flushing stats");

  // If Envoy is not fully initialized, workers will not be started and mergeHistograms

  // completion callback is not called immediately. As a result of this server stats will

  // not be updated and flushed to stat sinks. So skip mergeHistograms call if workers are

  // not started yet.

  if (initManager().state() == Init::Manager::State::Initialized) {

    // A shutdown initiated before this callback may prevent this from being called as per

    // the semantics documented in ThreadLocal's runOnAllThreads method.

    stats_store_.mergeHistograms([this]() -> void { flushStatsInternal(); });

  } else {

    ENVOY_LOG(debug, "Envoy is not fully initialized, skipping histogram merge and flushing stats");

    flushStatsInternal();

  }

}

void InstanceBase::updateServerStats() {

  // mergeParentStatsIfAny() does nothing and returns a struct of 0s if there is no parent.

  HotRestart::ServerStatsFromParent parent_stats = restarter_.mergeParentStatsIfAny(stats_store_);

  server_stats_->uptime_.set(time(nullptr) - original_start_time_);

  server_stats_->memory_allocated_.set(Memory::Stats::totalCurrentlyAllocated() +

                                       parent_stats.parent_memory_allocated_);

  server_stats_->memory_heap_size_.set(Memory::Stats::totalCurrentlyReserved());

  server_stats_->memory_physical_size_.set(Memory::Stats::totalPhysicalBytes());

  server_stats_->parent_connections_.set(parent_stats.parent_connections_);

  server_stats_->total_connections_.set(listener_manager_->numConnections() +

                                        parent_stats.parent_connections_);

  server_stats_->days_until_first_cert_expiring_.set(

      sslContextManager().daysUntilFirstCertExpires().value_or(0));

  auto secs_until_ocsp_response_expires =

      sslContextManager().secondsUntilFirstOcspResponseExpires();

  if (secs_until_ocsp_response_expires) {

    server_stats_->seconds_until_first_ocsp_response_expiring_.set(

        secs_until_ocsp_response_expires.value());

  }

  server_stats_->state_.set(

      enumToInt(Utility::serverState(initManager().state(), healthCheckFailed())));

  server_stats_->stats_recent_lookups_.set(

      stats_store_.symbolTable().getRecentLookups([](absl::string_view, uint64_t) {}));

}

void InstanceBase::flushStatsInternal() {

  updateServerStats();

  auto& stats_config = config_.statsConfig();

  InstanceUtil::flushMetricsToSinks(stats_config.sinks(), stats_store_, clusterManager(),

                                    timeSource());

  // TODO(ramaraochavali): consider adding different flush interval for histograms.

  if (stat_flush_timer_ != nullptr) {

    stat_flush_timer_->enableTimer(stats_config.flushInterval());

  }

  stats_flush_in_progress_ = false;

}

bool InstanceBase::healthCheckFailed() { return !live_.load(); }

ProcessContextOptRef InstanceBase::processContext() {

  if (process_context_ == nullptr) {

    return absl::nullopt;

  }

  return *process_context_;

}

namespace {

bool canBeRegisteredAsInlineHeader(const Http::LowerCaseString& header_name) {

  // 'set-cookie' cannot currently be registered as an inline header.

  if (header_name == Http::Headers::get().SetCookie) {

    return false;

  }

  return true;

}

void registerCustomInlineHeadersFromBootstrap(

    const envoy::config::bootstrap::v3::Bootstrap& bootstrap) {

  for (const auto& inline_header : bootstrap.inline_headers()) {

    const Http::LowerCaseString lower_case_name(inline_header.inline_header_name());

    if (!canBeRegisteredAsInlineHeader(lower_case_name)) {

      throwEnvoyExceptionOrPanic(fmt::format("Header {} cannot be registered as an inline header.",

                                             inline_header.inline_header_name()));

    }

    switch (inline_header.inline_header_type()) {

    case envoy::config::bootstrap::v3::CustomInlineHeader::REQUEST_HEADER:

      Http::CustomInlineHeaderRegistry::registerInlineHeader<

          Http::RequestHeaderMap::header_map_type>(lower_case_name);

      break;

    case envoy::config::bootstrap::v3::CustomInlineHeader::REQUEST_TRAILER:

      Http::CustomInlineHeaderRegistry::registerInlineHeader<

          Http::RequestTrailerMap::header_map_type>(lower_case_name);

      break;

    case envoy::config::bootstrap::v3::CustomInlineHeader::RESPONSE_HEADER:

