My understanding of how Wait/Notify worked was that the Wait processor would look for the count in the target signal to reach a specific value, at which point it would open and let through any flowfiles that were waiting. I'm not sure if the target value that it's looking for is actually a delta between whatever the cached value is and some internally-stored state that Wait maintains; it would make sense to me if that were the case because it would eliminate the need to keep resetting the counter. But I'm fairly certain that this will not work the way you describe it, where the running_count property has to be set to something on the flowfile in order for the flowfile to go through.
On Tue, Apr 23, 2019 at 10:39 PM Shawn Weeks <swe...@weeksconsulting.us> wrote: > Running into some additional inconsistencies. I’m under the impression > that only the Notify Processor can increment the counter. In example I’m > testing I have Notify that sets the signal count “running_count” to zero > and then immediately after it I have a Notify that increments by 2 yet when > I run the groovy cache dumps script on > http://funnifi.blogspot.com/2016/04/inspecting-your-nifi.html I can see > “running_count” may be set to something much higher like 50 or 60. Another > seems to be that the Wait Processor lets things through that don’t match > the Target Signal Count. For example if the target signal count is 1 then > it’s letting things through that have a target signal count of 2? I’ve got > to be missing something rather obvious. > > > > Thanks > > Shawn > > > > *From:* Shawn Weeks <swe...@weeksconsulting.us> > *Sent:* Tuesday, April 23, 2019 8:32 PM > *To:* users@nifi.apache.org > *Subject:* Implementing Gates with the Wait and Notify Processors > > > > I’m working to implement a flow where for a given source of data I can > only be processing one set at a time due to external dependencies. Each set > needs to go through several different steps so this isn’t just a matter of > limiting concurrency for a single processor. I’m trying to implement this > using Wait and Notify as a gate and I’ve ran into a couple of limitations > that I’m not sure how to get around. I first set my Wait processors to wait > for a specific counter to be reset to zero before allowing a data source > through but I quickly discovered that the Wait Processors tries to divide > the signal counter leading to a divide by zero error. I’m assuming if zero > isn’t a valid value for the signal counter we should disallow it however > since you can’t use the Notify processor to set arbitrary values other than > zero I’m not sure how your supposed to make a 0 or 1 gate. Are you supposed > to have two Notify Processors back to back where one resets the counter to > zero and the next increments by one? That seems a bit clunky. > > > > Thoughts? > > > > Thanks > > Shawn Weeks > -- http://www.google.com/profiles/grapesmoker
