feat: sentinel can feel exception though application has configured ExceptionHandler (#3409)

Author: 24kpure

sentinel-adapter/sentinel-spring-webmvc-adapter/README.md

@@ -28,6 +28,12 @@ public class InterceptorConfig implements WebMvcConfigurer {
         // Add to the interceptor list.
         registry.addInterceptor(new SentinelWebInterceptor(config)).addPathPatterns("/**");
     }
+
+    @Bean
+    public SentinelExceptionAware sentinelExceptionAware(){
+        //Make exception visible to Sentinel if you have configured ExceptionHandler
+        return new SentinelExceptionAware();
+    }
 }
 ```
 

sentinel-adapter/sentinel-spring-webmvc-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/AbstractSentinelInterceptor.java

@@ -15,9 +15,6 @@
  */
 package com.alibaba.csp.sentinel.adapter.spring.webmvc;
 
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
 import com.alibaba.csp.sentinel.Entry;
 import com.alibaba.csp.sentinel.EntryType;
 import com.alibaba.csp.sentinel.ResourceTypeConstants;
@@ -29,14 +26,19 @@
 import com.alibaba.csp.sentinel.slots.block.BlockException;
 import com.alibaba.csp.sentinel.util.AssertUtil;
 import com.alibaba.csp.sentinel.util.StringUtil;
-
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletRequestAttributes;
 import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.ModelAndView;
 
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.util.Objects;
+
 /**
  * Since request may be reprocessed in flow if any forwarding or including or other action
- * happened (see {@link javax.servlet.ServletRequest#getDispatcherType()}) we will only 
- * deal with the initial request. So we use <b>reference count</b> to track in 
+ * happened (see {@link javax.servlet.ServletRequest#getDispatcherType()}) we will only
+ * deal with the initial request. So we use <b>reference count</b> to track in
  * dispathing "onion" though which we could figure out whether we are in initial type "REQUEST".
  * That means the sub-requests which we rarely meet in practice will NOT be recorded in Sentinel.
  * <p>
@@ -71,15 +73,15 @@ public AbstractSentinelInterceptor(BaseWebMvcConfig config) {
      * @param step
      * @return reference count after increasing (initial value as zero to be increased) 
      */
-    private Integer increaseReferece(HttpServletRequest request, String rcKey, int step) {
+    private Integer increaseReference(HttpServletRequest request, String rcKey, int step) {
         Object obj = request.getAttribute(rcKey);
-        
+
         if (obj == null) {
             // initial
-            obj = Integer.valueOf(0);
+            obj = 0;
         }
-        
-        Integer newRc = (Integer)obj + step;
+
+        Integer newRc = (Integer) obj + step;
         request.setAttribute(rcKey, newRc);
         return newRc;
     }
@@ -93,8 +95,8 @@ public boolean preHandle(HttpServletRequest request, HttpServletResponse respons
             if (StringUtil.isEmpty(resourceName)) {
                 return true;
             }
-            
-            if (increaseReferece(request, this.baseWebMvcConfig.getRequestRefName(), 1) != 1) {
+
+            if (increaseReference(request, this.baseWebMvcConfig.getRequestRefName(), 1) != 1) {
                 return true;
             }
 
@@ -136,7 +138,7 @@ protected String getContextName(HttpServletRequest request) {
     @Override
     public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
                                 Object handler, Exception ex) throws Exception {
-        if (increaseReferece(request, this.baseWebMvcConfig.getRequestRefName(), -1) != 0) {
+        if (increaseReference(request, this.baseWebMvcConfig.getRequestRefName(), -1) != 0) {
             return;
         }
 
@@ -168,12 +170,21 @@ protected void removeEntryInRequest(HttpServletRequest request) {
     }
 
     protected void traceExceptionAndExit(Entry entry, Exception ex) {
-        if (entry != null) {
-            if (ex != null) {
-                Tracer.traceEntry(ex, entry);
-            }
-            entry.exit();
+        if (entry == null) {
+            return;
         }
+        HttpServletRequest request = getHttpServletRequest();
+        if (request != null
+                && ex == null
+                && increaseReference(request, this.baseWebMvcConfig.getRequestRefName() + ":" + BaseWebMvcConfig.REQUEST_REF_EXCEPTION_NAME, 1) == 1) {
+            //Each interceptor can only catch exception once
+            ex = (Exception) request.getAttribute(BaseWebMvcConfig.REQUEST_REF_EXCEPTION_NAME);
+        }
+
+        if (ex != null) {
+            Tracer.traceEntry(ex, entry);
+        }
+        entry.exit();
     }
 
     protected void handleBlockException(HttpServletRequest request, HttpServletResponse response, BlockException e)
@@ -197,4 +208,9 @@ protected String parseOrigin(HttpServletRequest request) {
         return origin;
     }
 
+    private HttpServletRequest getHttpServletRequest() {
+        ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
+
+        return Objects.isNull(servletRequestAttributes) ? null : servletRequestAttributes.getRequest();
+    }
 }

sentinel-adapter/sentinel-spring-webmvc-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/SentinelExceptionAware.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 1999-2019 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
+ *
+ *      https://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.spring.webmvc;
+
+import com.alibaba.csp.sentinel.adapter.spring.webmvc.config.BaseWebMvcConfig;
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import org.springframework.core.annotation.Order;
