com.turn.splicer.SuggestHttpWorker.java Source code

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Here is the source code for com.turn.splicer.SuggestHttpWorker.java

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/**
 * Copyright 2015-2016 The Splicer Query Engine Authors
 *
 * 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 com.turn.splicer;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * Takes a api/suggest query string and runs it against a random TSD node,
 * returns the result of the query
 *
 * TODO: needs to be refactored with HttpWorker, there is a lot of duplicate logic
 * TODO: error reporting differs from regular TSDB - no error message for invalid type
 */
public class SuggestHttpWorker implements Callable<String> {
    private static final Logger LOG = LoggerFactory.getLogger(SuggestHttpWorker.class);

    private final String suggestQuery;

    private final String[] hosts;

    private static final Random RANDOM_GENERATOR = new Random();

    public SuggestHttpWorker(String queryString) {
        this.suggestQuery = queryString;

        Set<String> hosts = HttpWorker.TSDMap.keySet();
        if (hosts.size() == 0) {
            throw new NullPointerException("No Query Hosts. TSDMap.size = 0");
        }

        this.hosts = new String[hosts.size()];
        int i = 0;
        for (String h : hosts) {
            this.hosts[i] = h;
            i++;
        }
    }

    @Override
    public String call() throws Exception {
        LinkedBlockingQueue<String> TSDs;

        //TODO: have it implement its own RegionChecker to get hbase locality looking for metric names
        //lets have it just pick a random host
        String hostname = getRandomHost();
        TSDs = HttpWorker.TSDMap.get(hostname);

        if (TSDs == null) {
            LOG.error("We are not running TSDs on regionserver={}. Choosing a random host failed", hostname);
            return "{'error': 'Choice of hostname=" + hostname + " failed.'}";
        }

        String server = TSDs.take();
        String uri = "http://" + server + "/api/suggest?" + suggestQuery;

        CloseableHttpClient postman = HttpClientBuilder.create().build();
        try {
            HttpGet getRequest = new HttpGet(uri);

            LOG.info("Sending query=" + uri + " to TSD running on host=" + hostname);

            HttpResponse response = postman.execute(getRequest);

            if (response.getStatusLine().getStatusCode() != 200) {
                throw new RuntimeException(
                        "Failed : HTTP error code : " + response.getStatusLine().getStatusCode());
            }

            List<String> dl = IOUtils.readLines(response.getEntity().getContent());
            String result = StringUtils.join(dl, "");
            LOG.info("Result={}", result);

            return result;
        } finally {
            IOUtils.closeQuietly(postman);

            TSDs.put(server);
            LOG.info("Returned {} into the available queue", server);
        }
    }

    /**
     * Chooses a random number between 0 - (host.length-1) inclusive
     * returns that index in the hosts list
     * @return
     */
    private String getRandomHost() {
        return hosts[RANDOM_GENERATOR.nextInt(hosts.length)];
    }
}