Push RequestContext tolerance into ConcurrencyStrategy

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

@@ -16,7 +16,6 @@
 package com.netflix.hystrix;
 
 import java.lang.ref.Reference;
-import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -51,7 +50,6 @@
 import com.netflix.hystrix.exception.HystrixRuntimeException.FailureType;
 import com.netflix.hystrix.strategy.HystrixPlugins;
 import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
-import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategyDefault;
 import com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable;
 import com.netflix.hystrix.strategy.concurrency.HystrixRequestContext;
 import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier;
@@ -262,21 +260,7 @@ protected AbstractCommand(HystrixCommandGroupKey group, HystrixCommandKey key, H
 
         if (properties.requestLogEnabled().get()) {
             /* store reference to request log regardless of which thread later hits it */
-            if (concurrencyStrategy instanceof HystrixConcurrencyStrategyDefault) {
-              // if we're using the default we support only optionally using a request context
-              if (HystrixRequestContext.isCurrentThreadInitialized()) {
-                currentRequestLog = HystrixRequestLog.getCurrentRequest(concurrencyStrategy);
-              } else {
-                currentRequestLog = null;
-              }
-            } else {
-              // if it's a custom strategy it must ensure the context is initialized
-              if (HystrixRequestLog.getCurrentRequest(concurrencyStrategy) != null) {
-                currentRequestLog = HystrixRequestLog.getCurrentRequest(concurrencyStrategy);
-              } else {
-                currentRequestLog = null;
-              }
-            }
+            currentRequestLog = HystrixRequestLog.getCurrentRequest(concurrencyStrategy);
         } else {
             currentRequestLog = null;
         }

hystrix-core/src/main/java/com/netflix/hystrix/strategy/concurrency/HystrixConcurrencyStrategy.java

@@ -145,16 +145,7 @@ public <T> Callable<T> wrapCallable(Callable<T> callable) {
      * @return {@code HystrixRequestVariable<T>}
      */
     public <T> HystrixRequestVariable<T> getRequestVariable(final HystrixRequestVariableLifecycle<T> rv) {
-        return new HystrixRequestVariableDefault<T>() {
-            @Override
-            public T initialValue() {
-                return rv.initialValue();
-            }
-
-            public void shutdown(T value) {
-                rv.shutdown(value);
-            }
-        };
+        return new HystrixLifecycleForwardingRequestVariable<T>(rv);
     }
 
 }

hystrix-core/src/main/java/com/netflix/hystrix/strategy/concurrency/HystrixLifecycleForwardingRequestVariable.java

@@ -0,0 +1,72 @@
+/**
+ * Copyright 2015 Netflix, Inc.
+ *
+ * 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.netflix.hystrix.strategy.concurrency;
+
+/**
+ * Implementation of {@link HystrixRequestVariable} which forwards to the wrapped
+ * {@link HystrixRequestVariableLifecycle}.
+ * <p>
+ * This implementation also returns null when {@link #get()} is called while the {@link HystrixRequestContext} has not
+ * been initialized rather than throwing an exception, allowing for use in a {@link HystrixConcurrencyStrategy} which
+ * does not depend on an a HystrixRequestContext
+ */
+public class HystrixLifecycleForwardingRequestVariable<T> extends HystrixRequestVariableDefault<T> {
+    private final HystrixRequestVariableLifecycle<T> lifecycle;
+
+    /**
+     * Creates a HystrixRequestVariable which will return data as provided by the {@link HystrixRequestVariableLifecycle}
+     * @param lifecycle lifecycle used to provide values. Must have the same type parameter as the constructed instance.
+     */
+    public HystrixLifecycleForwardingRequestVariable(HystrixRequestVariableLifecycle<T> lifecycle) {
+        this.lifecycle = lifecycle;
+    }
+
+    /**
+     * Delegates to the wrapped {@link HystrixRequestVariableLifecycle}
+     * @return T with initial value or null if none.
+     */
+    @Override
+    public T initialValue() {
+        return lifecycle.initialValue();
+    }
+
+    /**
+     * Delegates to the wrapped {@link HystrixRequestVariableLifecycle}
+     * @param value
+     *            of request variable to allow cleanup activity.
+     *            <p>
+     *            If nothing needs to be cleaned up then nothing needs to be done in this method.
+     */
+    @Override
+    public void shutdown(T value) {
+        lifecycle.shutdown(value);
+    }
+
+    /**
+     * Return null if the {@link HystrixRequestContext} has not been initialized for the current thread.
+     * <p>
+     * If {@link HystrixRequestContext} has been initialized then call method in superclass:
+     * {@link HystrixRequestVariableDefault#get()}
+     */
+    @Override
+    public T get() {
+        if (!HystrixRequestContext.isCurrentThreadInitialized()) {
+            return null;
+        }
+        return super.get();
+    }
+
+}

hystrix-core/src/main/java/com/netflix/hystrix/strategy/concurrency/HystrixRequestVariableHolder.java

@@ -25,7 +25,7 @@
  * <p>
  * This is used as a layer between the actual {@link HystrixRequestVariable} and calling code to allow injected implementations of {@link HystrixConcurrencyStrategy}.
  * <p>
- * Typically a {@link HystrixRequestVariable} would be statically references (similar to a ThreadLocal) but to allow dynamic injection we instead statically reference this class which can then
+ * Typically a {@link HystrixRequestVariable} would be statically referenced (similar to a ThreadLocal) but to allow dynamic injection we instead statically reference this class which can then
  * dynamically fetch the correct implementation and statically retain an instance across threads within a context (such as {@link HystrixRequestContext}.
  * 
  * @param <T>

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

@@ -2717,12 +2717,7 @@ public void testBasicExecutionWorksWithoutRequestVariable() {
             fail("We received an exception => " + e.getMessage());
         }
 
-        try {
-            HystrixRequestLog.getCurrentRequest();
-            fail("Should not have a RequestLog when RequestContext not initialized");
-        } catch (IllegalStateException ise) {
-            //expected
-        }
+        assertNull(HystrixRequestLog.getCurrentRequest());
     }
 
     /**
@@ -2749,13 +2744,6 @@ public void testCacheKeyExecutionRequiresRequestVariable() {
         } catch (Exception e) {
             e.printStackTrace();
         }
-
-        try {
-            HystrixRequestLog.getCurrentRequest();
-            fail("Should not have a RequestLog when RequestContext not initialized");
-        } catch (IllegalStateException ise) {
-            //expected
-        }
     }
 
     /**