      Http::CustomInlineHeaderRegistry::registerInlineHeader<

          Http::ResponseHeaderMap::header_map_type>(lower_case_name);

      break;

    case envoy::config::bootstrap::v3::CustomInlineHeader::RESPONSE_TRAILER:

      Http::CustomInlineHeaderRegistry::registerInlineHeader<

          Http::ResponseTrailerMap::header_map_type>(lower_case_name);

      break;

    default:

      PANIC("not implemented");

    }

  }

}

} // namespace

void InstanceUtil::loadBootstrapConfig(envoy::config::bootstrap::v3::Bootstrap& bootstrap,

                                       const Options& options,

                                       ProtobufMessage::ValidationVisitor& validation_visitor,

                                       Api::Api& api) {

  const std::string& config_path = options.configPath();

  const std::string& config_yaml = options.configYaml();

  const envoy::config::bootstrap::v3::Bootstrap& config_proto = options.configProto();

  // One of config_path and config_yaml or bootstrap should be specified.

  if (config_path.empty() && config_yaml.empty() && config_proto.ByteSizeLong() == 0) {

    throwEnvoyExceptionOrPanic(

        "At least one of --config-path or --config-yaml or Options::configProto() "

        "should be non-empty");

  }

  if (!config_path.empty()) {

#ifdef ENVOY_ENABLE_YAML

    MessageUtil::loadFromFile(config_path, bootstrap, validation_visitor, api);

#else

    if (!config_path.empty()) {

      throwEnvoyExceptionOrPanic("Cannot load from file with YAML disabled\n");

    }

    UNREFERENCED_PARAMETER(api);

#endif

  }

  if (!config_yaml.empty()) {

#ifdef ENVOY_ENABLE_YAML

    envoy::config::bootstrap::v3::Bootstrap bootstrap_override;

    MessageUtil::loadFromYaml(config_yaml, bootstrap_override, validation_visitor);

    // TODO(snowp): The fact that we do a merge here doesn't seem to be covered under test.

    bootstrap.MergeFrom(bootstrap_override);

#else

    throwEnvoyExceptionOrPanic("Cannot load from YAML with YAML disabled\n");

#endif

  }

  if (config_proto.ByteSizeLong() != 0) {

    bootstrap.MergeFrom(config_proto);

  }

  MessageUtil::validate(bootstrap, validation_visitor);

}

void InstanceBase::initialize(Network::Address::InstanceConstSharedPtr local_address,

                              ComponentFactory& component_factory) {

  std::function set_up_logger = [&] {

    TRY_ASSERT_MAIN_THREAD {

      file_logger_ = std::make_unique<Logger::FileSinkDelegate>(

          options_.logPath(), access_log_manager_, Logger::Registry::getSink());

    }

    END_TRY

    CATCH(const EnvoyException& e, {

      throw EnvoyException(

          fmt::format("Failed to open log-file '{}'. e.what(): {}", options_.logPath(), e.what()));

    });

  };

  TRY_ASSERT_MAIN_THREAD {

    if (!options_.logPath().empty()) {

      set_up_logger();

    }

    restarter_.initialize(*dispatcher_, *this);

    drain_manager_ = component_factory.createDrainManager(*this);

    initializeOrThrow(std::move(local_address), component_factory);

  }

  END_TRY

  MULTI_CATCH(

      const EnvoyException& e,

      {

        ENVOY_LOG(critical, "error initializing config '{} {} {}': {}",

                  options_.configProto().DebugString(), options_.configYaml(),

                  options_.configPath(), e.what());

        terminate();

        throw;

      },

      {

        ENVOY_LOG(critical, "error initializing due to unknown exception");

        terminate();

        throw;

      });

}

void InstanceBase::initializeOrThrow(Network::Address::InstanceConstSharedPtr local_address,

                                     ComponentFactory& component_factory) {

  ENVOY_LOG(info, "initializing epoch {} (base id={}, hot restart version={})",

            options_.restartEpoch(), restarter_.baseId(), restarter_.version());

  ENVOY_LOG(info, "statically linked extensions:");

  for (const auto& ext : Envoy::Registry::FactoryCategoryRegistry::registeredFactories()) {

    ENVOY_LOG(info, "  {}: {}", ext.first, absl::StrJoin(ext.second->registeredNames(), ", "));

  }

  // Handle configuration that needs to take place prior to the main configuration load.

