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聊聊dubbo的LogbackContainer

序

本文主要研究一下dubbo的LogbackContainer

LogbackContainer

dubbo-2.7.2/dubbo-container/dubbo-container-logback/src/main/java/org/apache/dubbo/container/logback/LogbackContainer.java

public class LogbackContainer implements Container {

    public static final String LOGBACK_FILE = "dubbo.logback.file";

    public static final String LOGBACK_LEVEL = "dubbo.logback.level";

    public static final String LOGBACK_MAX_HISTORY = "dubbo.logback.maxhistory";

    public static final String DEFAULT_LOGBACK_LEVEL = "ERROR";

    @Override
    public void start() {
        String file = ConfigUtils.getProperty(LOGBACK_FILE);
        if (file != null && file.length() > 0) {
            String level = ConfigUtils.getProperty(LOGBACK_LEVEL);
            if (StringUtils.isEmpty(level)) {
                level = DEFAULT_LOGBACK_LEVEL;
            }
            // maxHistory=0 Infinite history
            int maxHistory = StringUtils.parseInteger(ConfigUtils.getProperty(LOGBACK_MAX_HISTORY));

            doInitializer(file, level, maxHistory);
        }
    }

    @Override
    public void stop() {
    }

    /**
     * Initializer logback
     *
     * @param file
     * @param level
     * @param maxHistory
     */
    private void doInitializer(String file, String level, int maxHistory) {
        LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
        Logger rootLogger = loggerContext.getLogger(Logger.ROOT_LOGGER_NAME);
        rootLogger.detachAndStopAllAppenders();

        // appender
        RollingFileAppender<ILoggingEvent> fileAppender = new RollingFileAppender<ILoggingEvent>();
        fileAppender.setContext(loggerContext);
        fileAppender.setName("application");
        fileAppender.setFile(file);
        fileAppender.setAppend(true);

        // policy
        TimeBasedRollingPolicy<ILoggingEvent> policy = new TimeBasedRollingPolicy<ILoggingEvent>();
        policy.setContext(loggerContext);
        policy.setMaxHistory(maxHistory);
        policy.setFileNamePattern(file + ".%d{yyyy-MM-dd}");
        policy.setParent(fileAppender);
        policy.start();
        fileAppender.setRollingPolicy(policy);

        // encoder
        PatternLayoutEncoder encoder = new PatternLayoutEncoder();
        encoder.setContext(loggerContext);
        encoder.setPattern("%date [%thread] %-5level %logger (%file:%line//) - %msg%n");
        encoder.start();
        fileAppender.setEncoder(encoder);

        fileAppender.start();

        rootLogger.addAppender(fileAppender);
        rootLogger.setLevel(Level.toLevel(level));
        rootLogger.setAdditive(false);
    }

}

LogbackContainer实现了Container接口，其start方法判断是否有指定dubbo.logback.file，如果有则进一步获取dubbo.logback.level，如果为空则默认为ERROR级别，然后再获取dubbo.logback.maxhistory，最后调用doInitializer；doInitializer方法先获取rootLogger，然后执行detachAndStopAllAppenders，然后配置RollingFileAppender，并指定policy为TimeBasedRollingPolicy，并设置PatternLayoutEncoder，然后启动fileAppender，并添加到rootLogger中

实例

dubbo-2.7.2/dubbo-container/dubbo-container-logback/src/test/java/org/apache/dubbo/container/logback/LogbackContainerTest.java

public class LogbackContainerTest {

    private static final Logger logger = LoggerFactory.getLogger(LogbackContainerTest.class);

    @Test
    public void testContainer() {
        LogbackContainer container = (LogbackContainer) ExtensionLoader.getExtensionLoader(Container.class)
                .getExtension("logback");
        container.start();

        logger.debug("Test debug:" + this.getClass().getName());
        logger.warn("Test warn:" + this.getClass().getName());
        logger.info("Test info:" + this.getClass().getName());
        logger.error("Test error:" + this.getClass().getName());

        container.stop();
    }

}

这里通过启动logback的container然后再使用logger输出进行验证

小结

LogbackContainer实现了Container接口，其start方法判断是否有指定dubbo.logback.file，如果有则进一步获取dubbo.logback.level，如果为空则默认为ERROR级别，然后再获取dubbo.logback.maxhistory，最后调用doInitializer；doInitializer方法先获取rootLogger，然后执行detachAndStopAllAppenders，然后配置RollingFileAppender，并指定policy为TimeBasedRollingPolicy，并设置PatternLayoutEncoder，然后启动fileAppender，并添加到rootLogger中