Connector creation - improve error messaging from server

[peterschretlen]

(Review feedback from docs team on the connectors UI)

#48959 adds a connector creation flyout where you fill a form, and submitting it calls the create action API. We display server-side validation errors, but the messaging is not always clear.

Here are two specific examples:

Example 1: webhook

Example 2: email

1. Is there a way to make these messages easier to read/understand to the user? Both are very
   verbose, and the problem is not made clear.

   • In the case of the email action, erhaps this validation could be done client-side.
   • For the webhook action, could we link to xpack.actions.whitelistedHosts documentation about the whitelisting setting (this page)?

2. All the error messages should start with capital E - "Error validating..."

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[mikecote]

Moving from 7.12 - Candidates to 7.x - Candidates.

[mikecote]

Moving from 7.x - Candidates to 8.x - Candidates (Backlog) after the latest 7.x planning session.

[pmuellr]

The messages from config-schema can get overly wordy. We're really in need of a better solution for JS data validation, as config-schema is only intended for validating Kibana config values into TS-typed objects. It has a number of downsides including the types generated are read-only, so can't be reused for cases where we want construct data of the same shape to pass somewhere else (eg, tests). It also can cause issues if the validated objects are re-validated - durations turn into objects which when passed through the same validation again will fail.

I don't think there's much use in trying to "fix" anything here - except perhaps extremely annoying messages that we see frequently - since we really need to replace what we're using. For those extremely annoying messages, we can provide custom validate methods which produce nicer messages than config-schema does.

Leaving this open though, as I suspect we may get questions about the error messages in the future, and can point them here.

[mikecote]

Closing as no longer relevant.