Early unsubscribe hook test

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

@@ -384,13 +384,23 @@ public void call() {
                 if (_cmd.commandState.compareAndSet(CommandState.OBSERVABLE_CHAIN_CREATED, CommandState.UNSUBSCRIBED)) {
                     if (!_cmd.executionResult.containsTerminalEvent()) {
                         _cmd.eventNotifier.markEvent(HystrixEventType.CANCELLED, _cmd.commandKey);
+                        try {
+                            executionHook.onUnsubscribe(_cmd);
+                        } catch (Throwable hookEx) {
+                            logger.warn("Error calling HystrixCommandExecutionHook.onUnsubscribe", hookEx);
+                        }
                         _cmd.executionResultAtTimeOfCancellation = _cmd.executionResult
                                 .addEvent((int) (System.currentTimeMillis() - _cmd.commandStartTimestamp), HystrixEventType.CANCELLED);
                     }
                     handleCommandEnd(false); //user code never ran
                 } else if (_cmd.commandState.compareAndSet(CommandState.USER_CODE_EXECUTED, CommandState.UNSUBSCRIBED)) {
                     if (!_cmd.executionResult.containsTerminalEvent()) {
                         _cmd.eventNotifier.markEvent(HystrixEventType.CANCELLED, _cmd.commandKey);
+                        try {
+                            executionHook.onUnsubscribe(_cmd);
+                        } catch (Throwable hookEx) {
+                            logger.warn("Error calling HystrixCommandExecutionHook.onUnsubscribe", hookEx);
+                        }
                         _cmd.executionResultAtTimeOfCancellation = _cmd.executionResult
                                 .addEvent((int) (System.currentTimeMillis() - _cmd.commandStartTimestamp), HystrixEventType.CANCELLED);
                     }
@@ -2169,6 +2179,11 @@ public <T> void onCacheHit(HystrixInvokable<T> commandInstance) {
             actual.onCacheHit(commandInstance);
         }
 
+        @Override
+        public <T> void onUnsubscribe(HystrixInvokable<T> commandInstance) {
+            actual.onUnsubscribe(commandInstance);
+        }
+
         @SuppressWarnings({ "unchecked", "rawtypes" })
         private <T> HystrixCommand<T> getHystrixCommandFromAbstractIfApplicable(HystrixInvokable<T> commandInstance) {
             if (commandInstance instanceof HystrixCommand) {

hystrix-core/src/main/java/com/netflix/hystrix/strategy/executionhook/HystrixCommandExecutionHook.java

@@ -216,6 +216,17 @@ public <T> void onCacheHit(HystrixInvokable<T> commandInstance) {
         //do nothing by default
     }
 
+    /**
+     * Invoked with the command is unsubscribed before a terminal state
+     *
+     * @param commandInstance The executing HystrixInvokable instance.
+     *
+     * @since 1.5.9
+     */
+    public <T> void onUnsubscribe(HystrixInvokable<T> commandInstance) {
+        //do nothing by default
+    }
+
     /**
      * DEPRECATED: Change usages of this to {@link #onExecutionStart}.
      *

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

@@ -4010,6 +4010,55 @@ public void call(TestHystrixCommand<Integer> command) {
                 });
     }
 
+    @Test
+    public void testExecutionHookEarlyUnsubscribe() {
+        System.out.println("Running command.observe(), awaiting terminal state of Observable, then running assertions...");
+        final CountDownLatch latch = new CountDownLatch(1);
+
+        TestHystrixCommand<Integer> command = getCommand(ExecutionIsolationStrategy.THREAD, AbstractTestHystrixCommand.ExecutionResult.SUCCESS, 1000);
+        Observable<Integer> o = command.observe();
+
+        Subscription s = o.
+                doOnUnsubscribe(new Action0() {
+                    @Override
+                    public void call() {
+                        System.out.println(System.currentTimeMillis() + " : " + Thread.currentThread().getName() + " : OnUnsubscribe");
+                        latch.countDown();
+                    }
+                }).
+                subscribe(new Subscriber<Integer>() {
+                    @Override
+                    public void onCompleted() {
+                        System.out.println(System.currentTimeMillis() + " : " + Thread.currentThread().getName() + " : OnCompleted");
+                        latch.countDown();
+                    }
+
+                    @Override
+                    public void onError(Throwable e) {
+                        System.out.println(System.currentTimeMillis() + " : " + Thread.currentThread().getName() + " : OnError : " + e);
+                        latch.countDown();
+                    }
+
+                    @Override
+                    public void onNext(Integer i) {
+                        System.out.println(System.currentTimeMillis() + " : " + Thread.currentThread().getName() + " : OnNext : " + i);
+                    }
+        });
+
+        try {
+            Thread.sleep(15);
+            s.unsubscribe();
+            latch.await(3, TimeUnit.SECONDS);
+            TestableExecutionHook hook = command.getBuilder().executionHook;
+            assertTrue(hook.commandEmissionsMatch(0, 0, 0));
+            assertTrue(hook.executionEventsMatch(0, 0, 0));
+            assertTrue(hook.fallbackEventsMatch(0, 0, 0));
+            assertEquals("onStart - onThreadStart - !onRunStart - onExecutionStart - onUnsubscribe - onThreadComplete - ", hook.executionSequence.toString());
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     /**
      * Short-circuit? : NO
      * Thread/semaphore: THREAD

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

@@ -210,8 +210,14 @@ public <T> void onCacheHit(HystrixInvokable<T> commandInstance) {
         recordHookCall(executionSequence, "onCacheHit");
     }
 
+    @Override
+    public <T> void onUnsubscribe(HystrixInvokable<T> commandInstance) {
+        super.onUnsubscribe(commandInstance);
+        recordHookCall(executionSequence, "onUnsubscribe");
+    }
+
     /**
-     * DEPRECATED METHODS FOLLOW.  The string representation starts with `!D!` to distinguish
+     * DEPRECATED METHODS FOLLOW.  The string representation starts with `!` to distinguish
      */
 
     AtomicInteger startExecute = new AtomicInteger();