Add compatible adapter module for Apache Dubbo 2.7.x and above

sentinel-adapter/pom.xml

@@ -17,6 +17,7 @@
     <modules>
         <module>sentinel-web-servlet</module>
         <module>sentinel-dubbo-adapter</module>
+        <module>sentinel-apache-dubbo-adapter</module>
         <module>sentinel-grpc-adapter</module>
         <module>sentinel-zuul-adapter</module>
         <module>sentinel-reactor-adapter</module>

sentinel-adapter/sentinel-apache-dubbo-adapter/README.md

@@ -0,0 +1,68 @@
+# Sentinel Apache Dubbo Adapter
+
+> Note: 中文文档请见[此处](https://github.com/alibaba/Sentinel/wiki/主流框架的适配#dubbo)。
+
+Sentinel Dubbo Adapter provides service consumer filter and provider filter
+for [Apache Dubbo](https://dubbo.apache.org/en-us/) services.
+
+**Note: This adapter only supports Apache Dubbo 2.7.x and above.** For legacy `com.alibaba:dubbo` 2.6.x,
+please use `sentinel-dubbo-adapter` module instead.
+
+To use Sentinel Dubbo Adapter, you can simply add the following dependency to your `pom.xml`:
+
+```xml
+<dependency>
+    <groupId>com.alibaba.csp</groupId>
+    <artifactId>sentinel-apache-dubbo-adapter</artifactId>
+    <version>x.y.z</version>
+</dependency>
+```
+
+The Sentinel filters are **enabled by default**. Once you add the dependency,
+the Dubbo services and methods will become protected resources in Sentinel,
+which can leverage Sentinel's flow control and guard ability when rules are configured.
+Demos can be found in [sentinel-demo-dubbo](https://github.com/alibaba/Sentinel/tree/master/sentinel-demo/sentinel-demo-dubbo).
+
+If you don't want the filters enabled, you can manually disable them. For example:
+
+```xml
+<dubbo:consumer filter="-sentinel.dubbo.consumer.filter"/>
+
+<dubbo:provider filter="-sentinel.dubbo.provider.filter"/>
+```
+
+For more details of Dubbo filter, see [here](http://dubbo.apache.org/en-us/docs/dev/impls/filter.html).
+
+## Dubbo resources
+
+The resource for Dubbo services has two granularities: service interface and service method.
+
+- Service interface：resourceName format is `interfaceName`，e.g. `com.alibaba.csp.sentinel.demo.dubbo.FooService`
+- Service method：resourceName format is `interfaceName:methodSignature`，e.g. `com.alibaba.csp.sentinel.demo.dubbo.FooService:sayHello(java.lang.String)`
+
+## Flow control based on caller
+
+In many circumstances, it's also significant to control traffic flow based on the **caller**.
+For example, assuming that there are two services A and B, both of them initiate remote call requests to the service provider.
+If we want to limit the calls from service B only, we can set the `limitApp` of flow rule as the identifier of service B (e.g. service name).
+
+Sentinel Dubbo Adapter will automatically resolve the Dubbo consumer's *application name* as the caller's name (`origin`),
+and will bring the caller's name when doing resource protection.
+If `limitApp` of flow rules is not configured (`default`), flow control will take effects on all callers.
+If `limitApp` of a flow rule is configured with a caller, then the corresponding flow rule will only take effect on the specific caller.
+
+> Note: Dubbo consumer does not provide its Dubbo application name when doing RPC,
+so developers should manually put the application name into *attachment* at consumer side,
+then extract it at provider side. Sentinel Dubbo Adapter has implemented a filter (`DubboAppContextFilter`)
+where consumer can carry application name information to provider automatically.
+If the consumer does not use Sentinel Dubbo Adapter but requires flow control based on caller, developers can manually put the application name into attachment with the key `dubboApplication`.
+
+## Global fallback
+
+Sentinel Dubbo Adapter supports global fallback configuration.
+The global fallback will handle exceptions and give replacement result when blocked by
+flow control, degrade or system load protection. You can implement your own `DubboFallback` interface
+and then register to `DubboFallbackRegistry`. If no fallback is configured, Sentinel will wrap the `BlockException`
+then directly throw it out.
+
+Besides, we can also leverage [Dubbo mock mechanism](http://dubbo.apache.org/en-us/docs/user/demos/local-mock.html) to provide fallback implementation of degraded Dubbo services.

sentinel-adapter/sentinel-apache-dubbo-adapter/pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>sentinel-adapter</artifactId>
+        <groupId>com.alibaba.csp</groupId>
+        <version>1.5.1-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>sentinel-apache-dubbo-adapter</artifactId>
+    <packaging>jar</packaging>
+
+    <properties>
+        <java.source.version>1.8</java.source.version>
+        <java.target.version>1.8</java.target.version>
+        <apache.dubbo.version>2.7.1</apache.dubbo.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.dubbo</groupId>
+            <artifactId>dubbo</artifactId>
+            <version>${apache.dubbo.version}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>fastjson</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

