[TBD] - Implement Docker support with image creation and configuration updates

[novatechflow]

TBD - to be discussed

Summary

Add Docker image support for Apache Wayang without bundling external execution platforms.

Changes

• Add a Dockerfile that packages the Wayang assembly with a Java 17 runtime
• Add a Docker workflow that builds the assembly, builds the image, and runs a Java platform smoke test
• Make SPARK_HOME, HADOOP_HOME, and FLINK_HOME optional in wayang-submit
• Support external platform runtimes through mounted directories and environment variables
• Make Hadoop-backed Java channel conversions conditional on Hadoop classes being available
• Document Docker build and runtime examples in wayang-assembly/README.md

Rationale

The image should distribute Wayang only. Spark, Hadoop, Flink, JDBC drivers, and other platform runtimes remain user supplied so the project does not take ownership of maintaining third-party platform distributions inside the image.

Verification

• bash -n bin/wayang-submit
• JAVA_HOME=/Library/Java/JavaVirtualMachines/zulu-17.jdk/Contents/Home ./mvnw -pl :wayang-java,:wayang-assembly -am -Pdistribution -DskipTests package
• JAVA_HOME=/Library/Java/JavaVirtualMachines/zulu-17.jdk/Contents/Home OTHER_FLAGS=-Duser.home=/private/tmp wayang-assembly/target/apache-wayang-assembly-1.1.2-SNAPSHOT-dist/wayang-1.1.2-SNAPSHOT/bin/wayang-submit org.apache.wayang.apps.pi.PiEstimation java 1

Notes

Built on Mac, path are different on Linux / Windows.

[zkaoudi]

Thanks for bringing the conversation here Alex.
So this is for creating a lightweight standalone Wayang image that could only run jobs in Java. Is that correct?