Afaik, there’s no other resource about using Scala in Flink except the documentation & the blog - https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/scala_api_extensions.html https://flink.apache.org/blog/
If you want something only for scala - https://scala-lang.org/documentation/learn.html. First two are kind of “essential”.
Also you could check Fabian Hueske’s book that will be released later this year - https://www.amazon.com/Stream-Processing-Apache-Flink-Implementation/dp/149197429X/ref=sr_1_1?ie=UTF8&qid=1525865019&sr=8-1&keywords=flink (there is some free chapters in Safari books)
From: Esa Heikkinen <esa.heikkinen@xxxxxxxxxxxxxx>
Sent: Wednesday, May 9, 2018 2:19:01 PM
Subject: Recommended books
Could you recommend some Flink books to learn Scala programming and basics in Flink ?