Process Group level counter

@Emery 

1. Counters: NiFi counters only exist in NiFi heap, so values are lost if NiFi is restarted. 
2. Parameter Contexts are static defined values intended use across many components thus along a single place to update when needed.

I don't know what your use case is for these counters, but perhaps you could use the following processors to maintain a count and be able to fetch the value when needed in your dataflows:

• PutDistributedMapCache 1.28.0
• FetchDistributedMapCache 1.28.0

So you can Fetch current value from cache, update it, and put replace value in cache. 

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Thank you,
Matt

Hi,

Thanks for your reply.

It's ok for me if the Counter values are lost when NiFi is restarted. I can deal with that. Can I read their values in ExecuteScript / ExecuteGroovyScript?

I used this to increment it, but I wasn't able to read the value itself.

session.adjustCounter("my_counter", 1, true)

I'll look into Distributed Map Cache. I'm unfamiliar with it. Thank you!

I've read up a bit onDistributedMapCacheServer and setting up and accessing ports, and its purpose really feels larger than what I'm looking for.  😞 

I'd just like the ability to maintain a simple counter within a process group that I can read, increment and reset, best within a groovy script.

Parameters and Counters, or something else if it exists, would totally suit the purpose. Is there a way I can read counter values in ExecuteScript / ExecuteGroovyScript that I'm missing?

Thanks!

I read about that possibility. Also with that, making a rest api call for a simple "global variable" within a process group or across a single process flow uses more processing resources and time than I would think is optimal, but I may be wrong.

That's unfortunate. All I require is a simple counter. 😞