Add Lag value

[polo-asm]

Describe the bug
I want to have the Lag value updated in real time.

To Reproduce
Show detail on Topics. The detail show all consumer groups.

Expected behavior
The Lag value show '?' currently. Is it possible to have the Lag value updated in real time

version:
Current version 0.0.23

Additional context
WSL on WIndows

[Mcdostone]

Hi,

It's a good idea, I've been wanting this feature but dont' have a lot of time these days. I have to dive into the rdkafka crate to see if I can have access to this information. Feel free to contribute to this project if you can !

And I think we need this PR to be merged to implement this feature:
https://github.com/fede1024/rust-rdkafka/pull/785/changes

[TeCHiScy]

Hi @Mcdostone ,

Thanks for making such a great TUI kafka client.

I've been using ktea some times ealier. It has a seperate tab to show consumer groups, including consumer group name, member count. By entering a consume group's detail, you can see detailed consume status for each partition, including: offset, high water mark and lag. I've attached a screenshot from its repo.

I think it may be useful to have such a consumer group pane / tab with realtime updated lag values, especially if I'm troubleshooting some consume issues (lag) in the cluster.

I can also volunteer to draft a PR on this feature, if it is planned in yozefu's roadmap.

[Mcdostone]

hello @TeCHiScy,

the tab you are referting to already exists I think:

• in the topics panel, select the topic you are interested in
• press ctrl+P

Does it answer your need?

Unfortunately, we can't display the lag of consumers yet because the rdkafka crate doesn't support it.

[TeCHiScy]

hello @TeCHiScy,

the tab you are referting to already exists I think:

• in the topics panel, select the topic you are interested in
• press ctrl+P

Does it answer your need?

Unfortunately, we can't display the lag of consumers yet because the rdkafka crate doesn't support it.

Maybe not. Let me try to explain:

The needs to view consumer groups include 2 usecases:

• I know the topic, and I want to know which consumer group(s) are consuming this topic, and the consume status on each partition of the topic. Take a example like: I want to see consumer groups whose name contain G that are consuming T topic.

  • ✅ I first filter and then select the T topic
  • Use Ctrl+P on T topic, currently:
    • ⚠️ The consumer groups listed ARE NOT filtered by the topic selected (i.e., T).
    • ⚠️ The list in Ctrl+P is not interactive. i.e., I can't filter consumer groups in any manner. With a real consumer group tab or some interactive list, I can further filter G, and to see the consume status.
    • ⚠️ For a consumer group (e.g., G) consumes a topic (e.g., T), I can't see its consume status on each partition, nor the offset/high watermark/lag (for each topic partition).
  • Also, in this usecase, the consumer group status seems to be hidden deeply in some corner (behind Ctrl+P), but it maybe as important as topic records, especially when digging lag issues.

• I know partial name of a consumer group, I want to see which topics it is consuming, and the consume status.

  • ⚠️ Since there's no seperate consumer groups tab / list. There's no way to achieve this requirement.
  • In ktea, I can filter consumer groups in Consumer Groups tab. Then, I can select a group, and see all the topics it is consuming (in a sub left pane), and consume status of each topic / partition (in a sub right pane).

Thanks!