I second caffeine as well, I have used it very effectively in controller services.
> On May 1, 2018, at 9:12 AM, Otto Fowler <ottobackwa...@gmail.com> wrote: > > We used guava in Apache Metron, but have switched to > https://github.com/ben-manes/caffeine <https://github.com/ben-manes/caffeine>. > I would recommend taking a look at that too. > > > > On May 1, 2018 at 10:09:00, Charlie Meyer (charlie.me...@civitaslearning.com > <mailto:charlie.me...@civitaslearning.com>) wrote: > >> We do something very similar in a custom controller service and utilize a >> guava cache (https://github.com/google/guava/wiki/CachesExplained >> <https://github.com/google/guava/wiki/CachesExplained>) and have found it to >> work quite well >> >> On Tue, May 1, 2018 at 9:06 AM, Tim Dean <tim.d...@gmail.com >> <mailto:tim.d...@gmail.com>> wrote: >> Thanks Otto - >> >> Unfortunately, the service being called doesn’t currently support full HTTP >> cache semantics at this time. I could add full support, and it is probably >> the right thing to do in the long run. But for now I was hoping for a >> solution that didn’t require significant enhancement to the web service. >> >> -Tim >> >> >>> On May 1, 2018, at 5:47 AM, Otto Fowler <ottobackwa...@gmail.com >>> <mailto:ottobackwa...@gmail.com>> wrote: >>> >>> https://hc.apache.org/httpcomponents-client-ga/tutorial/html/caching.html >>> <https://hc.apache.org/httpcomponents-client-ga/tutorial/html/caching.html> >>> ? >>> >>> >>> On May 1, 2018 at 00:01:58, Tim Dean (tim.d...@gmail.com >>> <mailto:tim.d...@gmail.com>) wrote: >>> >>>> Hello, >>>> >>>> I have a custom NiFi controller service that retrieves data from an >>>> external web service via HTTP requests. The results from these HTTP >>>> requests will be needed at various points throughout my process flow. In >>>> some situations, I could end up needing to access the HTTP response dozens >>>> or even hundreds of times. >>>> >>>> Given that the results of the HTTP request rarely change, I’d like them to >>>> be cached by my service and returned to my processors when needed. I’d >>>> need some way to explicitly clear the cache for those occasions when the >>>> data in the service does change. >>>> >>>> I’ve looked at using the DistributedMapCacheClientService implementation >>>> to cache my web service’s results, but it seems like that connects to a >>>> server via a socket connection and that doesn’t seem like it would be all >>>> that much more efficient than calling the web service directly. I’ve also >>>> looked at using the service’s state manager to store the results as state, >>>> but my data is a little more complex than what the documentation for state >>>> suggests is optimal: I don’t think my total map size will get to 1MB in >>>> size but it could be possible. >>>> >>>> Am I overthinking this? Would a simpler solution like creating a simple >>>> Java HashMap inside my controller service be adequate? I could empty the >>>> contents of the hash map whenever the controller services is >>>> enabled/disabled. Would the memory used by this kind of simplified local >>>> caching cause problems somewhere down the line? >>>> >>>> Are there other caching strategies I should be considering? >>>> >>>> Thanks >>>> >>>> -Tim
