I'm in favor of this, but I think we need to make it easier to implement data generators and test sources. As things stand in 1.15, unless you can be satisfied with using a NumberSequenceSource followed by a map, things get quite complicated. I looked into reworking the data generators used in the training exercises, and got discouraged by the amount of work involved. (The sources used in the training want to be unbounded, and need watermarking in the sources, which means that using NumberSequenceSource isn't an option.)
I think the proposed deprecation will be better received if it can be accompanied by something that makes implementing a simple Source easier than it is now. People are continuing to implement new SourceFunctions because the interfaces defined by FLIP-27 are hard to understand, while SourceFunction is easy. Alex, I believe you were looking into implementing an easier-to-use building block that could be used in situations like this. Can we get something like that in place first? David On Fri, Jun 3, 2022 at 4:52 PM Jing Ge <j...@ververica.com> wrote: > Hi, > > Thanks Alex for driving this! > > +1 To give the Flink developers, especially Connector developers the clear > signal that the new Source API is recommended according to FLIP-27, we > should mark them as deprecated. > > There are some open questions to discuss: > > 1. Do we need to mark all subinterfaces/subclasses as deprecated? e.g. > FromElementsFunction, etc. there are many. What are the replacements? > 2. Do we need to mark all subclasses that have replacement as deprecated? > e.g. ExternallyInducedSource whose replacement class, if I am not mistaken, > ExternallyInducedSourceReader is @Experimental > 3. Do we need to mark all related test utility classes as deprecated? > > I think it might make sense to create an umbrella ticket to cover all of > these with the following process: > > 1. Mark SourceFunction as deprecated asap. > 2. Mark subinterfaces and subclasses as deprecated, if there are graduated > replacements. Good example is that KafkaSource replaced KafkaConsumer which > has been marked as deprecated. > 3. Do not mark subinterfaces and subclasses as deprecated, if replacement > classes are still experimental, check if it is time to graduate them. After > graduation, go to step 2. It might take a while for graduation. > 4. Do not mark subinterfaces and subclasses as deprecated, if the > replacement classes are experimental and are too young to graduate. We have > to wait. But in this case we could create new tickets under the umbrella > ticket. > 5. Do not mark subinterfaces and subclasses as deprecated, if there is no > replacement at all. We have to create new tickets and wait until the new > implementation has been done and graduated. It will take a longer time, > roughly 1,5 years. > 6. For test classes, we could follow the same rule. But I think for some > cases, we could consider doing the replacement directly without going > through the deprecation phase. > > When we look back on all of these, we can realize it is a big epic (even > bigger than an epic). It needs someone to drive it and keep focus on it > continuously with support from the community and push the development > towards the new Source API of FLIP-27. > > If we could have consensus for this, Alex and I could create the umbrella > ticket to kick it off. > > Best regards, > Jing > > > On Fri, Jun 3, 2022 at 3:54 PM Alexander Fedulov <alexan...@ververica.com> > wrote: > > > Hi everyone, > > > > I would like to start the discussion about marking SourceFunction-based > > interfaces as deprecated. With the FLIP-27 APIs becoming the new > standard, > > the old ones have to be eventually phased out. Although this state is > well > > known within the community and no new connectors based on the old > > interfaces can be accepted into the project, the footprint of > > SourceFunction in the user code still keeps growing (primarily for data > > generators and test utilities). I believe it is best to mark > SourceFunction > > as deprecated as soon as possible. What do you think? > > > > Best, > > Alexander Fedulov > > >
