Graph Migration plan

[flash1293]

This issue lays out the legacy dependencies of Graph and in what order to migrate all of the parts over to the new target architecture.

Server side

The Graph server contains two proxies forwarding regular search queries and explore queries to the respective Elasticsearch endpoints and license checking. The license is also checked client side which removes the need to do a separate check on the server side. The search endpoint can be replaced with a call to the low level search service app arch team is currently building. The proxy for explore calls can follow a similar approach as the Lens implementation.

Client side

All dependencies are included in a central app.js file which makes moving to the new platform easy because everything is already passed down from a central point. New components will never import stuff by themselves, but rely on getting all dependencies passed down from app.js.

The following files are currently imported and have to be replaced by their NP counterparts:

Done	Import	interim	👉
✅	ui/directives/saved_object_finder		❌
✅	ui/directives/input_focus		❌
✅	ui/saved_objects/ui/saved_object_save_as_checkbox		❌
	{ addAppRedirectMessageToUrl, fatalError, toastNotifications } from ui/notify	LP	core.notifications
	{ formatAngularHttpError } from ui/notify/lib	LP	core.notifications
✅	{ IndexPatternsProvider } from ui/index_patterns		data.indexPatterns
✅	chrome from ui/chrome		core.chrome
✅	{ capabilities } from ui/capabilities	Global Angular	core.application
	$http	Global Angular	core.http
✅	config		core.uiSettings
	ui/kbn_top_nav	Local Angular	{ TopNavMenu } from '../kibana_react/public' - make part of chrome component after state management is de-angularized
	{ SavedObjectsClientProvider } from ui/saved_objects	Global Angular	? core.saved_objects once saved objects are de-angularized
	uiRoutes from ui/routes	Local Angular	❌react router
	{ uiModules } from ui/modules	Local Angular	❌
	uiExports/fieldFormats	Global Angular	? probably not necessary anymore (might have been transient dependency of index patterns)
	ui/autoload/all	Global Angular	❌
	uiExports/savedObjectTypes	Global Angular	? app arch
	{ SavedObjectRegistryProvider } from ui/saved_objects/saved_object_registry	Global Angular	? app arch #46435
	{ KibanaParsedUrl } from ui/url/kibana_parsed_url	LP	? might be replaced by url service
	{ xpackInfo } from plugins/xpack_main/services/xpack_info	LP	licensing plugin #44922
	kbnUrl	Local Angular	?
	kbnBaseUrl	Global Angular	?
	confirmModal	Global Angular	replace by own implementation and core.overlays
	chrome.getInjected	LP	#47319 npStart.core.injectedMetadata.getInjectedVar
	ui.ace	Local Angular	❌When inspect moved to inspector service
	ui.bootstrap	Local Angular	❌When UI is de-angularized
	{ showSaveModal } from 'ui/saved_objects/show_saved_object_save_modal'	LP	replace by own implementation and core.overlays

The rewrite will be approached in the following order (see #44225 for tracking progress):

• Shim plugin with local angular instance
• Move all data fetching to core.http
• Implement own confirModal
• Migrate saved objects to own implementation
• Move top nav to react
• Typing data fetching
• Typing layouting logic and move out of model
• Redux state handling for the rest
• Move to react router
• Get rid of angular

Reference: https://github.com/elastic/kibana/blob/master/src/core/MIGRATION.md
Approach outline slide deck: https://docs.google.com/presentation/d/1qTQlbcUpNEZRZKxLWVdGLIs85UHIEz2oHt7QPx8qcrk/edit?usp=sharing

[elasticmachine]

Pinging @elastic/kibana-app

[timroes]

Done, Graph is moved completely to Kibana Platform.