+import org.springframework.web.servlet.HandlerExceptionResolver;
+import org.springframework.web.servlet.ModelAndView;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Make exception visible to Sentinel.SentinelExceptionAware should be front of ExceptionHandlerExceptionResolver
+ * whose order is 0 {@link  org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport#handlerExceptionResolver}
+ *
+ * @author lemonJ
+ */
+@Order(-1)
+public class SentinelExceptionAware implements HandlerExceptionResolver {
+    @Override
+    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
+        addExceptionToRequest(request, ex);
+        return null;
+    }
+
+    private void addExceptionToRequest(HttpServletRequest httpServletRequest, Exception exception) {
+        if(BlockException.isBlockException(exception)){
+            return;
+        }
+        httpServletRequest.setAttribute(BaseWebMvcConfig.REQUEST_REF_EXCEPTION_NAME, exception);
+    }
+}

sentinel-adapter/sentinel-spring-webmvc-adapter/src/main/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/config/BaseWebMvcConfig.java

@@ -26,6 +26,8 @@
  */
 public abstract class BaseWebMvcConfig {
 
+    public final static String REQUEST_REF_EXCEPTION_NAME = "$$sentinel_spring_web_entry_attr-exception";
+
     protected String requestAttributeName;
     protected String requestRefName;
     protected BlockExceptionHandler blockExceptionHandler;

sentinel-adapter/sentinel-spring-webmvc-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/SentinelSpringMvcIntegrationTest.java

@@ -23,6 +23,8 @@
 
 import com.alibaba.csp.sentinel.node.ClusterNode;
 import com.alibaba.csp.sentinel.slots.block.RuleConstant;
+import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
+import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
 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;
@@ -128,6 +130,32 @@ public void testRuntimeException() throws Exception {
         assertEquals(1, cn.blockRequest(), 1);
     }
 
+
+    @Test
+    public void testExceptionPerception() throws Exception {
+        String url = "/bizException";
+        configureExceptionDegradeRulesFor(url, 2.6, null);
+        int repeat = 3;
+        for (int i = 0; i < repeat; i++) {
+            this.mvc.perform(get(url))
+                    .andExpect(status().isOk())
+                    .andExpect(content().string(new ResultWrapper(-1, "Biz error").toJsonString()));
+
+            ClusterNode cn = ClusterBuilderSlot.getClusterNode(url);
+            assertNotNull(cn);
+            assertEquals(i + 1, cn.passQps(), 0.01);
+        }
+
+        // This will be blocked and response json.
+        this.mvc.perform(get(url))
+                .andExpect(status().isOk())
+                .andExpect(content().string(ResultWrapper.blocked().toJsonString()));
+        ClusterNode cn = ClusterBuilderSlot.getClusterNode(url);
+        assertNotNull(cn);
+        assertEquals(repeat, cn.passQps(), 0.01);
+        assertEquals(1, cn.blockRequest(), 1);
+    }
+
     private void configureRulesFor(String resource, int count, String limitApp) {
         FlowRule rule = new FlowRule()
                 .setCount(count)
@@ -150,6 +178,20 @@ private void configureExceptionRulesFor(String resource, int count, String limit
         FlowRuleManager.loadRules(Collections.singletonList(rule));
     }
 
+    private void configureExceptionDegradeRulesFor(String resource, double count, String limitApp) {
+        DegradeRule rule = new DegradeRule()
+                .setCount(count)
+                .setStatIntervalMs(1000)
+                .setMinRequestAmount(1)
+                .setTimeWindow(5)
+                .setGrade(RuleConstant.DEGRADE_GRADE_EXCEPTION_COUNT);
+        rule.setResource(resource);
+        if (StringUtil.isNotBlank(limitApp)) {
+            rule.setLimitApp(limitApp);
+        }
+        DegradeRuleManager.loadRules(Collections.singletonList(rule));
+    }
+
     @After
     public void cleanUp() {
         FlowRuleManager.loadRules(null);

sentinel-adapter/sentinel-spring-webmvc-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/config/InterceptorConfig.java

@@ -15,17 +15,16 @@
  */
 package com.alibaba.csp.sentinel.adapter.spring.webmvc.config;
 
+import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelExceptionAware;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelWebInterceptor;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelWebTotalInterceptor;
-import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.RequestOriginParser;
-import com.alibaba.csp.sentinel.slots.block.BlockException;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
 import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
 
 /**
  * Config sentinel interceptor
@@ -35,6 +34,11 @@
 @Configuration
 public class InterceptorConfig implements WebMvcConfigurer {
 
+    @Bean
+    public SentinelExceptionAware sentinelExceptionAware() {
+        return new SentinelExceptionAware();
+    }
+
     @Override
     public void addInterceptors(InterceptorRegistry registry) {
         //Add sentinel interceptor
@@ -48,19 +52,16 @@ private void addSpringMvcInterceptor(InterceptorRegistry registry) {
         //Config
         SentinelWebMvcConfig config = new SentinelWebMvcConfig();
 
-        config.setBlockExceptionHandler(new BlockExceptionHandler() {
-            @Override
-            public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {
-                String resourceName = e.getRule().getResource();
-                //Depending on your situation, you can choose to process or throw
-                if ("/hello".equals(resourceName)) {
-                    //Do something ......
