added offline replicas operation to client for kafka version >= 1.x

[drsoares]

Added Offline Replicas Operation to Client.

• Added OfflineReplicas Operation
• Implemented Operation
• Added unit tests
• Changed the metadata request and response encoders
• Add to add logic to set the version id based on the version present on the Config

#1311

[varun06]

why not return here?

[drsoares]

If the protocol version is higher than 3 (0.11.0.0), which is the case of version 1.0.0.0 (5) that supports the offline replicas request, the if block on the bottom of the function would be skipped:

if r.Version > 3 {
   autoCreation, err := pd.getBool()
   if err != nil {
      return err
   }
   r.AllowAutoTopicCreation = autoCreation
}

But obviously I admit this is a potential point of improvement, I can try to refactor this to a more idiomatic way.

[varun06]

yeah, please have a look, if it's can't be refactored, I am not super against GOTO's

[drsoares]

done

[gbbr]

This breaks the API, so you should probably bump your next major version to 2.x since this technically isn't 1.x anymore.

[varun06]

Apologies for missing it @gbbr
I also had to fix an interface after upgrading to this. I am gonna work with @bai and team to handle breaking changes better in future.

[drsoares]

Can you please clarify where were the breaking changes introduced? Apologies in advance.

[varun06]

OfflineReplicas was a new method in client interface. We have some internal stuff where we implement the interface. So when I ran tests with new version, it was complaining for that method, I implemented it and all fine. But it seems that @gbbr had a breaking build too.

[drsoares]

There was however a breaking change introduced on the testing api, however there's nothing stoping you from using those methods on your code as helpers, perhaps they should be moved into some internal package.

[gbbr]

You've actually motivated me to write this (very experimental) package over the weekend: https://github.com/gbbr/breakcheck

[varun06]

@gbbr that's great, I will have a look and might help with some issues(time permitted).