Merge pull request Netflix#1093 from caarlos0/request-cache

Fixed NPE on request cache when HystrixRequestContext is not initialized

Author: mattrjacobs

hystrix-core/src/main/java/com/netflix/hystrix/HystrixRequestCache.java

@@ -23,6 +23,7 @@
 import rx.Observable;
 
 import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
+import com.netflix.hystrix.strategy.concurrency.HystrixRequestContext;
 import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableDefault;
 import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableHolder;
 import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableLifecycle;
@@ -100,6 +101,9 @@ private static HystrixRequestCache getInstance(RequestCacheKey rcKey, HystrixCon
     /* package */<T> Observable<T> get(String cacheKey) {
         ValueCacheKey key = getRequestCacheKey(cacheKey);
         if (key != null) {
+            if (!HystrixRequestContext.isCurrentThreadInitialized()) {
+                throw new IllegalStateException("Request caching is not available. Maybe you need to initialize the HystrixRequestContext?");
+            }
             /* look for the stored value */
             return (Observable<T>) requestVariableForCache.get(concurrencyStrategy).get(key);
         }

hystrix-core/src/test/java/com/netflix/hystrix/HystrixRequestCacheTest.java

@@ -66,6 +66,14 @@ public void testCache() {
         }
     }
 
+    @Test(expected = IllegalStateException.class)
+    public void testCacheWithoutContext() {
+        HystrixRequestCache.getInstance(
+            HystrixCommandKey.Factory.asKey("command1"),
+            HystrixConcurrencyStrategyDefault.getInstance()
+        ).get("any");
+    }
+
     @Test
     public void testClearCache() {
         HystrixConcurrencyStrategy strategy = HystrixConcurrencyStrategyDefault.getInstance();