Add SO import hook / warnings API

[pgayvallet]

Summary

Fix #84977

This PR adds hook support to SO imports. Type owners can now register an import hook using the new SavedObjectType.onImport property when registering their type via registerType.

The import hooks currently only support a single feature: returning import warnings that will be displayed to the user when the import succeeds.

API usage example

public setup(core: CoreSetup, plugins: SetupDeps) {
  core.savedObjects.registerType({
    name: 'my_type',
    hidden: false,
    namespaceType: 'single',
    mappings: { /* [...] */ },
    management: {
        importableAndExportable: true,
        onImport: async (objects) => {
          if(await someActionIsNeeded(objects)) {
            return {
              warnings: [
                { type: 'simple', message: 'Just some basic warning about the import' },
                {
                  type: 'action_required',
                  message: 'Alerts have been imported, but are disabled',
                  actionUrl: '/app/dashboards?foo=bar',
                  buttonLabel: 'Enabled here',
                },
              ],
            };
          }
          return {};
      },
      // [...]
    },
  });

  return {};
}

Screenshots

How to test

I personally used this diff to add warnings to dashboards during testing

Index: src/plugins/dashboard/server/plugin.ts
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/plugins/dashboard/server/plugin.ts b/src/plugins/dashboard/server/plugin.ts
--- a/src/plugins/dashboard/server/plugin.ts	(revision 0ba9aea5f2aa9b7afe885a2bd364610656db8376)
+++ b/src/plugins/dashboard/server/plugin.ts	(date 1610725322281)
@@ -49,13 +49,30 @@
   public setup(core: CoreSetup, plugins: SetupDeps) {
     this.logger.debug('dashboard: Setup');
 
-    core.savedObjects.registerType(
-      createDashboardSavedObjectType({
-        migrationDeps: {
-          embeddable: plugins.embeddable,
+    const dashboardType = createDashboardSavedObjectType({
+      migrationDeps: {
+        embeddable: plugins.embeddable,
+      },
+    });
+    core.savedObjects.registerType({
+      ...dashboardType,
+      management: {
+        ...dashboardType.management,
+        onImport: (dashboards) => {
+          return {
+            warnings: [
+              { type: 'simple', message: 'Just some basic warning about the import' },
+              {
+                type: 'action_required',
+                message: 'Alerts have been imported, but are disabled',
+                actionPath: '/app/dashboards?foo=bar',
+                buttonLabel: 'Enable here',
+              },
+            ],
+          };
         },
-      })
-    );
+      },
+    });
     core.capabilities.registerProvider(capabilitiesProvider);
 
     registerDashboardUsageCollector(plugins.usageCollection, plugins.embeddable);

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[mikecote]

I tested the functionality in the context of alerting's needs and LGTM 👍

[azasypkin]

Changes in Spaces plugin tests LGTM and Copy to Space API/UI can be updated in a follow-up.

[joshdover]

Very little to add here. Follows a similar structure to #87807 so it's quite easy to follow. Let's make sure to track Alerting's and SIEM's integration with this once these two PRs are merged.

[joshdover]

Should we name this actionPath instead of URL to make this more clear that it should be an in-app path and cannot be an external URL?

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 1717c3e

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
savedObjectsManagement	190.6KB	192.9KB	+2.3KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
core	562.3KB	563.6KB	+1.3KB
savedObjectsManagement	72.0KB	72.0KB	+33.0B
total			+1.3KB

History

• 💚 Build #100009 succeeded 6d999f3
• 💚 Build #99874 succeeded 09a4b51
• 💚 Build #99085 succeeded a46740d
• 💔 Build #99052 failed 5e699b1
• 💚 Build #98797 succeeded 85709cb

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@elasticmachine merge upstream