Hey Boris, Using the UpdateAttribute and RouteOnAttribute approach is only necessary when you want to retry N number of times (or for some time period) and after that elapses to treat the data differently. Most of the time, though, what is used is to simply loop the 'failure' relationship back to the processor itself. So failures would simply remain in the flow, trying indefinitely. When a processor is unable to communicate with some external service due to some intermittent issue, that processor generally should "yield", meaning that the processor will not be triggered for some amount of time (by default it is 1 second).
So in this way, it's very simple to just say "keep trying until you're successful." You could also set "age-off" to occur so that if the data is more than say 1 hour old you can have nifi automatically just discard the data. There are some situations, though, in which users will need to try for say 10 times and then route the data differently. We could definitely improve that experience instead of having to use UpdateAttribute / RouteOnAttribute. But from my experience simply looping until successful is the most common scenario and so that's probably why we've not really seen much traction there. Thanks -Mark On Mar 6, 2018, at 3:02 PM, Boris Tyukin <[email protected]<mailto:[email protected]>> wrote: Just found this Jira https://issues.apache.org/jira/browse/NIFI-90 I am surprised it has not got any traction after 3 years...Having used Apache Airflow for a while, I am looking to retry capabilities in NiFi and it seems it comes down to "build your own" flow approach, that would handle retries in a loop and then sleeping for some time. The best alternative solution I found was suggested by Alessio Palma<https://community.hortonworks.com/users/16011/ozw1z5rd.html> https://community.hortonworks.com/questions/56167/is-there-wait-processor-in-nifi.html IMHO it still would be nice to have retry capabilities like with Apache Airflow. You can specify a global retry behavior for a flow or specify retry options per task/processor. This helps a lot to deal with intermittent issues, like losing network connection or source database system, being down for maintenance. Airflow can also send an email on retry and supports a bunch of other parameters around retries: https://airflow.apache.org/code.html#baseoperator * retries (int) – the number of retries that should be performed before failing the task * retry_delay (timedelta) – delay between retries * retry_exponential_backoff (bool) – allow progressive longer waits between retries by using exponential backoff algorithm on retry delay (delay will be converted into seconds) * max_retry_delay (timedelta) – maximum delay interval between retries * on_retry_callback – much like the on_failure_callback except that it is executed when retries occur. Is everyone using UpdateAttribute and RouteOnAttribute and Sleep method to implement retries? thanks, Boris
