Connection.h

/*
 *  Copyright (c) 2014, 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/Memory.h>

#include "common/thrift/thrift/gen-cpp2/MonitorAsyncClient.h"

DECLARE_string(counter_name);
DECLARE_int32(counter_threshold);

namespace facebook {
namespace windtunnel {
namespace treadmill {

/**
 * Specializations of this template should implement:
 *
 * bool isReady();
 *
 * folly::Future<Service::Reply>
 * sendRequest(std::unique_ptr<typename Service::Request>&& request);
 *
 * */
template <class Service>
class Connection {
 public:
  /**
   * Sample implementation below shows how to wait for a specific counter
   * value to cross a threshold
   * e.g. usage: --wait_for_target_ready --counter_threshold 10
   * --counter_name thrift.accepted_connections.count
   * */

  bool isReady() const {
    if (!FLAGS_counter_name.empty()) {
      int64_t value = client_->sync_getCounter(FLAGS_counter_name);
      if (value < FLAGS_counter_threshold) {
        LOG(INFO) << "Threshold: " << FLAGS_counter_threshold
                  << " Counter: " << FLAGS_counter_name << " Value: " << value;
        return false;
      }
    }
    return true;
  }

 private:
  std::unique_ptr<facebook::thrift::MonitorAsyncClient> client_;
};

} // namespace treadmill
} // namespace windtunnel
} // namespace facebook