  InstanceUtil::loadBootstrapConfig(bootstrap_, options_,

                                    messageValidationContext().staticValidationVisitor(), *api_);

  bootstrap_config_update_time_ = time_source_.systemTime();

  if (bootstrap_.has_application_log_config()) {

    THROW_IF_NOT_OK(

        Utility::assertExclusiveLogFormatMethod(options_, bootstrap_.application_log_config()));

    THROW_IF_NOT_OK(Utility::maybeSetApplicationLogFormat(bootstrap_.application_log_config()));

  }

#ifdef ENVOY_PERFETTO

  perfetto::TracingInitArgs args;

  // Include in-process events only.

  args.backends = perfetto::kInProcessBackend;

  perfetto::Tracing::Initialize(args);

  perfetto::TrackEvent::Register();

  // Prepare a configuration for a new "Perfetto" tracing session.

  perfetto::TraceConfig cfg;

  // TODO(rojkov): make the tracer configurable with either "Perfetto"'s native

  // message or custom one embedded into Bootstrap.

  cfg.add_buffers()->set_size_kb(1024);

  auto* ds_cfg = cfg.add_data_sources()->mutable_config();

  ds_cfg->set_name("track_event");

  const std::string pftrace_path =

      PROTOBUF_GET_STRING_OR_DEFAULT(bootstrap_, perf_tracing_file_path, "envoy.pftrace");

  // Instantiate a new tracing session.

  tracing_session_ = perfetto::Tracing::NewTrace();

  tracing_fd_ = open(pftrace_path.c_str(), O_RDWR | O_CREAT | O_TRUNC, 0600);

  if (tracing_fd_ == -1) {

    throwEnvoyExceptionOrPanic(

        fmt::format("unable to open tracing file {}: {}", pftrace_path, errorDetails(errno)));

  }

  // Configure the tracing session.

  tracing_session_->Setup(cfg, tracing_fd_);

  // Enable tracing and block until tracing has started.

  tracing_session_->StartBlocking();

#endif

  // Immediate after the bootstrap has been loaded, override the header prefix, if configured to

  // do so. This must be set before any other code block references the HeaderValues ConstSingleton.

  if (!bootstrap_.header_prefix().empty()) {

    // setPrefix has a release assert verifying that setPrefix() is not called after prefix()

    ThreadSafeSingleton<Http::PrefixValue>::get().setPrefix(bootstrap_.header_prefix().c_str());

  }

  // Register Custom O(1) headers from bootstrap.

  registerCustomInlineHeadersFromBootstrap(bootstrap_);

  ENVOY_LOG(info, "HTTP header map info:");

  for (const auto& info : Http::HeaderMapImplUtility::getAllHeaderMapImplInfo()) {

    ENVOY_LOG(info, "  {}: {} bytes: {}", info.name_, info.size_,

              absl::StrJoin(info.registered_headers_, ","));

  }

  // Initialize the regex engine and inject to singleton.

  // Needs to happen before stats store initialization because the stats

  // matcher config can include regexes.

  regex_engine_ = createRegexEngine(

      bootstrap_, messageValidationContext().staticValidationVisitor(), serverFactoryContext());

  // Needs to happen as early as possible in the instantiation to preempt the objects that require

  // stats.

  stats_store_.setTagProducer(Config::Utility::createTagProducer(bootstrap_, options_.statsTags()));

  stats_store_.setStatsMatcher(

      Config::Utility::createStatsMatcher(bootstrap_, stats_store_.symbolTable()));

  stats_store_.setHistogramSettings(Config::Utility::createHistogramSettings(bootstrap_));

  const std::string server_stats_prefix = "server.";

  const std::string server_compilation_settings_stats_prefix = "server.compilation_settings";

  server_stats_ = std::make_unique<ServerStats>(

      ServerStats{ALL_SERVER_STATS(POOL_COUNTER_PREFIX(stats_store_, server_stats_prefix),

                                   POOL_GAUGE_PREFIX(stats_store_, server_stats_prefix),

                                   POOL_HISTOGRAM_PREFIX(stats_store_, server_stats_prefix))});

  server_compilation_settings_stats_ =

      std::make_unique<CompilationSettings::ServerCompilationSettingsStats>(

          CompilationSettings::ServerCompilationSettingsStats{ALL_SERVER_COMPILATION_SETTINGS_STATS(

              POOL_COUNTER_PREFIX(stats_store_, server_compilation_settings_stats_prefix),

              POOL_GAUGE_PREFIX(stats_store_, server_compilation_settings_stats_prefix),

              POOL_HISTOGRAM_PREFIX(stats_store_, server_compilation_settings_stats_prefix))});

  validation_context_.setCounters(server_stats_->static_unknown_fields_,

                                  server_stats_->dynamic_unknown_fields_,

                                  server_stats_->wip_protos_);

  initialization_timer_ = std::make_unique<Stats::HistogramCompletableTimespanImpl>(

      server_stats_->initialization_time_ms_, timeSource());

  server_stats_->concurrency_.set(options_.concurrency());

  server_stats_->hot_restart_epoch_.set(options_.restartEpoch());

