Adding error box when target not loaded

[harsh-ps-2003]

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Fixes #6876
Added an error box to be shown when the target is loading in Query component.

Verification

Tested in containerised development environment.

[harsh-ps-2003]

Hey @GiedriusS!
Can you check this PR please, I dont know how to delay the targets loading, so I tested in extreme scenarios, when targets are non loaded, then the error came and when the targets are loaded, the error was not coming. But I was not able to check when the target is facing delay in loading so it first shows error message and then when the target gets loaded, the error goes away. If the PR logic is fine, I will fix the checks and add changelogs!

[GiedriusS]

Thanks for this work! I double-checked and it seems like the root problem is that https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L115C42-L115C50 here in case there are any warnings then we don't show them. Prometheus API has no such field "warnings" in the returned response so the component doesn't show that? Here https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L116 we need to capture the warning and then show it in the ScrapePoolListProps.

[harsh-ps-2003]

Thanks for this work! I double-checked and it seems like the root problem is that https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L115C42-L115C50 here in case there are any warnings then we don't show them. Prometheus API has no such field "warnings" in the returned response so the component doesn't show that? Here https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L116 we need to capture the warning and then show it in the ScrapePoolListProps.

So the we need to somehow get hold of the warnings from the response, and present it in the UI in form of error boxes. Okay! I am closing this PR as the changes I did are different. If I am able to solve it, I will open another one! Thanks

[harsh-ps-2003]

Thanks for this work! I double-checked and it seems like the root problem is that https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L115C42-L115C50 here in case there are any warnings then we don't show them. Prometheus API has no such field "warnings" in the returned response so the component doesn't show that? Here https://github.com/thanos-io/thanos/blob/main/pkg/ui/react-app/src/pages/targets/ScrapePoolList.tsx#L116 we need to capture the warning and then show it in the ScrapePoolListProps.

Actually I think there is a warnings field in the response of Prometheus API see. I am working on it!