Adapter: Support Apache HttpClient (#1455)

Introduce support through a customized client builder `SentinelApacheHttpClientBuilder`.

sentinel-adapter/pom.xml

@@ -18,6 +18,7 @@
         <module>sentinel-web-servlet</module>
         <module>sentinel-dubbo-adapter</module>
         <module>sentinel-apache-dubbo-adapter</module>
+        <module>sentinel-apache-httpclient-adapter</module>
         <module>sentinel-sofa-rpc-adapter</module>
         <module>sentinel-grpc-adapter</module>
         <module>sentinel-zuul-adapter</module>

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

@@ -0,0 +1,75 @@
+# Sentinel Apache Httpclient Adapter
+
+## Introduction
+
+Sentinel provides integration for OkHttp client to enable flow control for web requests.
+
+Add the following dependency in `pom.xml` (if you are using Maven):
+
+```xml
+<dependency>
+    <groupId>com.alibaba.csp</groupId>
+    <artifactId>sentinel-apache-httpclient-adapter</artifactId>
+    <version>x.y.z</version>
+</dependency>
+```
+
+We can use the `SentinelApacheHttpClientBuilder` when `CloseableHttpClient` at initialization, for example:
+
+```java
+CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder().build();
+```
+
+If we want to add some additional configurations, we can refer to the following code
+
+```java
+HttpClientBuilder builder = new SentinelApacheHttpClientBuilder();
+//builder Other Definitions
+CloseableHttpClient httpclient = builder.build();
+```
+
+## Configuration
+
+- `SentinelApacheHttpClientConfig` configuration:
+
+| name | description | type | default value |
+|------|------------|------|-------|
+| prefix | customize resource prefix | `String` | `httpclient:` |
+| extractor | customize resource extractor | `ApacheHttpClientResourceExtractor` | `DefaultApacheHttpClientResourceExtractor` |
+| fallback | handle request when it is blocked | `ApacheHttpClientFallback` | `DefaultApacheHttpClientFallback` |
+
+### extractor (resource extractor)
+
+We can define `ApacheHttpClientResourceExtractor` to customize resource extractor replace `DefaultApacheHttpClientResourceExtractor` at `SentinelApacheHttpClientBuilder` default config, for example: httpclient:GET:/httpclient/back/1 ==> httpclient:GET:/httpclient/back/{id}
+
+```java
+SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+config.setExtractor(new ApacheHttpClientResourceExtractor() {
+
+    @Override
+    public String extractor(HttpRequestWrapper request) {
+        String contains = "/httpclient/back/";
+        String uri = request.getRequestLine().getUri();
+        if (uri.startsWith(contains)) {
+            uri = uri.substring(0, uri.indexOf(contains) + contains.length()) + "{id}";
+        }
+        return request.getMethod() + ":" + uri;
+    }
+});
+CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder(config).build();
+```
+
+### fallback (Block handling)
+
+We can define `ApacheHttpClientFallback` at `SentinelApacheHttpClientBuilder` default config, to handle request is blocked according to the actual scenario, for example:
+
+```java
+public class DefaultApacheHttpClientFallback implements ApacheHttpClientFallback {
+
+    @Override
+    public CloseableHttpResponse handle(HttpRequestWrapper request, BlockException e) {
+        // Just wrap and throw the exception.
+        throw new SentinelRpcException(e);
+    }
+}
+```