  InstanceBase::failHealthcheck(false);

  // Check if bootstrap has server version override set, if yes, we should use that as

  // 'server.version' stat.

  uint64_t version_int;

  if (bootstrap_.stats_server_version_override().value() > 0) {

    version_int = bootstrap_.stats_server_version_override().value();

  } else {

    if (!StringUtil::atoull(VersionInfo::revision().substr(0, 6).c_str(), version_int, 16)) {

      throwEnvoyExceptionOrPanic("compiled GIT SHA is invalid. Invalid build.");

    }

  }

  server_stats_->version_.set(version_int);

  if (VersionInfo::sslFipsCompliant()) {

    server_compilation_settings_stats_->fips_mode_.set(1);

  } else {

    // Set this explicitly so that "used" flag is set so that it can be pushed to stats sinks.

    server_compilation_settings_stats_->fips_mode_.set(0);

  }

  // If user has set user_agent_name in the bootstrap config, use it.

  // Default to "envoy" if unset.

  if (bootstrap_.node().user_agent_name().empty()) {

    bootstrap_.mutable_node()->set_user_agent_name("envoy");

  }

  // If user has set user_agent_build_version in the bootstrap config, use it.

  // Default to the internal server version.

  if (!bootstrap_.node().user_agent_build_version().has_version()) {

    *bootstrap_.mutable_node()->mutable_user_agent_build_version() = VersionInfo::buildVersion();

  }

  for (const auto& ext : Envoy::Registry::FactoryCategoryRegistry::registeredFactories()) {

    auto registered_types = ext.second->registeredTypes();

    for (const auto& name : ext.second->allRegisteredNames()) {

      auto* extension = bootstrap_.mutable_node()->add_extensions();

      extension->set_name(std::string(name));

      extension->set_category(ext.first);

      auto const version = ext.second->getFactoryVersion(name);

      if (version) {

        *extension->mutable_version() = version.value();

      }

      extension->set_disabled(ext.second->isFactoryDisabled(name));

      auto it = registered_types.find(name);

      if (it != registered_types.end()) {

        std::sort(it->second.begin(), it->second.end());

        for (const auto& type_url : it->second) {

          extension->add_type_urls(type_url);

        }

      }

    }

  }

  local_info_ = std::make_unique<LocalInfo::LocalInfoImpl>(

      stats().symbolTable(), bootstrap_.node(), bootstrap_.node_context_params(), local_address,

      options_.serviceZone(), options_.serviceClusterName(), options_.serviceNodeName());

  Configuration::InitialImpl initial_config(bootstrap_);

  // Learn original_start_time_ if our parent is still around to inform us of it.

  const auto parent_admin_shutdown_response = restarter_.sendParentAdminShutdownRequest();

  if (parent_admin_shutdown_response.has_value()) {

    original_start_time_ = parent_admin_shutdown_response.value().original_start_time_;

    // TODO(soulxu): This is added for switching the reuse port default value as true (#17259).

    // It ensures the same default value during the hot restart. This can be removed when

    // everyone switches to the new default value.

    enable_reuse_port_default_ =

        parent_admin_shutdown_response.value().enable_reuse_port_default_ ? true : false;

  }

  OptRef<Server::ConfigTracker> config_tracker;

#ifdef ENVOY_ADMIN_FUNCTIONALITY

  admin_ = std::make_unique<AdminImpl>(initial_config.admin().profilePath(), *this,

                                       initial_config.admin().ignoreGlobalConnLimit());

  config_tracker = admin_->getConfigTracker();

#endif

  secret_manager_ = std::make_unique<Secret::SecretManagerImpl>(config_tracker);

  loadServerFlags(initial_config.flagsPath());

  // Initialize the overload manager early so other modules can register for actions.

  overload_manager_ = std::make_unique<OverloadManagerImpl>(

      *dispatcher_, *stats_store_.rootScope(), thread_local_, bootstrap_.overload_manager(),

      messageValidationContext().staticValidationVisitor(), *api_, options_);

  maybeCreateHeapShrinker();

  for (const auto& bootstrap_extension : bootstrap_.bootstrap_extensions()) {

    auto& factory = Config::Utility::getAndCheckFactory<Configuration::BootstrapExtensionFactory>(

        bootstrap_extension);

    auto config = Config::Utility::translateAnyToFactoryConfig(

        bootstrap_extension.typed_config(), messageValidationContext().staticValidationVisitor(),

        factory);

    bootstrap_extensions_.push_back(

        factory.createBootstrapExtension(*config, serverFactoryContext()));

  }

  // Register the fatal actions.

