Support customized block page HTTP status in sentinel-web-servlet-adapter (#1112)

* Return canonical status 429 in the default block handler of sentinel-web-servlet-adapter.
* Add a `csp.sentinel.web.servlet.block.page.http.status` property to support customized block status configuration.

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

@@ -18,8 +18,10 @@ package com.alibaba.csp.sentinel.adapter.servlet.config;
 import com.alibaba.csp.sentinel.adapter.servlet.CommonFilter;
 import com.alibaba.csp.sentinel.adapter.servlet.CommonTotalFilter;
 import com.alibaba.csp.sentinel.config.SentinelConfig;
+import com.alibaba.csp.sentinel.util.StringUtil;
 
 /**
+ * @author zhaoyuguang
  * @author leyou
  */
 public class WebServletConfig {
@@ -28,6 +30,10 @@ public class WebServletConfig {
 
     public static final String BLOCK_PAGE = "csp.sentinel.web.servlet.block.page";
 
+    public static final String BLOCK_PAGE_HTTP_STATUS = "csp.sentinel.web.servlet.block.page.http.status";
+
+    private static final int HTTP_STATUS_TOO_MANY_REQUESTS = 429;
+
     /**
      * Get redirecting page when Sentinel blocking for {@link CommonFilter} or
      * {@link CommonTotalFilter} occurs.
@@ -41,4 +47,31 @@ public class WebServletConfig {
     public static void setBlockPage(String blockPage) {
         SentinelConfig.setConfig(BLOCK_PAGE, blockPage);
     }
+
+    /**
+     * Return status 429 in the default block page,
+     * you can use -Dcsp.sentinel.web.servlet.block.page.http.status=200 or other http status,
+     * to set http status which you want of the default block page.
+     * When csp.sentinel.web.servlet.block.page.http.status is empty or not number,
+     * the block page http status will be automatically set to 429(Too Many Requests).
+     *
+     * @return block page http status
+     */
+    public static int getBlockPageHttpStatus() {
+        String value = SentinelConfig.getConfig(BLOCK_PAGE_HTTP_STATUS);
+        if (StringUtil.isEmpty(value)) {
+            setBlockPageHttpStatus(HTTP_STATUS_TOO_MANY_REQUESTS);
+            return HTTP_STATUS_TOO_MANY_REQUESTS;
+        }
+        try {
+            return Integer.parseInt(SentinelConfig.getConfig(BLOCK_PAGE_HTTP_STATUS));
+        } catch (NumberFormatException e) {
+            setBlockPageHttpStatus(HTTP_STATUS_TOO_MANY_REQUESTS);
+        }
+        return HTTP_STATUS_TOO_MANY_REQUESTS;
+    }
+
+    public static void setBlockPageHttpStatus(int httpStatus) {
+        SentinelConfig.setConfig(BLOCK_PAGE_HTTP_STATUS, String.valueOf(httpStatus));
+    }
 }

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

@@ -27,6 +27,7 @@ import com.alibaba.csp.sentinel.util.StringUtil;
 /**
  * Util class for web servlet filter.
  *
+ * @author zhaoyuguang
  * @author youji.zj
  * @author Eric Zhao
  */
@@ -65,7 +66,7 @@ public final class FilterUtil {
         }
 
         if (StringUtil.isBlank(WebServletConfig.getBlockPage())) {
-            writeDefaultBlockedPage(response);
+            writeDefaultBlockedPage(response, WebServletConfig.getBlockPageHttpStatus());
         } else {
             String redirectUrl = WebServletConfig.getBlockPage() + "?http_referer=" + url.toString();
             // Redirect to the customized block page.
@@ -73,7 +74,8 @@ public final class FilterUtil {
         }
     }
 
-    private static void writeDefaultBlockedPage(HttpServletResponse response) throws IOException {
+    private static void writeDefaultBlockedPage(HttpServletResponse response, int httpStatus) throws IOException {
+        response.setStatus(httpStatus);
         PrintWriter out = response.getWriter();
         out.print(DEFAULT_BLOCK_MSG);
         out.flush();

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

@@ -41,6 +41,7 @@ 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.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.test.web.servlet.MockMvc;
@@ -50,6 +51,7 @@ import static org.springframework.test.web.servlet.request.MockMvcRequestBuilder
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
 
 /**
+ * @author zhaoyuguang
  * @author Eric Zhao
  */
 @RunWith(SpringRunner.class)
@@ -111,11 +113,17 @@ public class CommonFilterTest {
     private void testCommonBlockAndRedirectBlockPage(String url, ClusterNode cn) throws Exception {
         configureRulesFor(url, 0);
         // The request will be blocked and response is default block message.
+        WebServletConfig.setBlockPageHttpStatus(HttpStatus.OK.value());
         this.mvc.perform(get(url).accept(MediaType.TEXT_PLAIN))
             .andExpect(status().isOk())
             .andExpect(content().string(FilterUtil.DEFAULT_BLOCK_MSG));
         assertEquals(1, cn.blockQps(), 0.01);
 
+        WebServletConfig.setBlockPageHttpStatus(HttpStatus.TOO_MANY_REQUESTS.value());
+        this.mvc.perform(get(url).accept(MediaType.TEXT_PLAIN))
+                .andExpect(status().isTooManyRequests())
+                .andExpect(content().string(FilterUtil.DEFAULT_BLOCK_MSG));
+
         // Test for redirect.
         String redirectUrl = "http://some-location.com";
         WebServletConfig.setBlockPage(redirectUrl);
@@ -192,7 +200,7 @@ public class CommonFilterTest {
             .andExpect(content().string(HELLO_STR));
         // This will be blocked.
         this.mvc.perform(get(url).accept(MediaType.TEXT_PLAIN).header(headerName, limitOrigin))
-            .andExpect(status().isOk())
+            .andExpect(status().isTooManyRequests())
             .andExpect(content().string(FilterUtil.DEFAULT_BLOCK_MSG));
         this.mvc.perform(get(url).accept(MediaType.TEXT_PLAIN))
             .andExpect(status().isOk())

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

@@ -41,6 +41,7 @@ import static org.springframework.test.web.servlet.request.MockMvcRequestBuilder
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
 
 /**
+ * @author zhaoyuguang
  * @author Roger Law
  */
 @RunWith(SpringRunner.class)
@@ -107,7 +108,7 @@ public class CommonFilterMethodTest {
         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(status().isTooManyRequests())
                 .andExpect(content().string(FilterUtil.DEFAULT_BLOCK_MSG));
         assertEquals(1, cnGet.blockQps(), 0.01);