Sync update and bump version to 0.1.1

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/AbstractDubboFilter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.adapter.dubbo;
 
 import com.alibaba.dubbo.rpc.Filter;

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/DubboAppContextFilter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.adapter.dubbo;
 
 import com.alibaba.dubbo.common.Constants;

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/DubboUtils.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.adapter.dubbo;
 
 import com.alibaba.dubbo.rpc.Invocation;

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/SentinelDubboConsumerFilter.java

@@ -1,12 +1,28 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.adapter.dubbo;
 
 import com.alibaba.csp.sentinel.Entry;
 import com.alibaba.csp.sentinel.EntryType;
 import com.alibaba.csp.sentinel.SphU;
 import com.alibaba.csp.sentinel.Tracer;
+import com.alibaba.csp.sentinel.adapter.dubbo.fallback.DubboFallbackRegistry;
 import com.alibaba.csp.sentinel.context.ContextUtil;
+import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.slots.block.BlockException;
-import com.alibaba.csp.sentinel.slots.block.SentinelRpcException;
 import com.alibaba.dubbo.common.extension.Activate;
 import com.alibaba.dubbo.rpc.Filter;
 import com.alibaba.dubbo.rpc.Invocation;
@@ -23,10 +39,15 @@
  * </pre>
  *
  * @author leyou
+ * @author Eric Zhao
  */
 @Activate(group = "consumer")
 public class SentinelDubboConsumerFilter extends AbstractDubboFilter implements Filter {
 
+    public SentinelDubboConsumerFilter() {
+        RecordLog.info("Sentinel Dubbo consumer filter initialized");
+    }
+
     @Override
     public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
         Entry interfaceEntry = null;
@@ -38,7 +59,7 @@ public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcExcept
             methodEntry = SphU.entry(resourceName, EntryType.OUT);
             return invoker.invoke(invocation);
         } catch (BlockException e) {
-            throw new SentinelRpcException(e);
+            return DubboFallbackRegistry.getConsumerFallback().handle(invoker, invocation, e);
         } catch (RpcException e) {
             Tracer.trace(e);
             throw e;

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/SentinelDubboProviderFilter.java

@@ -1,10 +1,27 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.adapter.dubbo;
 
 import com.alibaba.csp.sentinel.Entry;
 import com.alibaba.csp.sentinel.EntryType;
 import com.alibaba.csp.sentinel.SphU;
 import com.alibaba.csp.sentinel.Tracer;
+import com.alibaba.csp.sentinel.adapter.dubbo.fallback.DubboFallbackRegistry;
 import com.alibaba.csp.sentinel.context.ContextUtil;
+import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.slots.block.BlockException;
 import com.alibaba.csp.sentinel.slots.block.SentinelRpcException;
 import com.alibaba.dubbo.common.extension.Activate;
@@ -23,10 +40,15 @@
  * </pre>
  *
  * @author leyou
+ * @author Eric Zhao
  */
 @Activate(group = "provider")
 public class SentinelDubboProviderFilter extends AbstractDubboFilter implements Filter {
 
+    public SentinelDubboProviderFilter() {
+        RecordLog.info("Sentinel Dubbo provider filter initialized");
+    }
+
     @Override
     public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
         // Get origin caller.
@@ -43,7 +65,7 @@ public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcExcept
 
             return invoker.invoke(invocation);
         } catch (BlockException e) {
-            throw new SentinelRpcException(e);
+            return DubboFallbackRegistry.getProviderFallback().handle(invoker, invocation, e);
         } catch (RpcException e) {
             Tracer.trace(e);
             throw e;

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/fallback/DefaultDubboFallback.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.adapter.dubbo.fallback;
+
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.csp.sentinel.slots.block.SentinelRpcException;
+import com.alibaba.dubbo.rpc.Invocation;
+import com.alibaba.dubbo.rpc.Invoker;
+import com.alibaba.dubbo.rpc.Result;
+
+/**
+ * @author Eric Zhao
+ */
+public class DefaultDubboFallback implements DubboFallback {
+
+    @Override
+    public Result handle(Invoker<?> invoker, Invocation invocation, BlockException ex) {
+        // Just wrap and throw the exception.
+        throw new SentinelRpcException(ex);
+    }
+}

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/fallback/DubboFallback.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.adapter.dubbo.fallback;
+
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.dubbo.rpc.Invocation;
+import com.alibaba.dubbo.rpc.Invoker;
+import com.alibaba.dubbo.rpc.Result;
+
+/**
+ * Fallback handler for Dubbo services.
+ *
+ * @author Eric Zhao
+ */
+public interface DubboFallback {
+
+    /**
+     * Handle the block exception and provide fallback result.
+     *
+     * @param invoker Dubbo invoker
+     * @param invocation Dubbo invocation
+     * @param ex block exception
+     * @return fallback result
+     */
+    Result handle(Invoker<?> invoker, Invocation invocation, BlockException ex);
+}

src/main/java/com/alibaba/csp/sentinel/adapter/dubbo/fallback/DubboFallbackRegistry.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.adapter.dubbo.fallback;
+
+/**
+ * Global fallback registry for Dubbo.
+ *
+ * Note: Degrading is mainly designed for consumer. The provider should not
+ * give fallback result in most circumstances.
+ *
+ * @author Eric Zhao
+ */
+public final class DubboFallbackRegistry {
+
+    private static volatile DubboFallback consumerFallback = new DefaultDubboFallback();
+    private static volatile DubboFallback providerFallback = new DefaultDubboFallback();
+
+    public static DubboFallback getConsumerFallback() {
+        return consumerFallback;
+    }
+
+    public static void setConsumerFallback(DubboFallback consumerFallback) {
+        DubboFallbackRegistry.consumerFallback = consumerFallback;
+    }
+
+    public static DubboFallback getProviderFallback() {
+        return providerFallback;
+    }
+
+    public static void setProviderFallback(DubboFallback providerFallback) {
+        DubboFallbackRegistry.providerFallback = providerFallback;
+    }
+
+    private DubboFallbackRegistry() {}
+}