jp.classmethod.aws.InstanceMetadataFactoryBean.java Source code

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Here is the source code for jp.classmethod.aws.InstanceMetadataFactoryBean.java

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/*
 * Copyright 2013-2014 Classmethod, Inc.
 *
 * Licensed 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 jp.classmethod.aws;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import com.google.gson.Gson;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.FactoryBean;

/**
 * Spring factory bean for {@link InstanceMetadata}.
 *
 * @since 1.0
 * @author daisuke
 */
public class InstanceMetadataFactoryBean implements FactoryBean<InstanceMetadata> {

    private static Logger logger = LoggerFactory.getLogger(InstanceMetadataFactoryBean.class);

    private static final String USER_DATA_URL = "http://169.254.169.254/latest/dynamic/instance-identity/document";

    private static final int TIMEOUT = 1000;

    @Override
    public InstanceMetadata getObject() {
        Gson gson = new Gson();
        InstanceMetadata metadata = null;
        try (Reader reader = createUserDataReader()) {
            metadata = gson.fromJson(reader, InstanceMetadata.class);
            return metadata;
        } catch (MalformedURLException e) {
            throw new Error(e);
        } catch (IOException e) {
            logger.warn("IOException {}", e.getMessage());
        } catch (Exception e) {
            logger.error("Exception {}", e.getMessage());
        }

        if (metadata == null) {
            metadata = new InstanceMetadata();
            metadata.setInstanceId("LOCAL");
        }

        logger.info("loaded {}", metadata);
        return metadata;
    }

    private Reader createUserDataReader() throws IOException, MalformedURLException {
        URLConnection conn = new URL(USER_DATA_URL).openConnection();
        conn.setReadTimeout(TIMEOUT);
        conn.setConnectTimeout(TIMEOUT);
        conn.connect();
        return new BufferedReader(new InputStreamReader(conn.getInputStream()));
    }

    @Override
    public Class<?> getObjectType() {
        return InstanceMetadata.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }
}