  {

    FatalAction::FatalActionPtrList safe_actions;

    FatalAction::FatalActionPtrList unsafe_actions;

    for (const auto& action_config : bootstrap_.fatal_actions()) {

      auto& factory =

          Config::Utility::getAndCheckFactory<Server::Configuration::FatalActionFactory>(

              action_config.config());

      auto action = factory.createFatalActionFromProto(action_config, this);

      if (action->isAsyncSignalSafe()) {

        safe_actions.push_back(std::move(action));

      } else {

        unsafe_actions.push_back(std::move(action));

      }

    }

    Envoy::FatalErrorHandler::registerFatalActions(

        std::move(safe_actions), std::move(unsafe_actions), api_->threadFactory());

  }

  if (!bootstrap_.default_socket_interface().empty()) {

    auto& sock_name = bootstrap_.default_socket_interface();

    auto sock = const_cast<Network::SocketInterface*>(Network::socketInterface(sock_name));

    if (sock != nullptr) {

      Network::SocketInterfaceSingleton::clear();

      Network::SocketInterfaceSingleton::initialize(sock);

    }

  }

  ListenerManagerFactory* listener_manager_factory = nullptr;

  if (bootstrap_.has_listener_manager()) {

    listener_manager_factory = Config::Utility::getAndCheckFactory<ListenerManagerFactory>(

        bootstrap_.listener_manager(), false);

  } else {

    listener_manager_factory = &Config::Utility::getAndCheckFactoryByName<ListenerManagerFactory>(

        Config::ServerExtensionValues::get().DEFAULT_LISTENER);

  }

  // Workers get created first so they register for thread local updates.

  listener_manager_ = listener_manager_factory->createListenerManager(

      *this, nullptr, worker_factory_, bootstrap_.enable_dispatcher_stats(), quic_stat_names_);

  // The main thread is also registered for thread local updates so that code that does not care

  // whether it runs on the main thread or on workers can still use TLS.

  thread_local_.registerThread(*dispatcher_, true);

  // We can now initialize stats for threading.

  stats_store_.initializeThreading(*dispatcher_, thread_local_);

  // It's now safe to start writing stats from the main thread's dispatcher.

  if (bootstrap_.enable_dispatcher_stats()) {

    dispatcher_->initializeStats(*stats_store_.rootScope(), "server.");

  }

  // The broad order of initialization from this point on is the following:

  // 1. Statically provisioned configuration (bootstrap) are loaded.

  // 2. Cluster manager is created and all primary clusters (i.e. with endpoint assignments

  //    provisioned statically in bootstrap, discovered through DNS or file based CDS) are

  //    initialized.

  // 3. Various services are initialized and configured using the bootstrap config.

  // 4. RTDS is initialized using primary clusters. This  allows runtime overrides to be fully

  //    configured before the rest of xDS configuration is provisioned.

  // 5. Secondary clusters (with endpoint assignments provisioned by xDS servers) are initialized.

  // 6. The rest of the dynamic configuration is provisioned.

  //

  // Please note: this order requires that RTDS is provisioned using a primary cluster. If RTDS is

  // provisioned through ADS then ADS must use primary cluster as well. This invariant is enforced

  // during RTDS initialization and invalid configuration will be rejected.

  // Runtime gets initialized before the main configuration since during main configuration

  // load things may grab a reference to the loader for later use.

  runtime_ = component_factory.createRuntime(*this, initial_config);

  initial_config.initAdminAccessLog(bootstrap_, *this);

  validation_context_.setRuntime(runtime());

  if (!runtime().snapshot().getBoolean("envoy.disallow_global_stats", false)) {

    assert_action_registration_ = Assert::addDebugAssertionFailureRecordAction(

        [this](const char*) { server_stats_->debug_assertion_failures_.inc(); });

    envoy_bug_action_registration_ = Assert::addEnvoyBugFailureRecordAction(

        [this](const char*) { server_stats_->envoy_bug_failures_.inc(); });

  }

  if (initial_config.admin().address()) {

    if (!admin_) {

      throwEnvoyExceptionOrPanic("Admin address configured but admin support compiled out");

