Is it actually necessary for a PTransform that is configured via the Schema mechanism to also be one that uses RowCoder? Those strike me as two separate concerns and unnecessarily limiting.
On Tue, May 30, 2023 at 1:29 PM Chamikara Jayalath <chamik...@google.com> wrote: > +1 for the simplification. > > On Tue, May 30, 2023 at 12:33 PM Robert Bradshaw <rober...@google.com> > wrote: > >> Yeah. Essentially one needs do (1) name the arguments and (2) implement >> the transform. Hopefully (1) could be done in a concise way that allows for >> easy consumption from both Java and cross-language. >> > > +1 but I think the hard part today is to convert existing PTransforms to > be schema-aware transform compatible (for example, change input/output > types and make sure parameters take Beam Schema compatible types). But this > makes sense for new transforms. > > > >> On Tue, May 30, 2023 at 12:25 PM Byron Ellis <byronel...@google.com> >> wrote: >> >>> Or perhaps the other way around? If you have a Schema we can >>> auto-generate the associated builder on the PTransform? Either way, more >>> DRY. >>> >>> On Tue, May 30, 2023 at 10:59 AM Robert Bradshaw via dev < >>> dev@beam.apache.org> wrote: >>> >>>> +1 to this simplification, it's a historical artifact that provides no >>>> value. >>>> >>>> I would love it if we also looked into ways to auto-generate the >>>> SchemaTransformProvider (e.g. via introspection if a transform takes a >>>> small number of arguments, or uses the standard builder pattern...), >>>> ideally with something as simple as adding a decorator to the PTransform >>>> itself. >>>> >>>> >>>> On Tue, May 30, 2023 at 7:42 AM Ahmed Abualsaud via dev < >>>> dev@beam.apache.org> wrote: >>>> >>>>> Hey everyone, >>>>> >>>>> I was looking at how we use SchemaTransforms in our expansion service. >>>>> From what I see, there may be a redundant step in developing >>>>> SchemaTransforms. Currently, we have 3 pieces: >>>>> - SchemaTransformProvider [1] >>>>> - A configuration object >>>>> - SchemaTransform [2] >>>>> >>>>> The API is generally used like this: >>>>> 1. The SchemaTransformProvider takes a configuration object and >>>>> returns a SchemaTransform >>>>> 2. The SchemaTransform is used to build a PTransform according to the >>>>> configuration >>>>> >>>>> In these steps, the SchemaTransform class seems unnecessary. We can >>>>> combine the two steps if we have SchemaTransformProvider return the >>>>> PTransform directly. >>>>> >>>>> We can then remove the SchemaTransform class as it will be obsolete. >>>>> This should be safe to do; the only place it's used in our API is here >>>>> [3], >>>>> and that can be simplified if we make this change (we'd just trim ` >>>>> .buildTransform()` off the end as `provider.from(configRow)` will >>>>> directly return the PTransform). >>>>> >>>>> I'd like to first mention that I was not involved in the design >>>>> process of this API so I may be missing some information on why it was set >>>>> up this way. >>>>> >>>>> A few developers already raised questions about how there's seemingly >>>>> unnecessary boilerplate involved in making a Java transform portable. I >>>>> wasn't involved in the design process of this API so I may be missing some >>>>> information, but my assumption is this was designed to follow the pattern >>>>> of the previous iteration of this API (SchemaIO): SchemaIOProvider[4] -> >>>>> SchemaIO[5] -> PTransform. However, with the newer >>>>> SchemaTransformProvider API, we dropped a few methods and reduced the >>>>> SchemaTransform class to have a generic buildTransform() method. See the >>>>> example of PubsubReadSchemaTransformProvider [6], where the >>>>> SchemaTransform interface and buildTransform method are implemented >>>>> just to satisfy the requirement that SchemaTransformProvider::from >>>>> return a SchemaTransform. >>>>> >>>>> I'm bringing this up because if we are looking to encourage >>>>> contribution to cross-language use cases, we should make it simpler and >>>>> less convoluted to develop portable transforms. >>>>> >>>>> There are a number of SchemaTransforms already developed, but applying >>>>> these changes to them should be straightforward. If people think this is a >>>>> good idea, I can open a PR and implement them. >>>>> >>>>> Best, >>>>> Ahmed >>>>> >>>>> [1] >>>>> https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/transforms/SchemaTransformProvider.java >>>>> [2] >>>>> https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/transforms/SchemaTransform.java >>>>> [3] >>>>> https://github.com/apache/beam/blob/d7ded3f07064919c202c81a2c786910e20a834f9/sdks/java/expansion-service/src/main/java/org/apache/beam/sdk/expansion/service/ExpansionServiceSchemaTransformProvider.java#L138 >>>>> [4] >>>>> https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/io/SchemaIOProvider.java >>>>> [5] >>>>> https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/io/SchemaIO.java >>>>> [6] >>>>> https://github.com/apache/beam/blob/ed1a297904d5f5c743a6aca1a7648e3fb8f02e18/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/pubsub/PubsubReadSchemaTransformProvider.java#L133-L137 >>>>> >>>>
