Add date to charts in web UI

[kentmartin73]

Prerequisites

• [X] I am using the latest version of Locust
• [X] I am suggesting a new feature, not asking a question

Description

The charts produced by the UI are great for an overview of what happened when, but when doing load and stability tests that run for days, it is very difficult to see which day what happened. Adding the date to the X axis in addition to the time and/or the mouseover information would make the charts a lot easier to read in these circumstances

[cyberw]

I think that sounds like a useful option, maybe even something that could be automatically enabled once the test runs for more than 24. But someone needs to build it :)

[alejandro-carmena]

I would also say that it could be quite useful being able to zoom in on the charts, also for having a better visibility in the tests that run for days.

[andrewbaldwin44]

I think trying to detect when the test runs for more than 24hr to display the date adds too much overhead, not to mention adding the date to the x axis makes it quiet difficult to read. I would suggest displaying keeping the display on the x axis and add the full timestamp to the tooltip (on mouseover) On the frontend it would be straightforward, we would just need to modify the stats and history in the backed to return a UTC timestamp instead of just the current time. What do you think @cyberw?

Also for zooming this is supported in echarts so I will add it :+1:

[cyberw]

Sounds good!

[JavierUhagon]

#2731 was merged, this should be closed, right? @cyberw