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

@@ -0,0 +1,69 @@
+<?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>1.8.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>sentinel-apache-httpclient-adapter</artifactId>
+    <packaging>jar</packaging>
+
+    <properties>
+        <apache.httpclient.version>4.5.6</apache.httpclient.version>
+        <spring.boot.version>2.1.3.RELEASE</spring.boot.version>
+        <spring-test.version>5.1.5.RELEASE</spring-test.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${apache.httpclient.version}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>fastjson</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+            <version>${spring.boot.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-test</artifactId>
+            <version>${spring.boot.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>${spring-test.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/SentinelApacheHttpClientBuilder.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient;
+
+import com.alibaba.csp.sentinel.*;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.config.SentinelApacheHttpClientConfig;
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.csp.sentinel.util.StringUtil;
+import org.apache.http.HttpException;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpExecutionAware;
+import org.apache.http.client.methods.HttpRequestWrapper;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.conn.routing.HttpRoute;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.execchain.ClientExecChain;
+
+import java.io.IOException;
+
+/**
+ * @author zhaoyuguang
+ */
+public class SentinelApacheHttpClientBuilder extends HttpClientBuilder {
+
+    private final SentinelApacheHttpClientConfig config;
+
+    public SentinelApacheHttpClientBuilder(){
+        this.config = new SentinelApacheHttpClientConfig();
+    }
+
+    public SentinelApacheHttpClientBuilder(SentinelApacheHttpClientConfig config){
+        this.config = config;
+    }
+
+    @Override
+    protected ClientExecChain decorateMainExec(final ClientExecChain mainExec) {
+        return new ClientExecChain() {
+            @Override
+            public CloseableHttpResponse execute(HttpRoute route, HttpRequestWrapper request,
+                                                 HttpClientContext clientContext, HttpExecutionAware execAware)
+                    throws IOException, HttpException {
+                Entry entry = null;
+                try {
+                    String name = config.getExtractor().extractor(request);
+                    if (!StringUtil.isEmpty(config.getPrefix())) {
+                        name = config.getPrefix() + name;
+                    }
+                    entry = SphU.entry(name, ResourceTypeConstants.COMMON_WEB, EntryType.OUT);
+                    return mainExec.execute(route, request, clientContext, execAware);
+                } catch (BlockException e) {
+                    return config.getFallback().handle(request, e);
+                } catch (Throwable t) {
+                    Tracer.traceEntry(t, entry);
+                    throw t;
+                } finally {
+                    if (entry != null) {
+                        entry.exit();
+                    }
+                }
+            }
+        };
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/config/SentinelApacheHttpClientConfig.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.config;
+
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.extractor.ApacheHttpClientResourceExtractor;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.extractor.DefaultApacheHttpClientResourceExtractor;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.fallback.ApacheHttpClientFallback;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.fallback.DefaultApacheHttpClientFallback;
+import com.alibaba.csp.sentinel.util.AssertUtil;
+
+/**
+ * @author zhaoyuguang
+ */
+public class SentinelApacheHttpClientConfig {
+
+    private String prefix = "httpclient:";
+    private ApacheHttpClientResourceExtractor extractor = new DefaultApacheHttpClientResourceExtractor();
+    private ApacheHttpClientFallback fallback = new DefaultApacheHttpClientFallback();
+
+    public String getPrefix() {
+        return prefix;
+    }
+
+    public void setPrefix(String prefix) {
+        AssertUtil.notNull(prefix, "prefix cannot be null");
+        this.prefix = prefix;
+    }
+
+    public ApacheHttpClientResourceExtractor getExtractor() {
+        return extractor;
+    }
+
+    public void setExtractor(ApacheHttpClientResourceExtractor extractor) {
+        AssertUtil.notNull(extractor, "extractor cannot be null");
+        this.extractor = extractor;
+    }
+
+    public ApacheHttpClientFallback getFallback() {
+        return fallback;
+    }
+
+    public void setFallback(ApacheHttpClientFallback fallback) {
+        AssertUtil.notNull(fallback, "fallback cannot be null");
+        this.fallback = fallback;
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/extractor/ApacheHttpClientResourceExtractor.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.extractor;
+
+import org.apache.http.client.methods.HttpRequestWrapper;
+
+/**
+ * @author zhaoyuguang
+ */
+public interface ApacheHttpClientResourceExtractor {
+
+    String extractor(HttpRequestWrapper request);
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/extractor/DefaultApacheHttpClientResourceExtractor.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.extractor;
+
+import org.apache.http.client.methods.HttpRequestWrapper;
+
+/**
+ * @author zhaoyuguang
+ */
+public class DefaultApacheHttpClientResourceExtractor implements ApacheHttpClientResourceExtractor {
+
+    @Override
+    public String extractor(HttpRequestWrapper request) {
+        return request.getRequestLine().getUri();
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/fallback/ApacheHttpClientFallback.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.fallback;
+
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import org.apache.http.HttpException;
