lang/cs/Org.Apache.REEF.Common/Evaluator/DefaultYarnClusterHttpDriverConnection.cs

// Licensed to the Apache Software Foundation (ASF) under one
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// 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
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using System;
using Org.Apache.REEF.Tang.Annotations;
using Org.Apache.REEF.Utilities;

namespace Org.Apache.REEF.Common.Evaluator
{
    public sealed class DefaultYarnClusterHttpDriverConnection : IDriverConnection
    {
        private readonly string _applicationId;

        [Inject]
        private DefaultYarnClusterHttpDriverConnection()
        {
            _applicationId = Environment.GetEnvironmentVariable(Constants.ReefYarnApplicationIdEnvironmentVariable);
        }

        public DriverInformation GetDriverInformation()
        {
            if (string.IsNullOrWhiteSpace(_applicationId))
            {
                throw new ApplicationException("Could not fetch the application ID from YARN's container environment variables.");
            }

            // e.g., http://headnodehost:9014/proxy/application_1407519727821_0012/reef/v1/driver
            Uri queryUri = new Uri(
                string.Concat(
                Constants.HDInsightClusterHttpEndpointBaseUri,
                _applicationId + "/",
                Constants.HttpReefUriSpecification,
                Constants.HttpDriverUriTarget));
            return DriverInformation.GetDriverInformationFromHttp(queryUri);
        }
    }
}