Hi, Often I encounter a pattern: one gets a big data item, uses some part of it as key, another as value. Thus I've created simple helper PTransform: https://gist.github.com/orian/265e5494e61de931bbfa885ac60eb539
This allows me to reuse given function in manu places, sometimes as key producer and another time as value producer. The usage is super simple: PCollection<KV<String, String>> out = input.apply( MakeKV.of(new SimpleFn(), new Simple2Fn())); In abstract it takes PCollection<V> and returns PCollection<KV<K,V1>>., BTW I had problems with: Cannot provide a Coder for type variable T because the actual type is unknown due to erasure I've found: 1. http://stackoverflow.com/questions/32591914/making-transformations-in-dataflow-generic 2. http://stackoverflow.com/questions/32591914/making-transformations-in-dataflow-generic but neither really made it easy to fix (I've been testing the MakeKV with built in Integer type/coder). I've found a solution in WithKeys.java in SDK. Hope it helps someone. Cheers, Pawel
