[ plotting ] Empty plots are possible

[kamaev]

Moira renders metric plots with every notification (if delivery channel supports this). However, from time to time we see empty images in notifications. Empty images can be caused by bugs in our code or by incorrect or non-existent data in metric storage. Bugs must be fixed, and in case of incorrect or non-existent data we should not send an image at all.

Steps to fix:

• Do not use buff.bytes() for NotificationPackage when Render() fails, use []byte{} instead.
• [limits] Validate ranges by using math.IsInf.
• [limits/resolveLimits] Remove or refactor MinAndMaxOfTime to provide valid and different from/to's.
• Add tests for different retention intervals.

[borovskyav]

metric.txt Metric with 10s retention interval (default is 60s) on which we reproduced "infinite {x,y}-range delta" error bug.

[kamaev]

Main goal is to avoid errors like infinite {x,y}-range delta from wcharczuk/go-chart

[gane5hvarma]

Hi i would like to work on this issue.is anyone working on this?

[beevee]

@gane5hvarma OK, you can take this task.

[dr0pdb]

@beevee I'll be happy to take this one.

[beevee]

@beevee I'll be happy to take this one.

Yeah, sure you can tackle this. But we don't assign tasks to new contributors anymore, since they disappear more often than not. Send us a pull request, and we'll review it.

[hv7214]

@srv-twry are you still on it ? If not, then i picking this up

[dr0pdb]

Sure feel free. I've closed my PR