+import org.apache.http.HttpRequest;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpRequestWrapper;
+import org.apache.http.protocol.HttpContext;
+
+import java.io.IOException;
+
+/**
+ * @author zhaoyuguang
+ */
+public interface ApacheHttpClientFallback {
+
+    CloseableHttpResponse handle(HttpRequestWrapper request, BlockException e);
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/fallback/DefaultApacheHttpClientFallback.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.fallback;
+
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.csp.sentinel.slots.block.SentinelRpcException;
+import org.apache.http.HttpException;
+import org.apache.http.HttpRequest;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpRequestWrapper;
+import org.apache.http.protocol.HttpContext;
+
+import java.io.IOException;
+
+/**
+ * @author zhaoyuguang
+ */
+public class DefaultApacheHttpClientFallback implements ApacheHttpClientFallback {
+
+    @Override
+    public CloseableHttpResponse handle(HttpRequestWrapper request, BlockException e) {
+        // Just wrap and throw the exception.
+        throw new SentinelRpcException(e);
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/SentinelApacheHttpClientTest.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient;
+
+import com.alibaba.csp.sentinel.Constants;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.app.TestApplication;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.config.SentinelApacheHttpClientConfig;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.extractor.ApacheHttpClientResourceExtractor;
+import com.alibaba.csp.sentinel.node.ClusterNode;
+import com.alibaba.csp.sentinel.slots.clusterbuilder.ClusterBuilderSlot;
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpRequestWrapper;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.protocol.BasicHttpContext;
+import org.apache.http.protocol.HttpContext;
+import org.apache.http.util.EntityUtils;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * @author zhaoyuguang
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = TestApplication.class,
+        webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT,
+        properties = {
+                "server.port=8084"
+        })
+public class SentinelApacheHttpClientTest {
+
+    @Value("${server.port}")
+    private Integer port;
+
+    @Test
+    public void testSentinelOkHttpInterceptor0() throws Exception {
+
+        CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder().build();
+
+        HttpGet httpGet = new HttpGet("http://localhost:" + port + "/httpclient/back");
+        System.out.println(getRemoteString(httpclient, httpGet));
+        ClusterNode cn = ClusterBuilderSlot.getClusterNode("httpclient:/httpclient/back");
+        assertNotNull(cn);
+        Constants.ROOT.removeChildList();
+        ClusterBuilderSlot.getClusterNodeMap().clear();
+    }
+
+    @Test
+    public void testSentinelOkHttpInterceptor1() throws Exception {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setExtractor(new ApacheHttpClientResourceExtractor() {
+
+            @Override
+            public String extractor(HttpRequestWrapper request) {
+                String contains = "/httpclient/back/";
+                String uri = request.getRequestLine().getUri();
+                if (uri.startsWith(contains)) {
+                    uri = uri.substring(0, uri.indexOf(contains) + contains.length()) + "{id}";
+                }
+                return request.getMethod() + ":" + uri;
+            }
+        });
+        CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder(config).build();
+
+        HttpGet httpGet = new HttpGet("http://localhost:" + port + "/httpclient/back/1");
+        System.out.println(getRemoteString(httpclient, httpGet));
+        ClusterNode cn = ClusterBuilderSlot.getClusterNode("httpclient:GET:/httpclient/back/{id}");
+        assertNotNull(cn);
+        Constants.ROOT.removeChildList();
+        ClusterBuilderSlot.getClusterNodeMap().clear();
+    }
+
+    private String getRemoteString(CloseableHttpClient httpclient, HttpGet httpGet) throws IOException {
+        String result;
+        HttpContext context = new BasicHttpContext();
+        CloseableHttpResponse response;
+        response = httpclient.execute(httpGet, context);
+        try {
+            HttpEntity entity = response.getEntity();
+            result = EntityUtils.toString(entity, "utf-8");
+            EntityUtils.consume(entity);
+        } finally {
+            response.close();
+        }
+        httpclient.close();
+        return result;
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/app/TestApplication.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.app;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author zhaoyuguang
+ */
+@SpringBootApplication
+public class TestApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(TestApplication.class);
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/app/controller/TestController.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.app.controller;
+
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * @author zhaoyuguang
+ */
+@RestController
+public class TestController {
+
+    @RequestMapping("/httpclient/back")
+    public String back() {
+        return "Welcome Back!";
+    }
+
+    @RequestMapping("/httpclient/back/{id}")
+    public String back(@PathVariable String id) {
+        return "Welcome Back! " + id;
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/config/SentinelApacheHttpClientConfigTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.config;
+
+import org.junit.Test;
+
+/**
+ * @author zhaoyuguang
+ */
+public class SentinelApacheHttpClientConfigTest {
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testConfigSetPrefix() {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setPrefix(null);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testConfigSetCleaner() {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setExtractor(null);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testConfigSetFallback() {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setFallback(null);
+    }
+}

