METRON-954: Create ability to change output topic of parsers from the CLI

[cestella]

Contributor Comments

Right now, changing the output of the kafka topic for the parsers involves either adjusting source code or adjusting parser configs in zookeeper. It seems sensible to add the output topic to the CLI params as a convenience approach.

To test this,

• Create a topic called my_topic in kafka
• start up a parser topology of your choosing with -ot my_topic
• feed data into it
• use the console consumer to validate output is being piped into my_topic

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[ottobackwards]

Casey, what is the use case for this? Testing?

[cestella]

Yep, testing being a main one. YOu want to try out a parser without having it shove its data into enrichment

[ottobackwards]

Is this required? Could we write a test just for testing the setting?

[cestella]

We could spin up a new integration test, but I thought this did the trick and didn't add the cost of another integration test to the build time.

I do have a test ensuring the value gets passed through to the parser. This just completed the loop. If we don't feel that an integration test is necessary here, then I can remove it too.

Thoughts?

[ottobackwards]

I have a couple of things that come to mind, not all relevant:

• With 777 and 942, squid is a real parser extension, installed and usable etc. So throwing in a test of something outside the parser into it's integration test, and making it diffferent than the others seems not right to me.

• Same for any parser really. The parsers tests are for testing the parsers. You guys did a lot of work making the tests alike, and understandable, we should maintain that.

• If you don't change that, I don't think I'll have to do conflict work in 777, which I continue to have to maintain ;) ( disregard this )

[cestella]

haha ok, you got it. I'll adjust it tomorrow to be a different type of test and not piggyback on squid. You're right, the parser tests are for testing the parsers, not testing the ancillary stuff, like kafka writers. Thanks for keeping me honest, @ottobackwards

[justinleet]

I'm +1. Thanks for adding this. @ottobackwards You need to see anything on this PR?

[ottobackwards]

+1 on inspection, thanks for the contribution

[merrimanr]

Can we add this option to the README?