org.cryptomator.ui.logging.ConfigurableFileAppender.java Source code

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Here is the source code for org.cryptomator.ui.logging.ConfigurableFileAppender.java

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/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * This file is licensed under the terms of the MIT license.
 * See the LICENSE.txt file for more info.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.ui.logging;

import java.io.IOException;
import java.io.Serializable;
import java.net.URISyntaxException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.regex.Pattern;

import org.apache.commons.lang3.SystemUtils;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender;
import org.apache.logging.log4j.core.appender.FileManager;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.layout.PatternLayout;
import org.apache.logging.log4j.core.util.Booleans;
import org.apache.logging.log4j.util.Strings;

/**
 * A preconfigured FileAppender only relying on a configurable system property, e.g. <code>-Dcryptomator.logPath=/var/log/cryptomator.log</code>.<br/>
 * Other than the normal {@link org.apache.logging.log4j.core.appender.FileAppender} paths can be resolved relative to the users home directory.
 */
@Plugin(name = "ConfigurableFile", category = "Core", elementType = "appender", printObject = true)
public class ConfigurableFileAppender extends AbstractOutputStreamAppender<FileManager> {

    private static final long serialVersionUID = -6548221568069606389L;
    private static final int DEFAULT_BUFFER_SIZE = 8192;
    private static final Pattern DRIVE_LETTER_WITH_PRECEEDING_SLASH = Pattern.compile("^/[A-Z]:",
            Pattern.CASE_INSENSITIVE);

    protected ConfigurableFileAppender(String name, Layout<? extends Serializable> layout, Filter filter,
            FileManager manager) {
        super(name, layout, filter, true, true, manager);
        LOGGER.info("Logging to " + manager.getFileName());
    }

    @PluginFactory
    public static AbstractAppender createAppender(@PluginAttribute("name") final String name,
            @PluginAttribute("pathPropertyName") final String pathPropertyName,
            @PluginAttribute("append") final String append,
            @PluginElement("Layout") Layout<? extends Serializable> layout) {
        if (name == null) {
            LOGGER.error("No name provided for HomeDirectoryAwareFileAppender");
            return null;
        }

        if (pathPropertyName == null) {
            LOGGER.error("No pathPropertyName provided for HomeDirectoryAwareFileAppender with name " + name);
            return null;
        }

        final String fileName = System.getProperty(pathPropertyName);
        if (Strings.isEmpty(fileName)) {
            LOGGER.warn("No log file location provided in system property \"" + pathPropertyName + "\"");
            return null;
        }

        final Path filePath = parsePath(fileName);
        if (filePath == null) {
            LOGGER.warn("Invalid path \"" + fileName + "\"");
            return null;
        }

        if (!Files.exists(filePath.getParent())) {
            try {
                Files.createDirectories(filePath.getParent());
            } catch (IOException e) {
                LOGGER.error("Could not create parent directories for log file located at " + filePath.toString(),
                        e);
                return null;
            }
        }

        final boolean shouldAppend = Booleans.parseBoolean(append, true);
        if (layout == null) {
            layout = PatternLayout.createDefaultLayout();
        }

        final FileManager manager = FileManager.getFileManager(filePath.toString(), shouldAppend, false, true, null,
                layout, DEFAULT_BUFFER_SIZE);
        return new ConfigurableFileAppender(name, layout, null, manager);
    }

    private static Path parsePath(String path) {
        if (path.startsWith("~/")) {
            // home-dir-relative Path:
            final Path userHome = FileSystems.getDefault().getPath(SystemUtils.USER_HOME);
            return userHome.resolve(path.substring(2));
        } else if (path.startsWith("/")) {
            // absolute Path:
            return FileSystems.getDefault().getPath(path);
        } else {
            // relative Path:
            try {
                String jarFileLocation = ConfigurableFileAppender.class.getProtectionDomain().getCodeSource()
                        .getLocation().toURI().getPath();
                if (SystemUtils.IS_OS_WINDOWS
                        && DRIVE_LETTER_WITH_PRECEEDING_SLASH.matcher(jarFileLocation).find()) {
                    // on windows we need to remove a preceeding slash from "/C:/foo/bar":
                    jarFileLocation = jarFileLocation.substring(1);
                }
                final Path workingDir = FileSystems.getDefault().getPath(jarFileLocation).getParent();
                return workingDir.resolve(path);
            } catch (URISyntaxException e) {
                LOGGER.error("Unable to resolve working directory ", e);
                return null;
            }
        }
    }

}