Linkerd2: Add a "No Info Found" label to tables in dashboard if they are empty

[scottcarol]

Feature Request

What problem are you trying to solve?

Currently when a table in the dashboard has no rows to display, it shows just the title and column titles. This could be confusing since it's not clear if something's gone wrong or if there is just no data found for that topic.

How should the problem be solved?

Display a friendly message like "No inbound resources found" or "No edges found" somewhere on each table if empty.

cc @grampelberg

[klingerf]

Alternatively, we might want to consider omitting the Edges table altogether if there's no edge info. That's more consistent with how we handle the Inbound and Outbound tables on this page. But I could also see the value in displaying a "no edges" message if it would help the user understand why there's no edge data.

[scottcarol]

@klingerf The original dashboard behavior for the Edges table was to omit it altogether if no edges were found, but my current PR #2995 changes this, after @grampelberg made the point that "No edges found" is also valuable information and worth pointing out explicitly.

Currently we still display Inbound/Outbound tables even if they are empty - see blank table for Outbound below taken from localhost:7777/namespaces/linkerd/pods/linkerd-prometheus-fd4dcc6fd-cs82g

[klingerf]

@scottcarol Ahhhh, sorry, I was mistaken. Am not sure where I got the idea that we were omitting those tables. Ok, this all makes sense to me. Thanks for the explanation!

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[scottcarol]

I still think this could be a good improvement!

[grampelberg]

I've got a POC empty state table in the mockups =)

[scottcarol]

Closed in favor of #3611