    }

    admin_->startHttpListener(initial_config.admin().accessLogs(), options_.adminAddressPath(),

                              initial_config.admin().address(),

                              initial_config.admin().socketOptions(),

                              stats_store_.createScope("listener.admin."));

  } else {

    ENVOY_LOG(warn, "No admin address given, so no admin HTTP server started.");

  }

  if (admin_) {

    config_tracker_entry_ = admin_->getConfigTracker().add(

        "bootstrap", [this](const Matchers::StringMatcher&) { return dumpBootstrapConfig(); });

  }

  if (initial_config.admin().address()) {

    admin_->addListenerToHandler(handler_.get());

  }

  // Once we have runtime we can initialize the SSL context manager.

  ssl_context_manager_ = createContextManager("ssl_context_manager", time_source_);

  cluster_manager_factory_ = std::make_unique<Upstream::ProdClusterManagerFactory>(

      serverFactoryContext(), stats_store_, thread_local_, http_context_,

      [this]() -> Network::DnsResolverSharedPtr { return this->getOrCreateDnsResolver(); },

      *ssl_context_manager_, *secret_manager_, quic_stat_names_, *this);

  // Now the configuration gets parsed. The configuration may start setting

  // thread local data per above. See MainImpl::initialize() for why ConfigImpl

  // is constructed as part of the InstanceBase and then populated once

  // cluster_manager_factory_ is available.

  config_.initialize(bootstrap_, *this, *cluster_manager_factory_);

  // Instruct the listener manager to create the LDS provider if needed. This must be done later

  // because various items do not yet exist when the listener manager is created.

  if (bootstrap_.dynamic_resources().has_lds_config() ||

      !bootstrap_.dynamic_resources().lds_resources_locator().empty()) {

    std::unique_ptr<xds::core::v3::ResourceLocator> lds_resources_locator;

    if (!bootstrap_.dynamic_resources().lds_resources_locator().empty()) {

      lds_resources_locator =

          std::make_unique<xds::core::v3::ResourceLocator>(Config::XdsResourceIdentifier::decodeUrl(

              bootstrap_.dynamic_resources().lds_resources_locator()));

    }

    listener_manager_->createLdsApi(bootstrap_.dynamic_resources().lds_config(),

                                    lds_resources_locator.get());

  }

  // We have to defer RTDS initialization until after the cluster manager is

  // instantiated (which in turn relies on runtime...).

  runtime().initialize(clusterManager());

  clusterManager().setPrimaryClustersInitializedCb(

      [this]() { onClusterManagerPrimaryInitializationComplete(); });

  auto& stats_config = config_.statsConfig();

  for (const Stats::SinkPtr& sink : stats_config.sinks()) {

    stats_store_.addSink(*sink);

  }

  if (!stats_config.flushOnAdmin()) {

    // Some of the stat sinks may need dispatcher support so don't flush until the main loop starts.

    // Just setup the timer.

    stat_flush_timer_ = dispatcher_->createTimer([this]() -> void { flushStats(); });

    stat_flush_timer_->enableTimer(stats_config.flushInterval());

  }

  // Now that we are initialized, notify the bootstrap extensions.

  for (auto&& bootstrap_extension : bootstrap_extensions_) {

    bootstrap_extension->onServerInitialized();

  }

  // GuardDog (deadlock detection) object and thread setup before workers are

  // started and before our own run() loop runs.

  main_thread_guard_dog_ = std::make_unique<Server::GuardDogImpl>(

      *stats_store_.rootScope(), config_.mainThreadWatchdogConfig(), *api_, "main_thread");

  worker_guard_dog_ = std::make_unique<Server::GuardDogImpl>(

      *stats_store_.rootScope(), config_.workerWatchdogConfig(), *api_, "workers");

}

void InstanceBase::onClusterManagerPrimaryInitializationComplete() {

  // If RTDS was not configured the `onRuntimeReady` callback is immediately invoked.

  runtime().startRtdsSubscriptions([this]() { onRuntimeReady(); });

}

void InstanceBase::onRuntimeReady() {

  // Begin initializing secondary clusters after RTDS configuration has been applied.

  // Initializing can throw exceptions, so catch these.

