[Logs UI] Strange behavior with minimap, scrolling, and live streaming

[jasonrhodes]

Kibana version:
7.3.0

Original install method (e.g. download page, yum, from source, etc.):
Observability dev test cluster

Describe the bug:
Not entirely sure what's going on here, needs some investigation. When you turn live streaming on in the logs UI, I have a couple questions about what I should be seeing:

1. The status bar at the bottom that says "Streaming new entires / last updated" is only visible when you are scrolled down to the bottom edge (I think that's expected)
2. The interval for when we poll for new logs doesn't seem to be consistent or represented anywhere, sometimes it's a minute, sometimes it goes for several minutes.
3. When an update does happen, I think it brings you back to the bottom? Hard to tell because updates don't happen often enough to verify.
4. If I scroll up through the logs while live streaming is on, what happens when a live stream update happens? I think it should just append the logs to the bottom and leave you where you scrolled to, but it might be recentering you back at the log stream edge.
5. If I click on the minimap while live streaming is on, same question as above. But also, even before a live stream update happens, something weird seems to be happening after I click on the minimap and move UP the page, and then try to scroll, it seems to immediately jump back to the live stream edge, also.

[elasticmachine]

Pinging @elastic/infra-logs-ui

[Titch990]

I've also had some really weird behaviour when live streaming logs the Observability dev test cluster. I can live stream far into the future!

I'm running the 7.x.x.BC cluster.

@jasonrhodes Here's what I did. The behaviour is the same in Chrome and Safari.

1. Logs > Stream live.
2. While live streaming, scroll up through the log entries.
3. Also click somewhere on the minimap
4. Now stop live streaming, then start it again. The log entries shown are for around a day in the future!
5. Repeat the last step. Each time, the log entries advance around a day!

I have a short M4 video, but I can't upload that here as MP4s aren't supported.

[weltenwort]

What I'm wondering is why there are log entries from future days in the cluster 🤔 We might have to tweak the live streaming behavior to better handle time-travel situations.

[Zacqary]

Not seeing the future logs on the 8.x.x cluster, I'll try switching to 7.x.x to see if I can reproduce.

I am seeing the behavior where the live stream kicks you back to the bottom after scrolling, though. From a UX perspective I feel like this makes some sense. When live streaming is turned off, new log entries are loaded when you scroll to the bottom of the log stream; with that paradigm in mind it only makes sense to load additional data if you're looking at that edge of the stream.

So maybe scrolling up should pause live streaming?

@hbharding you want to weigh in on some of the UX questions here?

[Zacqary]

The interval for when we poll for new logs doesn't seem to be consistent or represented anywhere, sometimes it's a minute, sometimes it goes for several minutes.

On the 8.x.x cluster it seems to be 10 seconds. Not sure where that's defined.

[weltenwort]

The requests happen every 5 seconds (see

kibana/x-pack/legacy/plugins/infra/public/components/logging/log_time_controls.tsx

Line 92 in 33c237e

this.props.startLiveStreaming(5000);

). When they return, of course, is a matter of the cluster and network performance.

[Zacqary]

I'm trying to improve this issue by canceling live streaming when the user scrolls up, but there's a problem: if the most recent live stream request still hasn't completed when you stop live streaming, the log stream will be replaced by a loading state.

This also happens if you click the Stop Streaming button.

The loading state is coupled very tightly to GraphQL, and there's no clear way to abort a pending request. Looking into this.