Due to the fact that current component uses artificial names for properties set via UI and then maps those properties to the actual names used by Kafka, we can not rely on NiFi UI to display an error if user attempts to set a dynamic property which will eventually map to the same Kafka property. So, I’ve decided that any dynamic property will simply override an existing property with WARNING message displayed. It is actually consistent with how Kafka does it and displayed the overrides in the console. Updated the relevant annotation description.
It is also worth to mentioned that current code was using an old property from Kafka 0.7 (“zk.connectiontimeout.ms”) which is no longer present in Kafka 0.8 (WARN Timer-Driven Process Thread-7 utils.VerifiableProperties:83 - Property zk.connectiontimeout.ms is not valid). The add/override strategy would provide for more flexibility when dealing with Kafka volatile configuration until things will settle down and we can get some sensible defaults in place.
While doing it addressed the following issues that were discovered while making modification and testing:
ISSUE: When GetKafka started and there are no messages in Kafka topic the onTrigger(..) method would block due to the fact that Kafka’s ConsumerIterator.hasNext() blocks. When attempt was made to stop GetKafka would stops successfully due to the interrupt. However in UI it would appear as ERROR based on the fact that InterruptException was not handled.
RESOLUTION: After discussing it with @markap14 the the general desire is to let the task exit as quick as possible and that the whole thread maintenance logic was there initially due to the fact that there was no way to tell Kafka consumer to return immediately if there are no events. In this patch we are now using ‘consumer.timeout.ms’ property of Kafka and setting its value to 1 millisecond (default is -1 - always block infinitely). This ensures that tasks that attempted to read an empty topic will exit immediately just to be rescheduled by NiFi based on user configurations.
ISSUE: Kafka would not release FlowFile with events if it didn’t have enough to complete the batch since it would block waiting for more messages (based on the blocking issue described above).
RESOLUTION: The invocation of hasNext() results in Kafka’s ConsumerTimeoutException which is handled in the catch block where the FlowFile with partial batch will be released to success. Not sure if we need to put a WARN message. In fact in my opinion we should not as it may create unnecessary confusion.
ISSUE: When configuring a consumer for topic and specifying multiple concurrent consumers in ‘topicCountMap’ based on 'context.getMaxConcurrentTasks()’ each consumer would bind to a topic partition. If you have less partitions then the value returned by 'context.getMaxConcurrentTasks()’ you would essentially allocate Kafka resources that would never get a chance to receive a single message (see more here https://cwiki.apache.org/confluence/display/KAFKA/Consumer+Group+Example).
RESOLUTION: Logic was added to determine the amount of partitions for a topic and in the event where 'context.getMaxConcurrentTasks()’ value is greater than the amount of partitions, the partition count will be used to when creating ‘topicCountMap’ and WARNING message will be displayed)see code). Unfortunately we can’t do anything with the actual tasks, but based on current state of the code they will exit immediately just to be rescheduled where the process will repeat. NOTE: That is not ideal as it will be rescheduling tasks that will never have a chance to do anything, but at least it could be fixed on the user side after reading the warning message.
NIFI-1192 added dynamic properties support for PutKafka
NIFI-1192 polishing
NIFI-1192 polished and addressed PR comments
NIFI-980 Add support for HTTP Digest authentication to InvokeHttp
NIFI-1080 Provide additional InvokeHttp unit tests
NIFI-1133 InvokeHTTP Processor does not save Location header for 3xx responses
NIFI-1009 InvokeHTTP should be able to be scheduled without any incoming connection for GET operations
NIFI-61 Multiple improvements for InvokeHTTP inclusive of providing unique tx.id across clusters, dynamic HTTP header properties
Signed-off-by: Aldrin Piri <aldrin@apache.org>
connections are scheduled to run, even if the connections have no FlowFiles;
expose these details to processor developers; update documentation
Signed-off-by: Aldrin Piri <aldrin@apache.org>
Mark Payne
Johnathan Gilday
joewitt
Joe Skora
Matt Gilman
Oleg Zhurakousky
Bryan Bende
Jenn Barnabee
Aldrin Piri
Joseph Percivall
Tony Kurc
Naveen Madhire