Fix rate limiter bug.

eureka-core/src/main/java/com/netflix/eureka/RateLimitingFilter.java

@@ -35,6 +35,8 @@
 import com.netflix.appinfo.EurekaClientIdentity;
 import com.netflix.eureka.util.EurekaMonitors;
 import com.netflix.eureka.util.RateLimiter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Rate limiting filter, with configurable threshold above which non-privileged clients
@@ -81,6 +83,8 @@
  */
 public class RateLimitingFilter implements Filter {
 
+    private static final Logger logger = LoggerFactory.getLogger(RateLimitingFilter.class);
+
     private static final Set<String> DEFAULT_PRIVILEGED_CLIENTS = new HashSet<String>(
             Arrays.asList(EurekaClientIdentity.DEFAULT_CLIENT_NAME, EurekaServerIdentity.DEFAULT_SERVER_NAME)
     );
@@ -127,11 +131,12 @@ private static Target getTarget(ServletRequest request) {
         Target target = Target.Other;
         if (request instanceof HttpServletRequest) {
             HttpServletRequest httpRequest = (HttpServletRequest) request;
+            String pathInfo = httpRequest.getRequestURI();
 
-            if ("GET".equals(httpRequest.getMethod())) {
-                Matcher matcher = TARGET_RE.matcher(httpRequest.getPathInfo());
+            if ("GET".equals(httpRequest.getMethod()) && pathInfo != null) {
+                Matcher matcher = TARGET_RE.matcher(pathInfo);
                 if (matcher.matches()) {
-                    if (matcher.groupCount() == 0 || "/".equals(matcher.group(1))) {
+                    if (matcher.groupCount() == 0 || matcher.group(1) == null || "/".equals(matcher.group(1))) {
                         target = Target.FullFetch;
                     } else if ("/delta".equals(matcher.group(1))) {
                         target = Target.DeltaFetch;
@@ -140,12 +145,24 @@ private static Target getTarget(ServletRequest request) {
                     }
                 }
             }
+            if (target == Target.Other) {
+                logger.debug("URL path {} not matched by rate limiting filter", pathInfo);
+            }
         }
         return target;
     }
 
     private static boolean isRateLimited(HttpServletRequest request, Target target) {
-        return !isPrivileged(request) && isOverloaded(target);
+        if (isPrivileged(request)) {
+            logger.debug("Privileged {} request", target);
+            return false;
+        }
+        if (isOverloaded(target)) {
+            logger.debug("Overloaded {} request; discarding it", target);
+            return true;
+        }
+        logger.debug("{} request admitted", target);
+        return false;
     }
 
     private static boolean isPrivileged(HttpServletRequest request) {
@@ -162,7 +179,7 @@ private static boolean isOverloaded(Target target) {
         int fetchWindowSize = config().getRateLimiterRegistryFetchAverageRate();
         boolean overloaded = !registryFetchRateLimiter.acquire(maxInWindow, fetchWindowSize);
 
-        if (target == Target.FullFetch || target == Target.Application) {
+        if (target == Target.FullFetch) {
             int fullFetchWindowSize = config().getRateLimiterFullFetchAverageRate();
             overloaded |= !registryFullFetchRateLimiter.acquire(maxInWindow, fullFetchWindowSize);
         }

eureka-core/src/main/java/com/netflix/eureka/resources/ApplicationResource.java

@@ -26,6 +26,7 @@
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.Response.Status;
 
+import com.netflix.eureka.util.EurekaMonitors;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -75,6 +76,9 @@ public Response getApplication(@PathParam("version") String version,
         if (!PeerAwareInstanceRegistry.getInstance().shouldAllowAccess(false)) {
             return Response.status(Status.FORBIDDEN).build();
         }
+
+        EurekaMonitors.GET_APPLICATION.increment();
+
         CurrentRequestVersion.set(Version.toEnum(version));
         KeyType keyType = KeyType.JSON;
         if (acceptHeader == null || !acceptHeader.contains("json")) {

eureka-core/src/main/java/com/netflix/eureka/util/EurekaMonitors.java

@@ -55,6 +55,7 @@ public enum EurekaMonitors {
     GET_ALL("getAllCounter", "Number of total registry queries seen since startup"),
     GET_ALL_WITH_REMOTE_REGIONS("getAllWithRemoteRegionCounter",
             "Number of total registry queries with remote regions, seen since startup"),
+    GET_APPLICATION("getApplicationCounter", "Number of total application queries seen since startup"),
     REGISTER("registerCounter", "Number of total registers seen since startup"),
     EXPIRED("expiredCounter", "Number of total expired leases since startup"),
     STATUS_UPDATE("statusUpdateCounter", "Number of total admin status updates since startup"),

eureka-core/src/test/java/com/netflix/eureka/RateLimitingFilterTest.java

@@ -150,7 +150,7 @@ public void testCustomClientThrottlingCandidatesCounter() throws Exception {
 
     private void whenRequest(String path, String client) {
         when(request.getMethod()).thenReturn("GET");
-        when(request.getPathInfo()).thenReturn(path);
+        when(request.getRequestURI()).thenReturn(path);
         when(request.getHeader(AbstractEurekaIdentity.AUTH_NAME_HEADER_KEY)).thenReturn(client);
     }
 }

eureka-server/WEB-INF/web.xml

@@ -45,6 +45,14 @@
     <url-pattern>/*</url-pattern>
   </filter-mapping>
 
+  <!-- Uncomment this to enable rate limiter filter.
+  <filter-mapping>
+    <filter-name>rateLimitingFilter</filter-name>
+    <url-pattern>/v2/apps</url-pattern>
+    <url-pattern>/v2/apps/*</url-pattern>
+  </filter-mapping>
+  -->
+
   <filter-mapping>
     <filter-name>jersey</filter-name>
     <url-pattern>/*</url-pattern>