Use elastic-charts in Kibana Discover

[emmacunningham]

Is your feature request related to a problem? Please describe.
Additional features needed in elastic-charts:

• DONE BarSeriesSpec needs to have a "histogram mode" for positioning ticks correctly (PR feat: add histogram mode #218)
  
  • ticks should be aligned to the starting edge of a bar and bars cannot be clustered (only stacked)
  • xDomain annotation positions should be aligned correctly (currently they snap to a band edge)
• DONE customizable tooltip content (PR feat(tooltip): add custom headerFormatter #233)
  • need to be able to add x-axis title to chart tooltip (formatter for tooltip header)
  • need to be able to add message about partial bucket to chart tooltip (additional information iff match for filter value)
• DONE in histogram mode, need to extend line annotation (PR fix(line_annotation): use scaleAndValidate for line annotations #236)
• DONE check bucket sizing in histogram mode, at some time intervals, buckets appear much larger (PR feat: add minInterval option for custom xDomain #240)
• DONE ticks in histogram mode need to be extended correctly (PR fix(ticks): fill in additional ticks for histogram #251 )
• DONE single datum tooltip bug (PR fix: position tooltip within chart with single value xScale #259)
• DONE show now line annotation in single datum yearly view (PR fix: adjust domain & range for single value histogram #265)

On the Kibana side:

• IN PROGRESS Use elastic-charts component (Replace Discover chart with elastic-charts kibana#43788)
  • Partial bucket rect annotations
  • Partial bucket custom tooltip header
  • Line annotation for current time
  • Axis ticks line up correctly for each time interval
  • Buckets render correctly for each time interval
    • check all ranges at auto interval
    • check all ranges at manually set intervals
  • On brush, fetch new data
  • styling (we will use the elastic-charts theme defaults but should check both dark & light modes)
  • fix tests [note updating with elastic-charts did not break any tests]
  • line annotation for now renders correctly
    • within chart when now is within time range
    • adjust position to make line visible when at domain edge
  • localize custom text
  • rect annotation tooltip should be formatted correctly
  • y-axis formatter
  • bug when hovering out of tooltip

Describe the solution you'd like
Use elastic-charts for the charts in Kibana Discover.

Describe alternatives you've considered

Additional context

Kibana Cross Issues
TODO

Checklist

• this request is checked against already exist requests
• every related Kibana issue is listed under Kibana Cross Issues list
• kibana cross issue tag is associated to the issue if any kibana cross issue is present

[emmacunningham]

A couple of things to discuss:

• y axis formatter when counts are < 0 (when interval is very low)
• should we write tests for the histogram component?
• yearly view, e.g.:

monthly and weekly views seem to be wrong in current implementation?

[emmacunningham]

Follow-up from elastic-charts sync:

• y axis formatter when counts are < 0 (when interval is very small - milliseconds or seconds)
  the current implementation formats all values below 0 as 0 which is not very useful. the group's consensus is that the elastic-charts handling (rendering the much more detailed decimal values) is the correct one and also that getting to these views is in and of itself odd.

• should we write tests for the histogram component?
  no because there currently are no tests for the component and as things in discover are changing quickly, the effort outweighs the gains. we will write no new additional tests.

• yearly, monthly, and weekly manual intervals:
  the elastic-charts bucket sizes are correct and there appears to be an issue with the current implementation (see above screenshots). as for the yearly view, this is a weird case to begin with (we may want to disable the user's ability to select this for date ranges that are too small). at any rate, the group agreed that the elastics-charts bucket size for these larger ranges is correct and we will follow up on the kibana side to better enforce the interval options.

[markov00]

close as Kibana Discover is already using elastic-charts since 7.5