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

@@ -0,0 +1,43 @@
+/*
+ * 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 org.apache.dubbo.common.Constants;
+import org.apache.dubbo.common.extension.Activate;
+import org.apache.dubbo.rpc.Filter;
+import org.apache.dubbo.rpc.Invocation;
+import org.apache.dubbo.rpc.Invoker;
+import org.apache.dubbo.rpc.Result;
+import org.apache.dubbo.rpc.RpcContext;
+import org.apache.dubbo.rpc.RpcException;
+
+/**
+ * Puts current consumer's application name in the attachment of each invocation.
+ *
+ * @author Eric Zhao
+ */
+@Activate(group = "consumer")
+public class DubboAppContextFilter implements Filter {
+
+    @Override
+    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
+        String application = invoker.getUrl().getParameter(Constants.APPLICATION_KEY);
+        if (application != null) {
+            RpcContext.getContext().setAttachment(DubboUtils.SENTINEL_DUBBO_APPLICATION_KEY, application);
+        }
+        return invoker.invoke(invocation);
+    }
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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 org.apache.dubbo.rpc.Invocation;
+import org.apache.dubbo.rpc.Invoker;
+
+/**
+ * @author Eric Zhao
+ */
+public final class DubboUtils {
+
+    public static final String SENTINEL_DUBBO_APPLICATION_KEY = "dubboApplication";
+
+    public static String getApplication(Invocation invocation, String defaultValue) {
+        if (invocation == null || invocation.getAttachments() == null) {
+            throw new IllegalArgumentException("Bad invocation instance");
+        }
+        return invocation.getAttachment(SENTINEL_DUBBO_APPLICATION_KEY, defaultValue);
+    }
+
+    public static String getResourceName(Invoker<?> invoker, Invocation invocation) {
+        StringBuilder buf = new StringBuilder(64);
+        buf.append(invoker.getInterface().getName())
+            .append(":")
+            .append(invocation.getMethodName())
+            .append("(");
+        boolean isFirst = true;
+        for (Class<?> clazz : invocation.getParameterTypes()) {
+            if (!isFirst) {
+                buf.append(",");
+            }
+            buf.append(clazz.getName());
+            isFirst = false;
+        }
+        buf.append(")");
+        return buf.toString();
+    }
+
+    private DubboUtils() {}
+}

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

@@ -0,0 +1,83 @@
+/*
+ * 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.log.RecordLog;
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+
+import com.alibaba.csp.sentinel.adapter.dubbo.fallback.DubboFallbackRegistry;
+import org.apache.dubbo.common.extension.Activate;
+import org.apache.dubbo.rpc.Filter;
+import org.apache.dubbo.rpc.Invocation;
+import org.apache.dubbo.rpc.Invoker;
+import org.apache.dubbo.rpc.Result;
+import org.apache.dubbo.rpc.RpcException;
+
+/**
+ * <p>Dubbo service consumer filter for Sentinel. Auto activated by default.</p>
+ *
+ * If you want to disable the consumer filter, you can configure:
+ * <pre>
+ * &lt;dubbo:consumer filter="-sentinel.dubbo.consumer.filter"/&gt;
+ * </pre>
+ *
+ * @author Carpenter Lee
+ * @author Eric Zhao
+ */
+@Activate(group = "consumer")
+public class SentinelDubboConsumerFilter implements Filter {
+
+    public SentinelDubboConsumerFilter() {
+        RecordLog.info("Sentinel Apache Dubbo consumer filter initialized");
+    }
+
+    @Override
+    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
+        Entry interfaceEntry = null;
+        Entry methodEntry = null;
+        try {
+            String resourceName = DubboUtils.getResourceName(invoker, invocation);
+            interfaceEntry = SphU.entry(invoker.getInterface().getName(), EntryType.OUT);
+            methodEntry = SphU.entry(resourceName, EntryType.OUT);
+
+            Result result = invoker.invoke(invocation);
+            if (result.hasException()) {
+                Throwable e = result.getException();
+                // Record common exception.
+                Tracer.traceEntry(e, interfaceEntry);
+                Tracer.traceEntry(e, methodEntry);
+            }
+            return result;
+        } catch (BlockException e) {
+            return DubboFallbackRegistry.getConsumerFallback().handle(invoker, invocation, e);
+        } catch (RpcException e) {
+            Tracer.traceEntry(e, interfaceEntry);
+            Tracer.traceEntry(e, methodEntry);
+            throw e;
+        } finally {
+            if (methodEntry != null) {
+                methodEntry.exit();
+            }
+            if (interfaceEntry != null) {
+                interfaceEntry.exit();
+            }
+        }
+    }
+}