001/*
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v2.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.classic.model.processor;
015
016import ch.qos.logback.classic.joran.ReconfigureOnChangeTask;
017import ch.qos.logback.classic.model.ConfigurationModel;
018import ch.qos.logback.core.Context;
019import ch.qos.logback.core.CoreConstants;
020import ch.qos.logback.core.joran.spi.ConfigurationWatchList;
021import ch.qos.logback.core.joran.util.ConfigurationWatchListUtil;
022import ch.qos.logback.core.model.Model;
023import ch.qos.logback.core.model.processor.ModelHandlerBase;
024import ch.qos.logback.core.model.processor.ModelHandlerException;
025import ch.qos.logback.core.model.processor.ModelInterpretationContext;
026import ch.qos.logback.core.spi.ConfigurationEvent;
027import ch.qos.logback.core.util.Duration;
028import ch.qos.logback.core.util.OptionHelper;
029
030import java.util.concurrent.ScheduledExecutorService;
031import java.util.concurrent.ScheduledFuture;
032import java.util.concurrent.TimeUnit;
033
034/**
035 * This is a subclass of {@link ConfigurationModelHandler} offering configuration reloading support.
036 *
037 * <p>This class is also called by logback-tyler.</p>
038 *
039 */
040public class ConfigurationModelHandlerFull extends ConfigurationModelHandler {
041
042    public static final String FAILED_WATCH_PREDICATE_MESSAGE_1 = "Missing watchable .xml or .properties files.";
043    public static final String FAILED_WATCH_PREDICATE_MESSAGE_2 = "Watching .xml files requires that the main configuration file is reachable as a URL";
044
045    public ConfigurationModelHandlerFull(Context context) {
046        super(context);
047    }
048
049    static public ModelHandlerBase makeInstance(Context context, ModelInterpretationContext mic) {
050        return new ConfigurationModelHandlerFull(context);
051    }
052
053    @Override
054    public void postHandle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
055        ConfigurationModel configurationModel = (ConfigurationModel) model;
056
057        // scanning is disabled
058        if (scanning != Boolean.TRUE) {
059            return;
060        }
061
062        String scanPeriodStr = mic.subst(configurationModel.getScanPeriodStr());
063        scheduleReconfigureOnChangeTask(scanPeriodStr);
064
065        ConfigurationWatchList cwl = ConfigurationWatchListUtil.getConfigurationWatchList(getContext());
066        if (cwl != null) {
067            try {
068                addInfo("Main configuration file URL: " + cwl.getTopURL());
069                addInfo("FileWatchList= {" + cwl.getFileWatchListAsStr() + "}");
070                addInfo("URLWatchList= {" + cwl.getUrlWatchListAsStr() + "}");
071            } catch (NoSuchMethodError e) {
072                addWarn("It looks like the version of logback-classic is more recent than");
073                addWarn("the version of logback-core. Please align the two versions.");
074            }
075        }
076    }
077
078
079    /**
080     * This method is called from logback-tyler version 1.0.4 and earlier.
081     * <p>
082     * This method assumes that the variables scanStr and scanPeriodStr have undergone variable substitution
083     * as applicable to their current environment
084     *
085     * @param scanPeriodStr
086     * @since 1.5.0
087     */
088    public void detachedPostProcess(String scanStr, String scanPeriodStr) {
089        if (OptionHelper.isNullOrEmptyOrAllSpaces(scanStr) || CoreConstants.FALSE_STR.equalsIgnoreCase(scanStr)) {
090            return;
091        }
092
093        scheduleReconfigureOnChangeTask(scanPeriodStr);
094    }
095
096    /**
097     * This method is called from logback-tyler version 1.0.x and later.
098     * <p>
099     * This method assumes that the variables scanPeriodStr has undergone variable substitution
100     * as applicable to their current environment
101     *
102     * @param scanPeriodStr
103     * @since 1.5.28
104     */
105    public void detachedPostProcess(String scanPeriodStr) {
106        scheduleReconfigureOnChangeTask(scanPeriodStr);
107    }
108
109
110    /**
111     * Schedules a task to monitor configuration changes and reconfigure the application when changes are detected.
112     * The task periodically scans for changes based on the given scan period and reconfigures the system if needed.
113     * This method ensures a valid configuration watch is in place before scheduling the task.
114     *
115     * @param scanPeriodStr the string value representing the scanning period, which will determine how often
116     *                      the task checks for configuration changes. The value is expected to have undergone
117     *                      necessary variable substitution for the current environment.
118     */
119    private void scheduleReconfigureOnChangeTask(String scanPeriodStr) {
120
121        boolean watchPredicateFulfilled = ConfigurationWatchListUtil.watchPredicateFulfilled(context);
122        if (!watchPredicateFulfilled) {
123            addWarn(FAILED_WATCH_PREDICATE_MESSAGE_1);
124            addWarn(FAILED_WATCH_PREDICATE_MESSAGE_2);
125            return;
126        }
127
128        ReconfigureOnChangeTask rocTask = new ReconfigureOnChangeTask();
129        rocTask.setContext(context);
130
131        addInfo("Registering a new ReconfigureOnChangeTask " + rocTask);
132
133        context.fireConfigurationEvent(ConfigurationEvent.newConfigurationChangeDetectorRegisteredEvent(rocTask));
134
135        Duration duration = getDurationOfScanPeriodAttribute(scanPeriodStr, SCAN_PERIOD_DEFAULT);
136
137        ConfigurationWatchList cwl = ConfigurationWatchListUtil.getConfigurationWatchList(context);
138
139        String fileWatchListAsStr = (cwl != null) ? cwl.getFileWatchListAsStr() : "";
140
141        addInfo("Will scan for changes in [" + fileWatchListAsStr + "] ");
142        // Given that included files are encountered at a later phase, the complete list
143        // of files to scan can only be determined when the configuration is loaded in full.
144        // However, scan can be active if mainURL is set. Otherwise, when changes are
145        // detected the top level config file cannot be accessed.
146        addInfo("Setting ReconfigureOnChangeTask scanning period to " + duration);
147
148        ScheduledExecutorService scheduledExecutorService = context.getScheduledExecutorService();
149        ScheduledFuture<?> scheduledFuture = scheduledExecutorService.scheduleAtFixedRate(rocTask, duration.getMilliseconds(), duration.getMilliseconds(),
150                TimeUnit.MILLISECONDS);
151        rocTask.setScheduledFuture(scheduledFuture);
152        context.addScheduledFuture(scheduledFuture);
153
154    }
155
156    private Duration getDurationOfScanPeriodAttribute(String scanPeriodAttrib, Duration defaultDuration) {
157        Duration duration = null;
158
159        if (!OptionHelper.isNullOrEmptyOrAllSpaces(scanPeriodAttrib)) {
160            try {
161                duration = Duration.valueOf(scanPeriodAttrib);
162            } catch (IllegalStateException | IllegalArgumentException e) {
163                addWarn("Failed to parse 'scanPeriod' attribute [" + scanPeriodAttrib + "]", e);
164                // default duration will be set below
165            }
166        }
167
168        if (duration == null) {
169            addInfo("No 'scanPeriod' specified. Defaulting to " + defaultDuration.toString());
170            duration = defaultDuration;
171        }
172        return duration;
173    }
174}