Add HTTP-method level flow control support in Sentinel Web Servlet Filter (#282)

- Add HTTP method level support for servlet filter with a init parameter `HTTP_METHOD_SPECIFY` as the switch. This is useful for REST APIs.
- Add test cases and fix test bug by reset the cluster node in ClusterBuilderSlot

sentinel-adapter/sentinel-web-servlet/src/main/java/com/alibaba/csp/sentinel/adapter/servlet/CommonFilter.java

@@ -46,17 +46,23 @@ import com.alibaba.csp.sentinel.util.StringUtil;
  */
 public class CommonFilter implements Filter {
 
+    private final static String HTTP_METHOD_SPECIFY = "HTTP_METHOD_SPECIFY";
+    private final static String COLON = ":";
+    private boolean httpMethodSpecify = false;
+
     @Override
     public void init(FilterConfig filterConfig) {
-
+        httpMethodSpecify = Boolean.parseBoolean(filterConfig.getInitParameter(HTTP_METHOD_SPECIFY));
     }
 
     @Override
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
-        throws IOException, ServletException {
-        HttpServletRequest sRequest = (HttpServletRequest)request;
+            throws IOException, ServletException {
+        HttpServletRequest sRequest = (HttpServletRequest) request;
         Entry entry = null;
 
+        Entry methodEntry = null;
+
         try {
             String target = FilterUtil.filterTarget(sRequest);
             // Clean and unify the URL.
@@ -73,9 +79,16 @@ public class CommonFilter implements Filter {
             ContextUtil.enter(target, origin);
             entry = SphU.entry(target, EntryType.IN);
 
+
+            // Add method specification if necessary
+            if (httpMethodSpecify) {
+                methodEntry = SphU.entry(sRequest.getMethod().toUpperCase() + COLON + target,
+                        EntryType.IN);
+            }
+
             chain.doFilter(request, response);
         } catch (BlockException e) {
-            HttpServletResponse sResponse = (HttpServletResponse)response;
+            HttpServletResponse sResponse = (HttpServletResponse) response;
             // Return the block page, or redirect to another URL.
             WebCallbackManager.getUrlBlockHandler().blocked(sRequest, sResponse, e);
         } catch (IOException e2) {
@@ -88,6 +101,9 @@ public class CommonFilter implements Filter {
             Tracer.trace(e4);
             throw e4;
         } finally {
+            if (methodEntry != null) {
+                methodEntry.exit();
+            }
             if (entry != null) {
                 entry.exit();
             }

sentinel-adapter/sentinel-web-servlet/src/test/java/com/alibaba/csp/sentinel/adapter/servlet/CommonFilterTest.java

@@ -171,6 +171,6 @@ public class CommonFilterTest {
     @After
     public void cleanUp() {
         FlowRuleManager.loadRules(null);
-        ClusterBuilderSlot.getClusterNodeMap().clear();
+        ClusterBuilderSlot.resetClusterNodes();
     }
 }

sentinel-adapter/sentinel-web-servlet/src/test/java/com/alibaba/csp/sentinel/adapter/servletmethod/CommonFilterMethodTest.java