  TRY_ASSERT_MAIN_THREAD { clusterManager().initializeSecondaryClusters(bootstrap_); }

  END_TRY

  CATCH(const EnvoyException& e, {

    ENVOY_LOG(warn, "Skipping initialization of secondary cluster: {}", e.what());

    shutdown();

  });

  if (bootstrap_.has_hds_config()) {

    const auto& hds_config = bootstrap_.hds_config();

    async_client_manager_ = std::make_unique<Grpc::AsyncClientManagerImpl>(

        *config_.clusterManager(), thread_local_, time_source_, *api_, grpc_context_.statNames(),

        bootstrap_.grpc_async_client_manager_config());

    TRY_ASSERT_MAIN_THREAD {

      THROW_IF_NOT_OK(Config::Utility::checkTransportVersion(hds_config));

      hds_delegate_ = std::make_unique<Upstream::HdsDelegate>(

          serverFactoryContext(), *stats_store_.rootScope(),

          Config::Utility::factoryForGrpcApiConfigSource(*async_client_manager_, hds_config,

                                                         *stats_store_.rootScope(), false)

              ->createUncachedRawAsyncClient(),

          stats_store_, *ssl_context_manager_, info_factory_);

    }

    END_TRY

    CATCH(const EnvoyException& e, {

      ENVOY_LOG(warn, "Skipping initialization of HDS cluster: {}", e.what());

      shutdown();

    });

  }

}

void InstanceBase::startWorkers() {

  // The callback will be called after workers are started.

  listener_manager_->startWorkers(*worker_guard_dog_, [this]() {

    if (isShutdown()) {

      return;

    }

    initialization_timer_->complete();

    // Update server stats as soon as initialization is done.

    updateServerStats();

    workers_started_ = true;

    hooks_.onWorkersStarted();

    // At this point we are ready to take traffic and all listening ports are up. Notify our

    // parent if applicable that they can stop listening and drain.

    restarter_.drainParentListeners();

    drain_manager_->startParentShutdownSequence();

  });

}

Runtime::LoaderPtr InstanceUtil::createRuntime(Instance& server,

                                               Server::Configuration::Initial& config) {

#ifdef ENVOY_ENABLE_YAML

  ENVOY_LOG(info, "runtime: {}", MessageUtil::getYamlStringFromMessage(config.runtime()));

#endif

  return std::make_unique<Runtime::LoaderImpl>(

      server.dispatcher(), server.threadLocal(), config.runtime(), server.localInfo(),

      server.stats(), server.api().randomGenerator(),

      server.messageValidationContext().dynamicValidationVisitor(), server.api());

}

void InstanceBase::loadServerFlags(const absl::optional<std::string>& flags_path) {

  if (!flags_path) {

    return;

  }

  ENVOY_LOG(info, "server flags path: {}", flags_path.value());

  if (api_->fileSystem().fileExists(flags_path.value() + "/drain")) {

    ENVOY_LOG(info, "starting server in drain mode");

    InstanceBase::failHealthcheck(true);

  }

}

RunHelper::RunHelper(Instance& instance, const Options& options, Event::Dispatcher& dispatcher,

                     Upstream::ClusterManager& cm, AccessLog::AccessLogManager& access_log_manager,

                     Init::Manager& init_manager, OverloadManager& overload_manager,

                     std::function<void()> post_init_cb)

    : init_watcher_("RunHelper", [&instance, post_init_cb]() {

        if (!instance.isShutdown()) {

          post_init_cb();

        }

      }) {

  // Setup signals.

  // Since signals are not supported on Windows we have an internal definition for `SIGTERM`

  // On POSIX it resolves as expected to SIGTERM

  // On Windows we use it internally for all the console events that indicate that we should

  // terminate the process.

  if (options.signalHandlingEnabled()) {

    sigterm_ = dispatcher.listenForSignal(ENVOY_SIGTERM, [&instance]() {

      ENVOY_LOG(warn, "caught ENVOY_SIGTERM");

      instance.shutdown();

    });

#ifndef WIN32

    sigint_ = dispatcher.listenForSignal(SIGINT, [&instance]() {

      ENVOY_LOG(warn, "caught SIGINT");

      instance.shutdown();

    });

    sig_usr_1_ = dispatcher.listenForSignal(SIGUSR1, [&access_log_manager]() {

      ENVOY_LOG(info, "caught SIGUSR1. Reopening access logs.");

      access_log_manager.reopen();

    });

    sig_hup_ = dispatcher.listenForSignal(SIGHUP, []() {

      ENVOY_LOG(warn, "caught and eating SIGHUP. See documentation for how to hot restart.");

    });

#endif

  }

  // Start overload manager before workers.

  overload_manager.start();

  // If there is no global limit to the number of active connections, warn on startup.

  if (!overload_manager.getThreadLocalOverloadState().isResourceMonitorEnabled(

          Server::OverloadProactiveResourceName::GlobalDownstreamMaxConnections) &&

      !instance.runtime().snapshot().get(Network::TcpListenerImpl::GlobalMaxCxRuntimeKey)) {

