org.apache.ambari.servicemonitor.reporting.restapi.RestStatusServlet.java Source code

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Here is the source code for org.apache.ambari.servicemonitor.reporting.restapi.RestStatusServlet.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 org.apache.ambari.servicemonitor.reporting.restapi;

import org.apache.ambari.servicemonitor.reporting.ProbeStatus;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.jackson.map.ObjectMapper;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;

public class RestStatusServlet extends HttpServlet {
    private static final Log LOG = LogFactory.getLog(RestServer.class);
    public static final String LIVE = "live";

    private ServletContext ctx;
    private RestReporter owner;
    ProbeStatus probeStatus;

    public String status() {
        return "Monitor is up";
    }

    private RestReporter getReporter() {
        return null;
    }

    private ProbeStatus getLastEvent() {
        return null;
    }

    @Override
    protected long getLastModified(HttpServletRequest req) {
        updateProbeStatus();
        return probeStatus == null ? -1 : probeStatus.getTimestamp();
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        try {
            super.init(config);
            ctx = config.getServletContext();
            owner = (RestReporter) ctx.getAttribute(RestServer.OWNER);
        } catch (ServletException e) {
            throw e;
        } catch (Exception e) {
            throw new ServletException(e);
        }
    }

    private synchronized void updateProbeStatus() {
        probeStatus = owner.getLastEvent();
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        updateProbeStatus();
        if (probeStatus == null) {
            doGetNullProbeStatus(req, resp);
        } else {
            doGetProbeStatus(req, resp, probeStatus);
        }
    }

    private void doGetNullProbeStatus(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put(LIVE, false);
        writeJSON(resp, map, HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    }

    private void writeJSON(HttpServletResponse resp, HashMap<String, Object> map, int status) throws IOException {
        resp.setStatus(status);
        ObjectMapper json = new ObjectMapper();
        json.writeValue(resp.getOutputStream(), map);
    }

    private void doGetProbeStatus(HttpServletRequest req, HttpServletResponse resp, ProbeStatus status)
            throws ServletException, IOException {

        boolean live = status.isSuccess();
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put(LIVE, live);
        map.put("timestamp", status.getTimestamp());
        map.put("phase", status.getProbePhase());
        map.put("message", status.getMessage());
        Throwable thrown = status.getThrown();
        if (thrown != null) {
            HashMap<String, Object> tmap = new HashMap<String, Object>();
            tmap.put("message", thrown.toString());
            StackTraceElement[] stackTrace = thrown.getStackTrace();
            int index = 0;
            for (StackTraceElement elt : stackTrace) {
                tmap.put(Integer.toString(index++), elt.toString());
            }
            map.put("exception", tmap);
        }
        writeJSON(resp, map, HttpServletResponse.SC_OK);

    }

}