@@ -0,0 +1,133 @@
+/*
+ * 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.servletmethod;
+
+import com.alibaba.csp.sentinel.adapter.servlet.config.WebServletConfig;
+import com.alibaba.csp.sentinel.adapter.servlet.util.FilterUtil;
+import com.alibaba.csp.sentinel.node.ClusterNode;
+import com.alibaba.csp.sentinel.slots.block.RuleConstant;
+import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
+import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
+import com.alibaba.csp.sentinel.slots.clusterbuilder.ClusterBuilderSlot;
+import com.alibaba.csp.sentinel.util.StringUtil;
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+import java.util.Collections;
+
+import static org.junit.Assert.*;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+/**
+ * @author Roger Law
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = TestApplication.class,
+        webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@AutoConfigureMockMvc
+public class CommonFilterMethodTest {
+
+    private static final String HELLO_STR = "Hello!";
+
+    private static final String HELLO_POST_STR = "Hello Post!";
+
+    private static final String GET = "GET";
+
+    private static final String POST = "POST";
+
+    private static final String COLON = ":";
+
+    @Autowired
+    private MockMvc mvc;
+
+    private void configureRulesFor(String resource, int count) {
+        configureRulesFor(resource, count, "default");
+    }
+
+    private void configureRulesFor(String resource, int count, String limitApp) {
+        FlowRule rule = new FlowRule()
+                .setCount(count)
+                .setGrade(RuleConstant.FLOW_GRADE_QPS);
+        rule.setResource(resource);
+        if (StringUtil.isNotBlank(limitApp)) {
+            rule.setLimitApp(limitApp);
+        }
+        FlowRuleManager.loadRules(Collections.singletonList(rule));
+    }
+
+    @Test
+    public void testCommonFilterMiscellaneous() throws Exception {
+        String url = "/hello";
+        this.mvc.perform(get(url))
+                .andExpect(status().isOk())
+                .andExpect(content().string(HELLO_STR));
+
+        ClusterNode cnGet = ClusterBuilderSlot.getClusterNode(GET + COLON + url);
+        assertNotNull(cnGet);
+        assertEquals(1, cnGet.passQps());
+
+
+        ClusterNode cnPost = ClusterBuilderSlot.getClusterNode(POST + COLON + url);
+        assertNull(cnPost);
+
+        this.mvc.perform(post(url))
+                .andExpect(status().isOk())
+                .andExpect(content().string(HELLO_POST_STR));
+
+        cnPost = ClusterBuilderSlot.getClusterNode(POST + COLON + url);
+        assertNotNull(cnPost);
+        assertEquals(1, cnPost.passQps());
+
+        testCommonBlockAndRedirectBlockPage(url, cnGet, cnPost);
+
+    }
+
+    private void testCommonBlockAndRedirectBlockPage(String url, ClusterNode cnGet, ClusterNode cnPost) throws Exception {
+        configureRulesFor(GET + ":" + url, 0);
+        // The request will be blocked and response is default block message.
+        this.mvc.perform(get(url).accept(MediaType.TEXT_PLAIN))
+                .andExpect(status().isOk())
+                .andExpect(content().string(FilterUtil.DEFAULT_BLOCK_MSG));
+        assertEquals(1, cnGet.blockQps());
+
+        // Test for post pass
+        this.mvc.perform(post(url))
+                .andExpect(status().isOk())
+                .andExpect(content().string(HELLO_POST_STR));
+
+        assertEquals(2, cnPost.passQps());
+
+
+        FlowRuleManager.loadRules(null);
+        WebServletConfig.setBlockPage("");
+    }
+
+
+    @After
+    public void cleanUp() {
+        FlowRuleManager.loadRules(null);
+        ClusterBuilderSlot.resetClusterNodes();
+    }
+}

sentinel-adapter/sentinel-web-servlet/src/test/java/com/alibaba/csp/sentinel/adapter/servletmethod/FilterMethodConfig.java

@@ -0,0 +1,25 @@
+package com.alibaba.csp.sentinel.adapter.servletmethod;
+
+import com.alibaba.csp.sentinel.adapter.servlet.CommonFilter;
+import org.springframework.boot.web.servlet.FilterRegistrationBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author: Roger Law
+ **/
+@Configuration
+public class FilterMethodConfig {
+
+    @Bean
+    public FilterRegistrationBean sentinelFilterRegistration() {
+        FilterRegistrationBean registration = new FilterRegistrationBean();
+        registration.setFilter(new CommonFilter());
+        registration.addUrlPatterns("/*");
+        registration.addInitParameter("HTTP_METHOD_SPECIFY", "true");
+        registration.setName("sentinelFilter");
+        registration.setOrder(1);
+
+        return registration;
+    }
+}

sentinel-adapter/sentinel-web-servlet/src/test/java/com/alibaba/csp/sentinel/adapter/servletmethod/TestApplication.java

@@ -0,0 +1,30 @@
+/*
+ * 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.servletmethod;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author Eric Zhao
+ */
+@SpringBootApplication
+public class TestApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(TestApplication.class, args);
+    }
+}

sentinel-adapter/sentinel-web-servlet/src/test/java/com/alibaba/csp/sentinel/adapter/servletmethod/TestMethodController.java

@@ -0,0 +1,38 @@
+/*
+ * 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.servletmethod;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * @author Roger Law
+ */
+@RestController
+public class TestMethodController {
+
+    @GetMapping("/hello")
+    public String apiHello() {
+        return "Hello!";
+    }
+
+    @PostMapping("/hello")
+    public String apiHelloPost() {
+        return "Hello Post!";
+    }
+
+}