-                    //Write string or json string;
-                    response.getWriter().write("/Blocked by sentinel");
-                } else {
-                    //Handle in global exception handling
-                    throw e;
-                }
+        config.setBlockExceptionHandler((request, response, e) -> {
+            String resourceName = e.getRule().getResource();
+            //Depending on your situation, you can choose to process or throw
+            if ("/hello".equals(resourceName)) {
+                //Do something ......
+                //Write string or json string;
+                response.getWriter().write("/Blocked by sentinel");
+            } else {
+                //Handle in global exception handling
+                throw e;
             }
         });
 

sentinel-adapter/sentinel-spring-webmvc-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/config/SentinelSpringMvcBlockHandlerConfig.java

@@ -16,6 +16,7 @@
 package com.alibaba.csp.sentinel.adapter.spring.webmvc.config;
 
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.ResultWrapper;
+import com.alibaba.csp.sentinel.adapter.spring.webmvc.exception.BizException;
 import com.alibaba.csp.sentinel.slots.block.AbstractRule;
 import com.alibaba.csp.sentinel.slots.block.BlockException;
 import org.slf4j.Logger;
@@ -51,4 +52,11 @@ public ResultWrapper exceptionHandler(Exception e) {
         logger.error("System error", e.getMessage());
         return new ResultWrapper(-1, "System error");
     }
+
+    @ExceptionHandler(BizException.class)
+    @ResponseBody
+    public ResultWrapper bizExceptionHandler(BizException e) {
+        logger.error("Biz error", e.getMessage());
+        return new ResultWrapper(-1, "Biz error");
+    }
 }

sentinel-adapter/sentinel-spring-webmvc-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/controller/TestController.java

@@ -16,6 +16,7 @@
 package com.alibaba.csp.sentinel.adapter.spring.webmvc.controller;
 
 
+import com.alibaba.csp.sentinel.adapter.spring.webmvc.exception.BizException;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RestController;
@@ -47,6 +48,11 @@ public String runtimeException() {
         return "runtimeException";
     }
 
+    @GetMapping("/bizException")
+    public String bizException() {
+        throw new BizException();
+    }
+
     @GetMapping("/exclude/{id}")
     public String apiExclude(@PathVariable("id") Long id) {
         return "Exclude " + id;

sentinel-adapter/sentinel-spring-webmvc-adapter/src/test/java/com/alibaba/csp/sentinel/adapter/spring/webmvc/exception/BizException.java

@@ -0,0 +1,7 @@
+package com.alibaba.csp.sentinel.adapter.spring.webmvc.exception;
+
+/**
+ * @author lemonj
+ */
+public class BizException extends RuntimeException{
+}

sentinel-demo/sentinel-demo-spring-webmvc/src/main/java/com/alibaba/csp/sentinel/demo/spring/webmvc/config/InterceptorConfig.java

@@ -15,12 +15,13 @@
  */
 package com.alibaba.csp.sentinel.demo.spring.webmvc.config;
 
+import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelExceptionAware;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelWebInterceptor;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.SentinelWebTotalInterceptor;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.DefaultBlockExceptionHandler;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.config.SentinelWebMvcConfig;
 import com.alibaba.csp.sentinel.adapter.spring.webmvc.config.SentinelWebMvcTotalConfig;
-
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@@ -39,6 +40,12 @@ public void addInterceptors(InterceptorRegistry registry) {
         addSpringMvcInterceptor(registry);
     }
 
+    @Bean
+    public SentinelExceptionAware sentinelExceptionAware() {
+        //Make exception visible to Sentinel if you have configured ExceptionHandler
+        return new SentinelExceptionAware();
+    }
+
     private void addSpringMvcInterceptor(InterceptorRegistry registry) {
         SentinelWebMvcConfig config = new SentinelWebMvcConfig();