com.pinterest.terrapin.controller.FileSetStatusServlet.java Source code

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Here is the source code for com.pinterest.terrapin.controller.FileSetStatusServlet.java

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/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.pinterest.terrapin.controller;

import com.google.common.collect.Lists;
import com.pinterest.terrapin.TerrapinUtil;
import com.pinterest.terrapin.zookeeper.FileSetInfo;
import com.pinterest.terrapin.zookeeper.ViewInfo;
import com.pinterest.terrapin.zookeeper.ZooKeeperManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * This class implements a servlet to check status for a specific file set
 */
public class FileSetStatusServlet extends HttpServlet {

    public static final String BASE_URI = "/status/file_sets";
    private static final Pattern uriPattern = Pattern.compile(BASE_URI + "/(.*)");
    private static final Logger LOG = LoggerFactory.getLogger(FileSetStatusServlet.class);

    /**
     * Get file set name from a giving uri.
     * E.g. Giving '/status/file_sets/image_scores', it returns 'image_scores'
     * @param uri the uri to be parsed
     * @return file set name
     */
    public static String parseFileSetFromURI(String uri) {
        Matcher matcher = uriPattern.matcher(uri);
        if (matcher.matches()) {
            return matcher.group(1);
        }
        return null;
    }

    /**
     * Get partition map for a specific file set as pretty printing JSON string
     * @param zkManager ZookeeperManager instance
     * @param fileSetInfo file set information
     * @return JSON string
     * @throws IOException if dumping process raises any exceptions.
     */
    public static String getPartitionMapJsonString(ZooKeeperManager zkManager, FileSetInfo fileSetInfo)
            throws IOException {
        if (fileSetInfo.servingInfo == null) {
            return "{}";
        }
        ViewInfo viewInfo = zkManager.getViewInfo(fileSetInfo.servingInfo.helixResource);
        if (viewInfo == null) {
            return "{}";
        }
        return viewInfo.toPrettyPrintingJson();
    }

    /**
     * Get all missing partitions
     * @param zkManager ZookeeperManager instance
     * @param fileSetInfo file set information
     * @return list of missing partitions
     */
    public static List<Integer> getMissingPartitions(ZooKeeperManager zkManager, FileSetInfo fileSetInfo) {
        if (fileSetInfo.servingInfo == null) {
            return Lists.newArrayListWithCapacity(0);
        }
        ViewInfo viewInfo = zkManager.getViewInfo(fileSetInfo.servingInfo.helixResource);
        if (viewInfo == null) {
            return Lists.newArrayListWithCapacity(0);
        }
        List<Integer> missingPartitions = new ArrayList<Integer>();
        for (int i = 0; i < fileSetInfo.servingInfo.numPartitions; i++) {
            String partitionName = TerrapinUtil.getViewPartitionName(fileSetInfo.servingInfo.helixResource, i);
            if (!viewInfo.isOnlinePartition(partitionName)) {
                missingPartitions.add(i);
            }
        }
        return missingPartitions;
    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.setContentType("text/html");
        ServletContext context = getServletContext();

        ZooKeeperManager zkManager = (ZooKeeperManager) context.getAttribute("zookeeper-manager");
        String clusterName = (String) context.getAttribute("cluster_name");
        String fileSet = parseFileSetFromURI(request.getRequestURI());
        FileSetInfo fileSetInfo = zkManager.getFileSetInfo(fileSet);
        String rawJson = fileSetInfo.toPrettyPrintingJson();
        String partitionMapJson = getPartitionMapJsonString(zkManager, fileSetInfo);

        FileSetStatusTmpl fileSetStatusTmpl = new FileSetStatusTmpl();
        fileSetStatusTmpl.render(response.getWriter(), clusterName, fileSet, rawJson, partitionMapJson,
                getMissingPartitions(zkManager, fileSetInfo));
    }
}