[BEAM-12453]: Add interface to access I/O topic information for a Samza Beam job and PipelineJsonRenderer to create the JSON Beam DAG

[PawasChhokra]

New Features:

1. This PR creates an interface inside Samza Beam Runner to get I/O information for a Samza Beam job.
2. It also adds a PipelineJsonRenderer which renders the Beam DAG in JSON form.

Uses:

1. The SamzaIOInfo interface can be implemented to emit I/O information of a Samza job. This is used by the PipelineJsonRenderer to add I/O information to the Beam DAG.
2. The JSON renderer helps emit the Beam DAG in JSON form as a config.

These changes can be used in the visualization of the Beam pipeline.

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ValidatesRunner compliance status (on master branch)

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---			---		---
Java
Python	---			---		---
XLang				---		---

Examples testing status on various runners

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---	---	---	---	---	---	---
Java	---		---	---	---	---	---
Python	---	---	---	---	---	---	---
XLang	---	---	---	---	---	---	---

Post-Commit SDK/Transform Integration Tests Status (on master branch)

Go	Java	Python

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website	Whitespace	Typescript
Non-portable
Portable	---			---	---	---

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GitHub Actions Tests Status (on master branch)

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[kw2542]

Run Java PreCommit

[kw2542]

Please fix the compilation error as well:

16:33:00 > Task :runners:samza:compileJava
16:33:00 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_Java_Commit@2/src/runners/samza/src/main/java/org/apache/beam/runners/samza/renderer/PipelineJsonRenderer.java:52: error: [return.type.incompatible] incompatible types in return.
16:33:00 return null;
16:33:00 ^
16:33:00 type of expression: null (NullType)
16:33:00 method return type: @Initialized @NonNull String
16:33:00 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_Java_Commit@2/src/runners/samza/src/main/java/org/apache/beam/runners/samza/renderer/PipelineJsonRenderer.java:74: error: [dereference.of.nullable] dereference of possibly-null reference node.getTransform()
16:33:00 escapeString(fullName.isEmpty() ? OUTERMOST_NODE : node.getTransform().getName()));
16:33:00 ^
16:33:00 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_Java_Commit@2/src/runners/samza/src/main/java/org/apache/beam/runners/samza/renderer/PipelineJsonRenderer.java:103: error: [dereference.of.nullable] dereference of possibly-null reference node.getTransform()
16:33:00 writeLine(" \"shortName\":\"%s\",", escapeString(node.getTransform().getName()));
16:33:00 ^
16:33:00 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_Java_Commit@2/src/runners/samza/src/main/java/org/apache/beam/runners/samza/renderer/PipelineJsonRenderer.java:116: error: [dereference.of.nullable] dereference of possibly-null reference node.getTransform()
16:33:00 if (node.getTransform().getAdditionalInputs().containsKey(key)) {

[aaltay]

What is the next step on this PR?

[kw2542]

LGTM

[xinyuiscool]

LGTM! Thanks for the enhancements.