Optimize shutdown hook

dorado/dorado-core/src/main/java/com/meituan/dorado/config/service/AbstractConfig.java

@@ -19,7 +19,7 @@
 import com.meituan.dorado.trace.TraceFactory;
 import com.meituan.dorado.util.ClazzUtil;
 
-public abstract class AbstractConfig {
+public abstract class AbstractConfig implements Disposable {
 
     protected String serviceName;
     // 服务接口, 调用端必配, 服务端若没有配置则取实现类的第一个接口

dorado/dorado-core/src/main/java/com/meituan/dorado/config/service/Disposable.java

@@ -0,0 +1,6 @@
+package com.meituan.dorado.config.service;
+
+public interface Disposable {
+
+    void destroy();
+}

dorado/dorado-core/src/main/java/com/meituan/dorado/config/service/ProviderConfig.java

@@ -29,7 +29,7 @@
 import java.util.List;
 import java.util.concurrent.BlockingQueue;
 
-public class ProviderConfig {
+public class ProviderConfig implements Disposable {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(ProviderConfig.class);
 
@@ -66,8 +66,6 @@ public class ProviderConfig {
     private List<Filter> filters = Collections.emptyList();
     private String env = Constants.EnvType.TEST.getEnvName();
 
-    private volatile ShutDownHook hook;
-
     private volatile boolean destroyed;
 
     public void init() {
@@ -104,10 +102,7 @@ public synchronized void destroy() {
     }
 
     protected synchronized void addShutDownHook() {
-        if (hook == null) {
-            hook = new ShutDownHook(this);
-            Runtime.getRuntime().addShutdownHook(hook);
-        }
+        ShutdownHook.register(this);
     }
 
     public List<String> getServiceList() {
@@ -250,17 +245,4 @@ public void setThreadPoolQueue(BlockingQueue<Runnable> threadPoolQueue) {
         this.threadPoolQueue = threadPoolQueue;
     }
 
-    class ShutDownHook extends Thread {
-        private ProviderConfig config;
-
-        public ShutDownHook(ProviderConfig config) {
-            this.config = config;
-        }
-
-        @Override
-        public void run() {
-            hook = null;
-            config.destroy();
-        }
-    }
 }

dorado/dorado-core/src/main/java/com/meituan/dorado/config/service/ReferenceConfig.java

@@ -35,7 +35,7 @@
 import java.util.List;
 import java.util.Map;
 
-public class ReferenceConfig<T> extends AbstractConfig {
+public class ReferenceConfig<T> extends AbstractConfig implements Disposable {
 
     // 必配项 服务端 appkey
     private String remoteAppkey;
@@ -84,8 +84,6 @@ public class ReferenceConfig<T> extends AbstractConfig {
     private transient ClusterHandler<?> clusterHandler;
 
     private volatile boolean destroyed;
-    private volatile ShutDownHook hook;
-
 
     public synchronized T get() {
         if (destroyed) {
@@ -141,10 +139,7 @@ private void configRouter() {
     }
 
     protected synchronized void addShutDownHook() {
-        if (hook == null) {
-            hook = new ShutDownHook(this);
-            Runtime.getRuntime().addShutdownHook(hook);
-        }
+        ShutdownHook.register(this);
     }
 
     /**
@@ -345,17 +340,4 @@ public void setEnv(String env) {
         this.env = env;
     }
 
-    class ShutDownHook extends Thread {
-        private ReferenceConfig config;
-
-        public ShutDownHook(ReferenceConfig config) {
-            this.config = config;
-        }
-
-        @Override
-        public void run() {
-            hook = null;
-            config.destroy();
-        }
-    }
 }

dorado/dorado-core/src/main/java/com/meituan/dorado/config/service/ShutdownHook.java

@@ -0,0 +1,27 @@
+package com.meituan.dorado.config.service;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class ShutdownHook extends Thread {
+
+    private static final List<Disposable> configs = new LinkedList<>();
+
+    static {
+        Runtime.getRuntime().addShutdownHook(new ShutdownHook());
+    }
+
+    public static synchronized void register(Disposable config) {
+        configs.add(config);
+    }
+
+    private ShutdownHook() {
+        super("DoradoShutdownHook-Thread");
+    }
+    @Override
+    public void run() {
+        for (Disposable config : configs) {
+            config.destroy();
+        }
+    }
+}

dorado/dorado-doc/manual-user/ShutdownGracefully.md

@@ -5,23 +5,29 @@ Dorado的优雅关闭通过ShutDownHook方式实现，调用端和服务端通
 
 ```java
 protected synchronized void addShutDownHook() {
-    if (hook == null) {
-        hook = new ShutDownHook(this);
-        Runtime.getRuntime().addShutdownHook(hook);
-    }
+    ShutdownHook.register(this);
 }
 
-class ShutDownHook extends Thread {
-    private ReferenceConfig config;
-
-    public ShutDownHook(ReferenceConfig config) {
-        this.config = config;
+public class ShutdownHook extends Thread {
+
+    private static final List<Disposable> configs = new LinkedList<>();
+
+    static {
+        Runtime.getRuntime().addShutdownHook(new ShutdownHook());
+    }
+
+    public static synchronized void register(Disposable config) {
+        configs.add(config);
+    }
+
+    private ShutdownHook() {
+        super("DoradoShutdownHook-Thread");
     }
-
     @Override
     public void run() {
-        hook = null;
-        config.destroy(); 
+        for (Disposable config : configs) {
+            config.destroy();
+        }
     }
 }
 ```