Bringing Vega out of experimental

[timroes]

We have introduced Vega visualizations in Kibana 6.2 as experimental visualizations and this issue tracks our current status about bringing them out of experimental.

Technical Issues

There are a couple of technical issues, that should be solved before Vega can leave experimental:

• Write more tests
  Vega needs to have a higher tests coverage. We don't need (or want) to test any Vega internal features, but we should functional test everything that we integrated into Vega, e.g. time ranges, filters (in both directions), the editor, embedding Vega, using Vega in reporting, etc.
  • [Vega] add functional tests for Vega visualization #74097
  • **Also, re-enable existing tests: Re-enable vega test: chart should have some initial vega spec text #20131
• Integration with KQL/Kuery (see KQL/Kuery support for TSVB, timelion and Vega visualizations #17722)
  Vega should properly integrate with Kuery/KQL as a query syntax besides Lucene. More information can be found in the above issue.
• Migrate to version 4 of Vega ([Vega] Update to most recent version (4.2 at least) #22644)
  This may fix several bugs in the list below
• Critical bugs fixed
  • Vega visualizations does not appear on PDF export
  • Using item in tooltip causes infinite loop in Vega graphs - may be fixed by version upgrade
  • Incorrect tooltip positioning in dashboards Vega tooltip positioning is broken on dashboards #25363
  • ?
• Dark theme support (Vega vis needs to have visible fonts for dark theme dashboard #16456)
• Localization support
  The main issue is number and date formatting. Vega supports this, but we need to pass in the locale information.

Roadmap

We currently have no plans of removing Vega in any future Kibana version. Within the limits of our capacities we want to move forward with it, and bring it out of experimental at some point in the future, given the technical issues are solved and we have proper capacity to maintain and support it.

Nice to have for GA or may be done after

• Switch options panel to React
• All open bugs closed
  We should close as many bugs we can, since we don't want to pull in new features (as GA), that we know are buggy.
• Move the rest of the code to TS. This partially takes care of this.
• Convert vega tests to jest. This PR addresses this.
• Add inspector to vega vis. Implementation has started here.
• Improve the Vega documentation with more examples. This PR already takes care of this.
• Document the new debugging features of the Vega inspector [Vega][Inspect panel] Write tutorials and reference #73262
• Discuss the severity of the bugs about Vega's filter bar which is not usable with non default index pattern (Vega's filter bar is not usable with non default index pattern #62122, Vega add filter integration errors with non-default index pattern #56833, Improve experience on dashboard when visualizations do not use index patterns created in Kibana #19408)

[dkolas]

I'm a very excited user of the Vega support, and wanted to comment to voice support of its permanence.

We have a workflow with data in elastic where we connect to a Jupyter notebook and model data / develop analytics. These analytics frequently require a semi-custom visualization, for which Altair and Vega fit nicely. The ability to then bring the Vega specifications over and deploy in Kibana is very powerful.

Thanks!

[AlonaNadler]

The team has done great work on Vega in the past few months.
How are we feeling about changing the label to GA?

cc: @timductive