Very cool ! Thank you Rehman! On Fri, 24 Jan 2020, 06:12 Maximilian Michels, <m...@apache.org> wrote:
> Great work! That makes timers so much easier to use and also adds new > use cases. Thank you Rehman. > > On 23.01.20 22:54, Robert Burke wrote: > > Fascinating and great work! *makes notes for an eventual Go SDK > > implementation* > > > > On Thu, Jan 23, 2020, 1:51 PM Luke Cwik <lc...@google.com > > <mailto:lc...@google.com>> wrote: > > > > This is great. Thanks for the contribution Rehman. > > > > On Thu, Jan 23, 2020 at 10:09 AM Reuven Lax <re...@google.com > > <mailto:re...@google.com>> wrote: > > > > Thanks to a lot of hard work by Rehman, Beam now supports > > dynamic timers. As a reminder, this was discussed on the dev > > list some time back. > > > > As background, previously one had to statically declare all > > timers in your code. So if you wanted to have two timers, you > > needed to create two timer variables and two callbacks - one for > > each timer. A number of users kept hitting stumbling blocks > > where they needed a dynamic set of timers (often based on the > > element), which was not supported in Beam. The workarounds were > > quite ugly and complicated. > > > > The new support allows declaring a TimerMap, which is a map of > > timers. Each TimerMap is scoped by a family name, so you can > > create multiple TimerMaps each with its own callback. The use > > looks as follows: > > > > class MyDoFn extends DoFn<...> { > > @TimerFamily("timers") > > private final TimerSpec timerMap = > > TimerSpecs.timerMap(TimeDomain.EVENT_TIME); > > > > @ProcessElement > > public void process(@TimerFamily("timers") TimerMap > > timers, @Element Type e) { > > timers.set("mainTimer", timestamp); > > timers.set("actionType" + e.getActionType(), timestamp); > > } > > > > @OnTimerFamily . > > public void onTimer(@TimerId String timerId) { > > System.out.println("Timer fired. id: " + timerId); > > } > > } > > > > This currently works for the Flink and the Dataflow runners. > > > > Thank you Rehman for getting this done! Beam users will find it > > very valuable. > > > > Reuven > > >