sentinel-adapter/sentinel-apache-httpclient-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/apache/httpclient/fallback/ApacheHttpClientFallbackTest.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 1999-2020 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.apache.httpclient.fallback;
+
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.csp.sentinel.slots.block.SentinelRpcException;
+import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
+import org.junit.Test;
+
+/**
+ * @author zhaoyuguang
+ */
+public class ApacheHttpClientFallbackTest {
+
+    @Test(expected = SentinelRpcException.class)
+    public void testDefaultOkHttpFallback() {
+        BlockException e = new FlowException("xxx");
+        ApacheHttpClientFallback fallback = new DefaultApacheHttpClientFallback();
+        fallback.handle(null, e);
+    }
+}

sentinel-demo/pom.xml

@@ -32,6 +32,7 @@
         <module>sentinel-demo-command-handler</module>
         <module>sentinel-demo-spring-webflux</module>
         <module>sentinel-demo-apache-dubbo</module>
+        <module>sentinel-demo-apache-httpclient</module>
         <module>sentinel-demo-sofa-rpc</module>
         <module>sentinel-demo-spring-cloud-gateway</module>
         <module>sentinel-demo-zuul-gateway</module>

sentinel-demo/sentinel-demo-apache-httpclient/pom.xml

@@ -0,0 +1,52 @@
+<?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-demo</artifactId>
+        <groupId>com.alibaba.csp</groupId>
+        <version>1.8.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>sentinel-demo-apache-httpclient</artifactId>
+
+    <properties>
+        <spring.boot.version>2.1.3.RELEASE</spring.boot.version>
+        <test.framework.version>4.3</test.framework.version>
+        <apache.httpclient.version>4.5.6</apache.httpclient.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-transport-simple-http</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-apache-httpclient-adapter</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+            <version>${spring.boot.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <version>${spring.boot.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${apache.httpclient.version}</version>
+        </dependency>
+    </dependencies>
+
+</project>

sentinel-demo/sentinel-demo-apache-httpclient/src/main/java/com/alibaba/csp/sentinel/demo/apache/httpclient/ApacheHttpClientDemoApplication.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 1999-2020 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.demo.apache.httpclient;
+
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author zhaoyuguang
+ */
+@SpringBootApplication
+public class ApacheHttpClientDemoApplication implements CommandLineRunner {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ApacheHttpClientDemoApplication.class);
+    }
+
+    @Override
+    public void run(String... args) {
+    }
+}

sentinel-demo/sentinel-demo-apache-httpclient/src/main/java/com/alibaba/csp/sentinel/demo/apache/httpclient/controller/ApacheHttpClientTestController.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright 1999-2020 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.demo.apache.httpclient.controller;
+
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.SentinelApacheHttpClientBuilder;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.config.SentinelApacheHttpClientConfig;
+import com.alibaba.csp.sentinel.adapter.apache.httpclient.extractor.ApacheHttpClientResourceExtractor;
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpRequestWrapper;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.protocol.BasicHttpContext;
+import org.apache.http.protocol.HttpContext;
+import org.apache.http.util.EntityUtils;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.io.IOException;
+
+/**
+ * @author zhaoyuguang
+ */
+@RestController
+public class ApacheHttpClientTestController {
+
+    @Value("${server.port}")
+    private Integer port;
+
+    @RequestMapping("/httpclient/back")
+    public String back() {
+        System.out.println("back");
+        return "Welcome Back!";
+    }
+
+    @RequestMapping("/httpclient/back/{id}")
+    public String back(@PathVariable String id) {
+        System.out.println("back");
+        return "Welcome Back! " + id;
+    }
+
+    @RequestMapping("/httpclient/sync")
+    public String sync() throws Exception {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setExtractor(new ApacheHttpClientResourceExtractor() {
+
+            @Override
+            public String extractor(HttpRequestWrapper request) {
+                String contains = "/httpclient/back/";
+                String uri = request.getRequestLine().getUri();
+                if (uri.startsWith(contains)) {
+                    uri = uri.substring(0, uri.indexOf(contains) + contains.length()) + "{id}";
+                }
+                return request.getMethod() + ":" + uri;
+            }
+        });
+        CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder(config).build();
+
+        HttpGet httpGet = new HttpGet("http://localhost:" + port + "/httpclient/back");
+        return getRemoteString(httpclient, httpGet);
+    }
+
+    @RequestMapping("/httpclient/sync/{id}")
+    public String sync(@PathVariable String id) throws Exception {
+        SentinelApacheHttpClientConfig config = new SentinelApacheHttpClientConfig();
+        config.setExtractor(new ApacheHttpClientResourceExtractor() {
+
+            @Override
+            public String extractor(HttpRequestWrapper request) {
+                String contains = "/httpclient/back/";
+                String uri = request.getRequestLine().getUri();
+                if (uri.startsWith(contains)) {
+                    uri = uri.substring(0, uri.indexOf(contains) + contains.length()) + "{id}";
+                }
+                return request.getMethod() + ":" + uri;
+            }
+        });
+        CloseableHttpClient httpclient = new SentinelApacheHttpClientBuilder(config).build();
+
+        HttpGet httpGet = new HttpGet("http://localhost:" + port + "/httpclient/back/" + id);
+        return getRemoteString(httpclient, httpGet);
+    }
+
+    private String getRemoteString(CloseableHttpClient httpclient, HttpGet httpGet) throws IOException {
+        String result;
+        HttpContext context = new BasicHttpContext();
+        CloseableHttpResponse response;
+        response = httpclient.execute(httpGet, context);
+        try {
+            HttpEntity entity = response.getEntity();
+            result = EntityUtils.toString(entity, "utf-8");
+            EntityUtils.consume(entity);
+        } finally {
+            response.close();
+        }
+        httpclient.close();
+        return result;
+    }
+}

sentinel-demo/sentinel-demo-apache-httpclient/src/main/resources/application.properties

@@ -0,0 +1,2 @@
+spring.application.name=sentinel-demo-apache-httpclient
+server.port=8083