[NIFI-526] GetHTTP may not release writeLock

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.0.2
• Fix Version/s: 0.1.0
• Component/s: Extensions
• Labels: beginner newbie
• Assignee: Joe Witt
• Reporter: Mark Latimer
• Created: 20/Apr/15 15:39
• Updated: 29/Apr/15 11:53
• Resolved: 28/Apr/15 19:37

Description

GetHTTP onTrigger process contains a path that will obtain and not release the writeLock.
This happens if enough time elapses between the first and second check of timeToPersist.

Also the readLock locked and unlocked with no meaningful work in between.

GetHTTP.java

		if ((etag != null || lastModified != null) && readLock.tryLock()) {
                    try {
			//first check of timeToPersist against current time
                        if (timeToPersist < System.currentTimeMillis()) {
			    readLock.unlock();
			    //obtain writeLock
                            writeLock.lock();
			    //check time to persist again, this result may be different
			    //if the result is different because enough time has elapsed the lock is not released
                            if (timeToPersist < System.currentTimeMillis()) {
                                try {
                        
				 ...
         
        		         } finally {
	                            readLock.lock();
				    //release writeLock only if the second check of timeToPresist is before now.

                                    writeLock.unlock();
                                }
                            }
                        }
                    } finally {
                        readLock.unlock();
                    }
                }