Just to circle back, making the Runner TestStream compatible would allow for exercising existing tests for trigger functionality. The DirectRunner is the only one which currently does this but we hope all Runners will follow so that each Runner has a suite of tests they can rely on to verify triggering semantics/behavior.
On Wed, Jun 7, 2017 at 11:39 AM, Shen Li <cs.she...@gmail.com> wrote: > Hi Kenn, > > Thanks for the explanation. Yes, I will test the runner directly. > > Shen > > On Wed, Jun 7, 2017 at 12:35 PM, Kenneth Knowles <k...@google.com.invalid> > wrote: > > > Hi Shen, > > > > There are four points (at least) to why we don't currently have custom > > triggers: > > > > 1. The existing trigger state machine implementations use low-level and > > difficult APIs that are not available to users. > > 2. If we make triggers a UDF then we need to cross the Fn API. It makes a > > lot more portability work in terms of engineering and also is really the > > center of a tight loop. Instead, runners can very efficiently execute > them > > directly. > > 3. There are many state machines that are not valid triggers. > > 4. Some triggers can be more efficiently executed directly from their > > syntax than from a state machine. > > > > Eventually, we may add some kind of triggering UDF. But we may not, > because > > if you want something like a custom trigger for some use case, then you > can > > do it with state & timers in ParDo. > > > > But it sounds like you need it for some quite specific testing. Since > > "watermark advance event" is a runner-specific concept not part of the > > model (a runner doesn't have to actually reify such events) maybe you > just > > want to test your runner details directly. > > > > Kenn > > > > On Wed, Jun 7, 2017 at 10:22 AM, Shen Li <cs.she...@gmail.com> wrote: > > > > > Hi Lukasz, > > > > > > Thanks again for the suggestion. Is there any reason for not allowing > > users > > > create custom triggers? > > > > > > Shen > > > > > > On Wed, Jun 7, 2017 at 12:13 PM, Lukasz Cwik <lc...@google.com.invalid > > > > > wrote: > > > > > > > You should really take a look at TestStream and have runners > integrate > > > with > > > > it instead. > > > > > > > > There are already several tests which validate TestStream compatible > > > > runners to make sure their trigger evaluations are correct. > > > > > > > > On Wed, Jun 7, 2017 at 10:10 AM, Shen Li <cs.she...@gmail.com> > wrote: > > > > > > > > > Hi Lukasz, > > > > > > > > > > Thanks for the suggestion. I am trying to test how the runner > > generates > > > > > watermarks. So I would like to have the trigger to fire on every > > > > watermark > > > > > advancing event. > > > > > > > > > > Shen > > > > > > > > > > On Wed, Jun 7, 2017 at 10:49 AM, Lukasz Cwik > > <lc...@google.com.invalid > > > > > > > > > wrote: > > > > > > > > > > > Look into the AfterPane#elementCountAtLeast trigger as it seems > to > > be > > > > the > > > > > > closest to your description. It fires as soon as any data is > > > available. > > > > > > > > > > > > Are you sure you don't want some kind of watermark based trigger > > with > > > > > just > > > > > > with a small interval size? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Wed, Jun 7, 2017 at 8:22 AM, Shen Li <cs.she...@gmail.com> > > wrote: > > > > > > > > > > > > > Hi Lukasz, > > > > > > > > > > > > > > Thanks for your response. Is it possible to implement the > > following > > > > > logic > > > > > > > using existing triggers: always fire the trigger on a > > GlobalWindow > > > > > > whenever > > > > > > > watermark advances? > > > > > > > > > > > > > > Shen > > > > > > > > > > > > > > On Wed, Jun 7, 2017 at 10:05 AM, Lukasz Cwik > > > > <lc...@google.com.invalid > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > > Users are unable to create custom trigger implementations. If > > you > > > > > tell > > > > > > us > > > > > > > > what you want your trigger to do, we may be able to suggest > an > > > > > > > alternative. > > > > > > > > > > > > > > > > On Wed, Jun 7, 2017 at 7:41 AM, Shen Li <cs.she...@gmail.com > > > > > > wrote: > > > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > > > I created a custom trigger class (XYZ) by extending the > > > > > OnceTrigger. > > > > > > > > During > > > > > > > > > execution, I got this error "Cannot translate trigger class > > XYZ > > > > to > > > > > a > > > > > > > > > runner-API proto." It seems that the > Triggers.ProtoConverter > > > > class > > > > > > > needs > > > > > > > > to > > > > > > > > > declare a convertSpecific method for my trigger XYZ. How > can > > I > > > > use > > > > > my > > > > > > > > > custom trigger without modifying Beam's Triggers class? > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > > > > > Shen > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
