Service.h

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/*
 *  Copyright (c) 2015-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 *
 */
#pragma once

#include <folly/io/async/EventBase.h>
#include <list>
#include <memory>

namespace proxygen {

class ServiceWorker;
class RequestWorker;

/*
 * A Service object represents a network service running in proxygen.
 *
 * The Service object is primarily a construct used for managing startup and
 * shutdown.  The RunProxygen() call will accept a list of Service objects, and
 * will invoke start() on each service to start them.  When shutdown has been
 * requested, it will invoke failHealthChecks() on each service followed (after
 * some period of time) by stopAccepting().
 *
 * All of these methods are invoked from the main thread.
 */
class Service {
 public:
  Service();
  virtual ~Service();

  virtual void init(folly::EventBase* mainEventBase,
                    const std::list<RequestWorker*>& workers) = 0;


  virtual void finishInit() {}


  virtual void startAccepting() {}

  virtual void failHealthChecks() {}

  virtual void stopAccepting() = 0;

  virtual void pauseListening() {}

  virtual void dropConnections(double /*pct*/) {}

  virtual void forceStop() {}

  virtual void initWorkerState(RequestWorker*) {}

  virtual void cleanupWorkerState(RequestWorker* /*worker*/) {}

  void addServiceWorker(std::unique_ptr<ServiceWorker> worker,
                        RequestWorker* reqWorker);

  const std::list<std::unique_ptr<ServiceWorker>>& getServiceWorkers() const {
    return workers_;
  }

  void clearServiceWorkers();

  void addWorkerEventBase(folly::EventBase* evb) {
    workerEvbs_.push_back(evb);
  }

  const std::vector<folly::EventBase*>& getWorkerEventBases() {
    return workerEvbs_;
  }

 private:
  // Forbidden copy constructor and assignment opererator
  Service(Service const &) = delete;
  Service& operator=(Service const &) = delete;

  // Workers
  std::list<std::unique_ptr<ServiceWorker>> workers_;
  std::vector<folly::EventBase*> workerEvbs_;
};

} // proxygen