nodejs-express: Shut down Kafka clients when HTTP server is closed

[djones6]

This PR illustrates how to avoid a hang when running the stack tests where the application makes connections to external services.

Checklist:

• [x] Read the Code of Conduct and Contributing Guidelines.

• [x] Followed the commit message guidelines.

• [x] Stack adheres to Appsody stack structure.

Modifying an existing stack:

• [x] Updated the stack version in stack.yaml

I have added a callback on the HTTP server close event, to disconnect the Kafka producer and consumer. This allows the process to terminate normally.

Related Issues:

Resolves #831

[djones6]

@gireeshpunathil Do you think this can be merged?

[gireeshpunathil]

@gireeshpunathil Do you think this can be merged?

Yes. @neeraj-laad - for your review

(Ironically, I am a maintainer of the stack, but not a maintainer of this repo)

[Kamran64]

@gireeshpunathil - Usually we wait to see an approval from the stack maintainer before merging. @djones6 - Please could you bump the stack version in the stack.yaml and then we can get this merged. Thanks!

[gireeshpunathil]

@gireeshpunathil - Usually we wait to see an approval from the stack maintainer before looking.

can you pls document this? It is neither evident here, nor an established practice in OSS

[neeraj-laad]

@gireeshpunathil I've added you as a stack maintainers group.

Also the review for maintainers is documents in our contribution process.

[neeraj-laad]

@djones6 please can you bump the stack version so we can merge this?