Ec2CustomNodeAttributes.java

/*
 * Licensed to ElasticSearch and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. ElasticSearch 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.
 */

package org.elasticsearch.cloud.aws.node;

import com.google.common.collect.Maps;
import com.google.common.io.Closeables;
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.cloud.aws.AwsEc2Service;
import org.elasticsearch.cluster.node.DiscoveryNodeService;
import org.elasticsearch.common.component.AbstractComponent;
import org.elasticsearch.common.settings.Settings;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;

/**
 */
public class Ec2CustomNodeAttributes extends AbstractComponent implements DiscoveryNodeService.CustomAttributesProvider {

    public Ec2CustomNodeAttributes(Settings settings) {
        super(settings);
    }

    @Override
    public Map<String, String> buildAttributes() {
        if (!settings.getAsBoolean("cloud.node.auto_attributes", false)) {
            return null;
        }
        Map<String, String> ec2Attributes = Maps.newHashMap();

        URLConnection urlConnection;
        InputStream in = null;
        try {
            URL url = new URL(AwsEc2Service.EC2_METADATA_URL + "placement/availability-zone");
            logger.debug("obtaining ec2 [placement/availability-zone] from ec2 meta-data url {}", url);
            urlConnection = url.openConnection();
            urlConnection.setConnectTimeout(2000);
            in = urlConnection.getInputStream();
            BufferedReader urlReader = new BufferedReader(new InputStreamReader(in));

            String metadataResult = urlReader.readLine();
            if (metadataResult == null || metadataResult.length() == 0) {
                logger.error("no ec2 metadata returned from {}", url);
                return null;
            }
            ec2Attributes.put("aws_availability_zone", metadataResult);
        } catch (IOException e) {
            logger.debug("failed to get metadata for [placement/availability-zone]: " + ExceptionsHelper.detailedMessage(e));
        } finally {
            Closeables.closeQuietly(in);
        }

        return ec2Attributes;
    }
}