org.selman.tweetamo.TweetamoServer.java Source code

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Here is the source code for org.selman.tweetamo.TweetamoServer.java

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/*
 * Copyright 2013 Daniel Selman
 * 
 * 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 org.selman.tweetamo;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.util.Properties;
import java.util.UUID;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.amazonaws.AmazonClientException;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.ClasspathPropertiesFileCredentialsProvider;
import com.amazonaws.auth.InstanceProfileCredentialsProvider;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorFactory;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.InitialPositionInStream;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.KinesisClientLibConfiguration;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker;

/**
 * Sample Kinesis Application.
 */
public final class TweetamoServer {

    private static final String DEFAULT_APP_NAME = "TweetamoServer";
    private static final String DEFAULT_STREAM_NAME = "tweetamo";
    private static final String DEFAULT_KINESIS_ENDPOINT = "https://kinesis.us-east-1.amazonaws.com";

    // Initial position in the stream when the application starts up for the first time.
    // Position can be one of LATEST (most recent data) or TRIM_HORIZON (oldest available data)
    private static final InitialPositionInStream DEFAULT_INITIAL_POSITION = InitialPositionInStream.TRIM_HORIZON;

    private static String applicationName = DEFAULT_APP_NAME;
    private static String streamName = DEFAULT_STREAM_NAME;
    private static String kinesisEndpoint = DEFAULT_KINESIS_ENDPOINT;
    private static InitialPositionInStream initialPositionInStream = DEFAULT_INITIAL_POSITION;

    private static KinesisClientLibConfiguration kinesisClientLibConfiguration;

    private static final Log LOG = LogFactory.getLog(TweetamoServer.class);

    /**
     * 
     */
    private TweetamoServer() {
        super();
    }

    /**
     * @param args Property file with config overrides (e.g. application name, stream name)
     * @throws IOException Thrown if we can't read properties from the specified properties file
     */
    public static void main(String[] args) throws IOException {
        String propertiesFile = null;

        if (args.length > 1) {
            System.err.println("Usage: java " + TweetamoServer.class.getName() + " <propertiesFile>");
            System.exit(1);
        } else if (args.length == 1) {
            propertiesFile = args[0];
        }

        configure(propertiesFile);

        System.out.println("Starting " + applicationName);
        LOG.info("Running " + applicationName + " to process stream " + streamName);

        IRecordProcessorFactory recordProcessorFactory = new TweetamoRecordProcessorFactory();
        Worker worker = new Worker(recordProcessorFactory, kinesisClientLibConfiguration);

        int exitCode = 0;
        try {
            worker.run();
        } catch (Throwable t) {
            LOG.error("Caught throwable while processing data.", t);
            exitCode = 1;
        }
        System.exit(exitCode);
    }

    private static void configure(String propertiesFile) throws IOException {

        if (propertiesFile != null) {
            loadProperties(propertiesFile);
        }

        // ensure the JVM will refresh the cached IP values of AWS resources (e.g. service endpoints).
        java.security.Security.setProperty("networkaddress.cache.ttl", "60");

        String workerId = InetAddress.getLocalHost().getCanonicalHostName() + ":" + UUID.randomUUID();
        LOG.info("Using workerId: " + workerId);

        // Get credentials from IMDS. If unsuccessful, get them from the classpath. 
        AWSCredentialsProvider credentialsProvider = null;
        try {
            credentialsProvider = new InstanceProfileCredentialsProvider();
            // Verify we can fetch credentials from the provider
            credentialsProvider.getCredentials();
            LOG.info("Obtained credentials from the IMDS.");
        } catch (AmazonClientException e) {
            LOG.info("Unable to obtain credentials from the IMDS, trying classpath properties", e);
            credentialsProvider = new ClasspathPropertiesFileCredentialsProvider();
            // Verify we can fetch credentials from the provider
            credentialsProvider.getCredentials();
            LOG.info("Obtained credentials from the properties file.");
        }

        LOG.info("Using credentials with access key id: "
                + credentialsProvider.getCredentials().getAWSAccessKeyId());
        kinesisClientLibConfiguration = new KinesisClientLibConfiguration(applicationName, streamName,
                credentialsProvider, workerId);
    }

    /**
     * @param propertiesFile
     * @throws IOException Thrown when we run into issues reading properties
     */
    private static void loadProperties(String propertiesFile) throws IOException {
        FileInputStream inputStream = new FileInputStream(propertiesFile);
        Properties properties = new Properties();
        try {
            properties.load(inputStream);
        } finally {
            inputStream.close();
        }

        String appNameOverride = properties.getProperty(ConfigKeys.APPLICATION_NAME_KEY);
        if (appNameOverride != null) {
            applicationName = appNameOverride;
        }
        LOG.info("Using application name " + applicationName);

        String streamNameOverride = properties.getProperty(ConfigKeys.STREAM_NAME_KEY);
        if (streamNameOverride != null) {
            streamName = streamNameOverride;
        }
        LOG.info("Using stream name " + streamName);

        String kinesisEndpointOverride = properties.getProperty(ConfigKeys.KINESIS_ENDPOINT_KEY);
        if (kinesisEndpointOverride != null) {
            kinesisEndpoint = kinesisEndpointOverride;
        }
        String initialPositionOverride = properties.getProperty(ConfigKeys.INITIAL_POSITION_IN_STREAM_KEY);
        if (initialPositionOverride != null) {
            initialPositionInStream = InitialPositionInStream.valueOf(initialPositionOverride);
        }
        LOG.info("Using initial position " + initialPositionInStream.toString()
                + " (if a checkpoint is not found).");
    }

}