org.apache.sentry.provider.db.service.thrift.LogLevelServlet.java Source code

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Here is the source code for org.apache.sentry.provider.db.service.thrift.LogLevelServlet.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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.sentry.provider.db.service.thrift;

import org.apache.log4j.Level;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

import static org.apache.commons.lang.StringEscapeUtils.escapeHtml;

public class LogLevelServlet extends HttpServlet {
    private static final String LF = "\n";
    private static final String BR = "<br />";
    private static final String B_BR = "<b>%s</b><br />";
    private static final String FORMS_HEAD = "<h1>" + "Log Level" + "</h1>" + LF + BR + "<hr /><h3>Results</h3>"
            + LF + " Submitted Log Name: " + B_BR;
    private static final String FORMS_CONTENT_GET = LF + " Effective level: " + B_BR;
    private static final String FORMS_CONTENT_SET = LF + " Submitted Level: " + B_BR + LF + " Setting Level to %s"
            + BR + LF + " Effective level: " + B_BR;
    private static final String FORMS_END = LF + BR + "<hr /><h3>Get / Set</h3>" + LF
            + "<form>Log: <input type='text' size='50' name='log' /> "
            + "<input type='submit' value='Get Log Level' />" + "</form>" + LF
            + "<form>Log: <input type='text' size='50' name='log' /> "
            + "Level: <input type='text' name='level' /> " + "<input type='submit' value='Set Log Level' />"
            + "</form>";
    private static final String FORMS_GET = FORMS_HEAD + FORMS_CONTENT_GET;
    private static final String FORMS_SET = FORMS_HEAD + FORMS_CONTENT_SET;

    /**
     * Return parameter on servlet request for the given name
     *
     * @param request: Servlet request
     * @param name: Name of parameter in servlet request
     * @return Parameter in servlet request for the given name, return null if can't find parameter.
     */
    private String getParameter(ServletRequest request, String name) {
        String s = request.getParameter(name);
        if (s == null) {
            return null;
        }
        s = s.trim();
        return s.length() == 0 ? null : s;
    }

    /**
     * Check the validity of the log level.
     * @param level: The log level to be checked
     * @return
     *        true: The log level is valid
     *        false: The log level is invalid
     */
    private boolean isLogLevelValid(String level) {
        return level.equals(Level.toLevel(level).toString());
    }

    /**
     * Parse the class name and log level in the http servlet request.
     * If the request contains only class name, return the log level in the response message.
     * If the request contains both class name and level, set the log level to the requested level
     * and return the setting result in the response message.
     */
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String logName = getParameter(request, "log");
        String level = getParameter(request, "level");
        response.setContentType("text/html;charset=utf-8");
        response.setStatus(HttpServletResponse.SC_OK);
        PrintWriter out = response.getWriter();

        if (logName != null) {
            Logger logInstance = LogManager.getLogger(logName);
            if (level == null) {
                out.write(
                        String.format(FORMS_GET, escapeHtml(logName), logInstance.getEffectiveLevel().toString()));
            } else if (isLogLevelValid(level)) {
                logInstance.setLevel(Level.toLevel(level));
                out.write(String.format(FORMS_SET, escapeHtml(logName), level, level,
                        logInstance.getEffectiveLevel().toString()));
            } else {
                response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid log level: " + level);
                return;
            }
        }
        out.write(FORMS_END);
        out.close();
        response.flushBuffer();
    }
}