core/src/main/java/org/apache/oozie/servlet/SLAServlet.java

/**
 * 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 org.apache.oozie.servlet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.oozie.ErrorCode;
import org.apache.oozie.SLAEventBean;
import org.apache.oozie.client.OozieClient;
import org.apache.oozie.client.rest.RestConstants;
import org.apache.oozie.command.CommandException;
import org.apache.oozie.command.coord.SLAEventsXCommand;
import org.apache.oozie.util.XLog;
import org.apache.oozie.util.XmlUtils;
import org.jdom.Element;

@SuppressWarnings("deprecation")
public class SLAServlet extends JsonRestServlet {

    private static final Set<String> SLA_FILTER_NAMES = new HashSet<String>();

    static {
        SLA_FILTER_NAMES.add(OozieClient.FILTER_JOBID);
        SLA_FILTER_NAMES.add(OozieClient.FILTER_APPNAME);
    }

    private static final String INSTRUMENTATION_NAME = "sla";

    private static final JsonRestServlet.ResourceInfo RESOURCES_INFO[] = new JsonRestServlet.ResourceInfo[1];

    static {
        RESOURCES_INFO[0] = new JsonRestServlet.ResourceInfo("", Arrays.asList("GET"), Arrays.asList(
                new JsonRestServlet.ParameterInfo(RestConstants.SLA_GT_SEQUENCE_ID, String.class, false, Arrays
                        .asList("GET")), new JsonRestServlet.ParameterInfo(RestConstants.MAX_EVENTS, String.class,
                        false, Arrays.asList("GET")), new JsonRestServlet.ParameterInfo(
                        RestConstants.JOBS_FILTER_PARAM, String.class, false, Arrays.asList("GET"))));
    }

    public SLAServlet() {
        super(INSTRUMENTATION_NAME, RESOURCES_INFO);
    }

    public SLAServlet(String instrumentationName, ResourceInfo... resourcesInfo) {
        super(instrumentationName, resourcesInfo);
    }

    /**
     * Return information about SLA Events.
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        Element eResponse = new Element("sla-message");
        List<SLAEventBean> slaEvntList = null;

        try {
            stopCron();
            String gtSequenceNum = request.getParameter(RestConstants.SLA_GT_SEQUENCE_ID);
            String strMaxEvents = request.getParameter(RestConstants.MAX_EVENTS);
            String filter = request.getParameter(RestConstants.JOBS_FILTER_PARAM);
            Map<String, List<String>> filterList = parseFilter(filter, SLA_FILTER_NAMES);

            int maxNoEvents = 100; // Default
            XLog.getLog(getClass()).debug(
                    "Got SLA GET request for :" + gtSequenceNum + " and max-events :" + strMaxEvents);
            if (strMaxEvents != null && strMaxEvents.length() > 0) {
                maxNoEvents = Integer.parseInt(strMaxEvents);
            }

            if (gtSequenceNum != null) {
                long seqId = Long.parseLong(gtSequenceNum);
                stopCron();
                SLAEventsXCommand seCommand = new SLAEventsXCommand(seqId, maxNoEvents, filterList);
                slaEvntList = seCommand.call();
                long lastSeqId = seCommand.getLastSeqId();

                eResponse = new Element("sla-message");
                for (SLAEventBean event : slaEvntList) {
                    eResponse.addContent(event.toXml());
                }
                Element eLastSeq = new Element("last-sequence-id");
                eLastSeq.addContent(String.valueOf(lastSeqId));
                eResponse.addContent(eLastSeq);
                XLog.getLog(getClass()).debug("Writing back SLA Servlet  Caller with last-seq-id " + lastSeqId);
                startCron();
            }
            else {
                XLog.getLog(getClass()).error("gt-sequence-id parameter is not specified in the http request");
                throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ErrorCode.E0401,
                        "gt-sequence-id parameter is not specified in the http request");
            }
            startCron();
            response.setContentType(XML_UTF8);
            response.setStatus(HttpServletResponse.SC_OK);
            response.getWriter().write(XmlUtils.prettyPrint(eResponse) + "\n");
        }
        catch (CommandException ce) {
            ce.printStackTrace();
            XLog.getLog(getClass()).error("Command exception ", ce);
            throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ce);
        }
        catch (RuntimeException re) {
            re.printStackTrace();
            XLog.getLog(getClass()).error("Runtime error ", re);
            throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ErrorCode.E0307, re.getMessage());
        }
    }

    protected Map<String, List<String>> parseFilter(String filterString, Set<String> allowedFilters) throws ServletException {
        Map<String, List<String>> map = new HashMap<String, List<String>>();
        if (filterString != null) {
            StringTokenizer st = new StringTokenizer(filterString, ";");
            while (st.hasMoreTokens()) {
                String token = st.nextToken();
                if (token.contains("=")) {
                    String[] pair = token.split("=");
                    if (pair.length != 2) {
                        throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ErrorCode.E0401,
                                "elements must be semicolon-separated name=value pairs");
                    }
                    if (!allowedFilters.contains(pair[0])) {
                        throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ErrorCode.E0401,
                                "invalid/unsupported names in filter");
                    }
                    List<String> list = map.get(pair[0]);
                    if (list == null) {
                        list = new ArrayList<String>();
                        map.put(pair[0], list);
                    }
                    list.add(pair[1]);
                }
                else {
                    throw new XServletException(HttpServletResponse.SC_BAD_REQUEST, ErrorCode.E0401,
                            "elements must be semicolon-separated name=value pairs");
                }
            }
        }
        return map;
    }

}