src/cli/resolve.cpp

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <iostream>

#include <process/future.hpp>

#include <stout/duration.hpp>
#include <stout/flags.hpp>
#include <stout/none.hpp>
#include <stout/nothing.hpp>
#include <stout/path.hpp>
#include <stout/strings.hpp>
#include <stout/try.hpp>

#include "master/detector.hpp"

#include "messages/messages.hpp"

using namespace mesos;
using namespace mesos::internal;

using process::Future;

using std::cerr;
using std::cout;
using std::endl;
using std::string;


int main(int argc, char** argv)
{
  flags::FlagsBase flags;
  flags.setUsageMessage("Usage: " + Path(argv[0]).basename() + " <master>");

  Duration timeout;
  flags.add(&timeout,
            "timeout",
            "How long to wait to resolve master",
            Seconds(5));

  // TODO(marco): `verbose` is also a great candidate for FlagsBase.
  bool verbose;
  flags.add(&verbose,
            "verbose",
            "Be verbose",
            false);

  // Load flags from environment and command line, and remove
  // them from argv.
  Try<Nothing> load = flags.load(None(), &argc, &argv);

  if (load.isError()) {
    cerr << flags.usage(load.error()) << endl;
    return EXIT_FAILURE;
  }

  if (flags.help) {
    cout << flags.usage() << endl;
    return EXIT_SUCCESS;
  }

  // 'master' argument must be the only argument left after parsing.
  if (argc != 2) {
    cerr << flags.usage("There must be only one argument: <master>") << endl;
    return EXIT_FAILURE;
  }

  string master = argv[1];
  Try<MasterDetector*> detector = MasterDetector::create(master);

  if (detector.isError()) {
    cerr << "Failed to create a master detector: " << detector.error() << endl;
    return EXIT_FAILURE;
  }

  Future<Option<MasterInfo> > masterInfo = detector.get()->detect();

  if (!masterInfo.await(timeout)) {
    cerr << "Failed to detect master from '" << master
         << "' within " << timeout << endl;
    return -1;
  } else {
    CHECK(!masterInfo.isDiscarded());

    if (masterInfo.isFailed()) {
      cerr << "Failed to detect master from '" << master
           << "': " << masterInfo.failure() << endl;
      return EXIT_FAILURE;
    }
  }

  // The future is not satisfied unless the result is Some.
  CHECK_SOME(masterInfo.get());
  cout << strings::remove(masterInfo.get().get().pid(), "master@") << endl;

  return EXIT_SUCCESS;
}