    ENVOY_LOG(warn, "There is no configured limit to the number of allowed active downstream "

                    "connections. Configure a "

                    "limit in `envoy.resource_monitors.downstream_connections` resource monitor.");

  }

  // Register for cluster manager init notification. We don't start serving worker traffic until

  // upstream clusters are initialized which may involve running the event loop. Note however that

  // this can fire immediately if all clusters have already initialized. Also note that we need

  // to guard against shutdown at two different levels since SIGTERM can come in once the run loop

  // starts.

  cm.setInitializedCb([&instance, &init_manager, &cm, this]() {

    if (instance.isShutdown()) {

      return;

    }

    const auto type_url = Config::getTypeUrl<envoy::config::route::v3::RouteConfiguration>();

    // Pause RDS to ensure that we don't send any requests until we've

    // subscribed to all the RDS resources. The subscriptions happen in the init callbacks,

    // so we pause RDS until we've completed all the callbacks.

    Config::ScopedResume maybe_resume_rds;

    if (cm.adsMux()) {

      maybe_resume_rds = cm.adsMux()->pause(type_url);

    }

    ENVOY_LOG(info, "all clusters initialized. initializing init manager");

    init_manager.initialize(init_watcher_);

    // Now that we're execute all the init callbacks we can resume RDS

    // as we've subscribed to all the statically defined RDS resources.

    // This is done by tearing down the maybe_resume_rds Cleanup object.

  });

}

void InstanceBase::run() {

  // RunHelper exists primarily to facilitate testing of how we respond to early shutdown during

  // startup (see RunHelperTest in server_test.cc).

  const auto run_helper = RunHelper(*this, options_, *dispatcher_, clusterManager(),

                                    access_log_manager_, init_manager_, overloadManager(), [this] {

                                      notifyCallbacksForStage(Stage::PostInit);

                                      startWorkers();

                                    });

  // Run the main dispatch loop waiting to exit.

  ENVOY_LOG(info, "starting main dispatch loop");

  auto watchdog = main_thread_guard_dog_->createWatchDog(api_->threadFactory().currentThreadId(),

                                                         "main_thread", *dispatcher_);

  dispatcher_->post([this] { notifyCallbacksForStage(Stage::Startup); });

  dispatcher_->run(Event::Dispatcher::RunType::Block);

  ENVOY_LOG(info, "main dispatch loop exited");

  main_thread_guard_dog_->stopWatching(watchdog);

  watchdog.reset();

  terminate();

}

void InstanceBase::terminate() {

  if (terminated_) {

    return;

  }

  terminated_ = true;

  // Before starting to shutdown anything else, stop slot destruction updates.

  thread_local_.shutdownGlobalThreading();

  // Before the workers start exiting we should disable stat threading.

  stats_store_.shutdownThreading();

  // TODO: figure out the correct fix: https://github.com/envoyproxy/envoy/issues/15072.

  std::vector<std::string> muxes = {

      "envoy.config_mux.new_grpc_mux_factory", "envoy.config_mux.grpc_mux_factory",

      "envoy.config_mux.delta_grpc_mux_factory", "envoy.config_mux.sotw_grpc_mux_factory"};

  for (const auto& name : muxes) {

    auto* factory = Config::Utility::getFactoryByName<Config::MuxFactory>(name);

    if (factory) {

      factory->shutdownAll();

    }

  }

  if (overload_manager_) {

    overload_manager_->stop();

  }

  // Shutdown all the workers now that the main dispatch loop is done.

  if (listener_manager_ != nullptr) {

    listener_manager_->stopWorkers();

  }

  // Only flush if we have not been hot restarted.

  if (stat_flush_timer_) {

    flushStats();

  }

  if (config_.clusterManager() != nullptr) {

    config_.clusterManager()->shutdown();

  }

  handler_.reset();

  thread_local_.shutdownThread();

  restarter_.shutdown();

  ENVOY_LOG(info, "exiting");

  ENVOY_FLUSH_LOG();

  FatalErrorHandler::clearFatalActionsOnTerminate();

}

Runtime::Loader& InstanceBase::runtime() { return *runtime_; }

void InstanceBase::shutdown() {

  ENVOY_LOG(info, "shutting down server instance");

  shutdown_ = true;

  restarter_.sendParentTerminateRequest();

  notifyCallbacksForStage(Stage::ShutdownExit, [this] { dispatcher_->exit(); });

}