Java tutorial
/** * Licensed to DigitalPebble Ltd under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * DigitalPebble 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 com.digitalpebble.stormcrawler.aws.s3; import java.util.Map; import org.apache.commons.lang.StringUtils; import org.apache.storm.metric.api.MultiCountMetric; import org.apache.storm.task.OutputCollector; import org.apache.storm.task.TopologyContext; import org.apache.storm.topology.OutputFieldsDeclarer; import org.apache.storm.topology.base.BaseRichBolt; import org.apache.storm.tuple.Fields; import com.amazonaws.ClientConfiguration; import com.amazonaws.auth.AWSCredentials; import com.amazonaws.auth.AWSCredentialsProvider; import com.amazonaws.auth.DefaultAWSCredentialsProviderChain; import com.amazonaws.regions.RegionUtils; import com.amazonaws.services.s3.AmazonS3Client; import com.digitalpebble.stormcrawler.util.ConfUtils; @SuppressWarnings("serial") public abstract class AbstractS3CacheBolt extends BaseRichBolt { public static final String S3_PREFIX = "s3."; public static final String ENDPOINT = S3_PREFIX + "endpoint"; public static final String BUCKET = S3_PREFIX + "bucket"; // is the region needed? public static final String REGION = S3_PREFIX + "region"; public static final String INCACHE = S3_PREFIX + "inCache"; protected OutputCollector _collector; protected MultiCountMetric eventCounter; protected AmazonS3Client client; protected String bucketName; /** Returns an S3 client given the configuration **/ public static AmazonS3Client getS3Client(Map conf) { AWSCredentialsProvider provider = new DefaultAWSCredentialsProviderChain(); AWSCredentials credentials = provider.getCredentials(); ClientConfiguration config = new ClientConfiguration(); AmazonS3Client client = new AmazonS3Client(credentials, config); String regionName = ConfUtils.getString(conf, REGION); if (StringUtils.isNotBlank(regionName)) { client.setRegion(RegionUtils.getRegion(regionName)); } String endpoint = ConfUtils.getString(conf, ENDPOINT); if (StringUtils.isNotBlank(endpoint)) { client.setEndpoint(endpoint); } return client; } @Override public void prepare(Map conf, TopologyContext context, OutputCollector collector) { _collector = collector; client = getS3Client(conf); } @Override public void declareOutputFields(OutputFieldsDeclarer declarer) { declarer.declare(new Fields("url", "content", "metadata")); } }