lostluck commented on a change in pull request #12024: URL: https://github.com/apache/beam/pull/12024#discussion_r442603782
########## File path: learning/katas/go/Core Transforms/Side Input/Side Input/pkg/task/task.go ########## @@ -0,0 +1,45 @@ +// Licensed to the Apache Software Foundation (ASF) under one or more +// contributor license agreements. See the NOTICE file distributed with +// this work for additional information regarding copyright ownership. +// The ASF licenses this file to You under the Apache License, Version 2.0 +// (the "License"); you may not use this file except in compliance with +// the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package task + +import ( + "github.com/apache/beam/sdks/go/pkg/beam" +) + +type Person struct { + Name, City, Country string +} + +func ApplyTransform(s beam.Scope, personsKV beam.PCollection, citiesToCountries beam.PCollection) beam.PCollection { + citiesToCountriesView := beam.SideInput{ + Input: citiesToCountries, + } + return beam.ParDo(s, joinFn, personsKV, citiesToCountriesView) +} + +func joinFn(person Person, citiesToCountriesIter func(*string, *string) bool, emit func(Person)) { + var city, country string + for citiesToCountriesIter(&city, &country) { Review comment: Good question! No. It's a valid way to iterate through KV PCollections as Side inputs. Eg. You know your set of KVs is short, but dynamic, and you'll need all of them at random while processing a DoFn. Ideally we also have an alternate Map/Get style random access to KV side inputs as well, but it would be in addition to the existing way. With generics for Go taking their [next steps](https://blog.golang.org/generics-next-step), maybe next year we could bolster the iteration API with any official Iteration format, in addition to the current methods. Edit: There's also the ordinary PCollection<V> approach, which wouldn't be KVs, which would also demonstrate Side input iteration. Side inputs iterators don't have to be KVs. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
