Talk about dubbo’s SpringContainer.

  dubbo

Order

This article mainly studies dubbo’s SpringContainer

Container

dubbo-2.7.2/dubbo-container/dubbo-container-api/src/main/java/org/apache/dubbo/container/Container.java

@SPI("spring")
public interface Container {

    /**
     * start method to load the container.
     */
    void start();

    /**
     * stop method to unload the container.
     */
    void stop();

}
  • The Container interface defines the start and stop methods.

SpringContainer

dubbo-2.7.2/dubbo-container/dubbo-container-spring/src/main/java/org/apache/dubbo/container/spring/SpringContainer.java

public class SpringContainer implements Container {

    public static final String SPRING_CONFIG = "dubbo.spring.config";
    public static final String DEFAULT_SPRING_CONFIG = "classpath*:META-INF/spring/*.xml";
    private static final Logger logger = LoggerFactory.getLogger(SpringContainer.class);
    static ClassPathXmlApplicationContext context;

    public static ClassPathXmlApplicationContext getContext() {
        return context;
    }

    @Override
    public void start() {
        String configPath = ConfigUtils.getProperty(SPRING_CONFIG);
        if (StringUtils.isEmpty(configPath)) {
            configPath = DEFAULT_SPRING_CONFIG;
        }
        context = new ClassPathXmlApplicationContext(configPath.split("[,\\s]+"), false);
        context.refresh();
        context.start();
    }

    @Override
    public void stop() {
        try {
            if (context != null) {
                context.stop();
                context.close();
                context = null;
            }
        } catch (Throwable e) {
            logger.error(e.getMessage(), e);
        }
    }

}
  • SpringContainer implements the Container interface, and its start method creates ClassPathXmlApplicationContext, and then executes refresh and start methods. Its stop method executes the stop and close methods of ClassPathXmlApplicationContext.

Main

dubbo-2.7.2/dubbo-container/dubbo-container-api/src/main/java/org/apache/dubbo/container/Main.java

public class Main {

    public static final String CONTAINER_KEY = "dubbo.container";

    public static final String SHUTDOWN_HOOK_KEY = "dubbo.shutdown.hook";

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

    private static final ExtensionLoader<Container> loader = ExtensionLoader.getExtensionLoader(Container.class);

    private static final ReentrantLock LOCK = new ReentrantLock();

    private static final Condition STOP = LOCK.newCondition();

    public static void main(String[] args) {
        try {
            if (ArrayUtils.isEmpty(args)) {
                String config = ConfigUtils.getProperty(CONTAINER_KEY, loader.getDefaultExtensionName());
                args = COMMA_SPLIT_PATTERN.split(config);
            }

            final List<Container> containers = new ArrayList<Container>();
            for (int i = 0; i < args.length; i++) {
                containers.add(loader.getExtension(args[i]));
            }
            logger.info("Use container type(" + Arrays.toString(args) + ") to run dubbo serivce.");

            if ("true".equals(System.getProperty(SHUTDOWN_HOOK_KEY))) {
                Runtime.getRuntime().addShutdownHook(new Thread("dubbo-container-shutdown-hook") {
                    @Override
                    public void run() {
                        for (Container container : containers) {
                            try {
                                container.stop();
                                logger.info("Dubbo " + container.getClass().getSimpleName() + " stopped!");
                            } catch (Throwable t) {
                                logger.error(t.getMessage(), t);
                            }
                            try {
                                LOCK.lock();
                                STOP.signal();
                            } finally {
                                LOCK.unlock();
                            }
                        }
                    }
                });
            }

            for (Container container : containers) {
                container.start();
                logger.info("Dubbo " + container.getClass().getSimpleName() + " started!");
            }
            System.out.println(new SimpleDateFormat("[yyyy-MM-dd HH:mm:ss]").format(new Date()) + " Dubbo service server started!");
        } catch (RuntimeException e) {
            logger.error(e.getMessage(), e);
            System.exit(1);
        }
        try {
            LOCK.lock();
            STOP.await();
        } catch (InterruptedException e) {
            logger.warn("Dubbo service server stopped, interrupted by other thread!", e);
        } finally {
            LOCK.unlock();
        }
    }

}
  • The main method of Main first loads the configured containers, and then executes the start method one by one. If shutdownHook is configured, register dubo-container-shutdown-hook and call the container’s stop method one by one.

Summary

SpringContainer implements the Container interface, and its start method creates ClassPathXmlApplicationContext, and then executes refresh and start methods. Its stop method executes the stop and close methods of ClassPathXmlApplicationContext.

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