org.apache.aurora.common.net.http.handlers.LogConfig.java Source code

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Here is the source code for org.apache.aurora.common.net.http.handlers.LogConfig.java

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/**
 * 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 org.apache.aurora.common.net.http.handlers;

import java.io.StringWriter;
import java.util.List;
import java.util.Optional;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.Logger;
import java.util.logging.LoggingMXBean;

import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import com.google.common.collect.Lists;
import com.google.common.collect.Ordering;

import org.antlr.stringtemplate.StringTemplate;
import org.apache.aurora.common.base.Closure;
import org.apache.aurora.common.util.templating.StringTemplateHelper;
import org.apache.aurora.common.util.templating.StringTemplateHelper.TemplateException;
import org.apache.commons.lang.StringUtils;

/**
 * Servlet that allows for dynamic adjustment of the logging configuration.
 *
 * @author William Farner
 */
@Path("/logconfig")
public class LogConfig {
    private static final List<String> LOG_LEVELS = Lists.newArrayList(Level.SEVERE.getName(),
            Level.WARNING.getName(), Level.INFO.getName(), Level.CONFIG.getName(), Level.FINE.getName(),
            Level.FINER.getName(), Level.FINEST.getName(), "INHERIT" // Display value for a null level, the logger inherits from its ancestor.
    );

    private final StringTemplateHelper template = new StringTemplateHelper(getClass(), "logconfig", false);

    @POST
    @Produces(MediaType.TEXT_HTML)
    public String post(@FormParam("logger") String loggerName, @FormParam("level") String loggerLevel)
            throws TemplateException {

        Optional<String> configChange = Optional.empty();
        if (loggerName != null && loggerLevel != null) {
            Logger logger = Logger.getLogger(loggerName);
            Level newLevel = loggerLevel.equals("INHERIT") ? null : Level.parse(loggerLevel);
            logger.setLevel(newLevel);
            if (newLevel != null) {
                maybeAdjustHandlerLevels(logger, newLevel);
            }

            configChange = Optional.of(String.format("%s level changed to %s", loggerName, loggerLevel));
        }

        return displayPage(configChange);
    }

    @GET
    @Produces(MediaType.TEXT_HTML)
    public String get() throws TemplateException {
        return displayPage(Optional.empty());
    }

    protected String displayPage(Optional<String> configChange) throws TemplateException {
        StringWriter writer = new StringWriter();

        template.writeTemplate(writer, new Closure<StringTemplate>() {
            @Override
            public void execute(StringTemplate stringTemplate) {
                LoggingMXBean logBean = LogManager.getLoggingMXBean();

                if (configChange.isPresent()) {
                    stringTemplate.setAttribute("configChange", configChange.get());
                }

                List<LoggerConfig> loggerConfigs = Lists.newArrayList();
                for (String logger : Ordering.natural().immutableSortedCopy(logBean.getLoggerNames())) {
                    loggerConfigs.add(new LoggerConfig(logger, logBean.getLoggerLevel(logger)));
                }

                stringTemplate.setAttribute("loggers", loggerConfigs);
                stringTemplate.setAttribute("levels", LOG_LEVELS);
            }
        });

        return writer.toString();
    }

    private void maybeAdjustHandlerLevels(Logger logger, Level newLevel) {
        do {
            for (Handler handler : logger.getHandlers()) {
                Level handlerLevel = handler.getLevel();
                if (newLevel.intValue() < handlerLevel.intValue()) {
                    handler.setLevel(newLevel);
                }
            }
        } while (logger.getUseParentHandlers() && (logger = logger.getParent()) != null);
    }

    private class LoggerConfig {
        private final String name;
        private final String level;

        public LoggerConfig(String name, String level) {
            this.name = name;
            this.level = StringUtils.isBlank(level) ? "INHERIT" : level;
        }

        public String getName() {
            return name;
        }

        public String getLevel() {
            return level;
        }
    }
}