[EPM] Reduce usage of epm-package SavedObject (#52576)

* Delete existing Installation type. Rename InstallationAttributes to Installation

* Reduce usage of EPM SO. Add getInstallation().

Replaced two calls of getInstallationObject() with getInstallation().

Two less places with knowledge of SO internals.

Lots of potential improvements for EPM TS types remain (refactoring/removing Installable, etc), but this is a good incremental step, IMO

x-pack/legacy/plugins/epm/common/types.ts

@@ -156,16 +156,15 @@ export type PackageListItem = Installable<RegistrySearchResult & PackageAddition
 export type PackagesGroupedByStatus = Record<InstallationStatus, PackageList>;
 export type PackageInfo = Installable<RegistryPackage & PackageAdditions>;
 
-export type Installation = SavedObject<InstallationAttributes>;
-export interface InstallationAttributes extends SavedObjectAttributes {
+export interface Installation extends SavedObjectAttributes {
   installed: AssetReference[];
 }
 
 export type Installable<T> = Installed<T> | NotInstalled<T>;
 
 export type Installed<T = {}> = T & {
   status: InstallationStatus.installed;
-  savedObject: Installation;
+  savedObject: SavedObject<Installation>;
 };
 
 export type NotInstalled<T = {}> = T & {

x-pack/legacy/plugins/epm/server/packages/get.ts

@@ -6,7 +6,7 @@
 
 import { SavedObjectsClientContract } from 'src/core/server/';
 import { SAVED_OBJECT_TYPE_PACKAGES } from '../../common/constants';
-import { Installation, InstallationAttributes, Installed, NotInstalled } from '../../common/types';
+import { Installation, Installed, NotInstalled } from '../../common/types';
 import * as Registry from '../registry';
 import { createInstallableFrom } from './index';
 
@@ -35,7 +35,7 @@ export async function getPackages(
     type: SAVED_OBJECT_TYPE_PACKAGES,
     id: `${name}-${version}`,
   }));
-  const results = await savedObjectsClient.bulkGet<InstallationAttributes>(searchObjects);
+  const results = await savedObjectsClient.bulkGet<Installation>(searchObjects);
   const savedObjects = results.saved_objects.filter(o => !o.error); // ignore errors for now
   const packageList = registryItems
     .map(item =>
@@ -74,13 +74,21 @@ export async function getPackageInfo(options: {
 export async function getInstallationObject(options: {
   savedObjectsClient: SavedObjectsClientContract;
   pkgkey: string;
-}): Promise<Installation | undefined> {
+}) {
   const { savedObjectsClient, pkgkey } = options;
   return savedObjectsClient
-    .get<InstallationAttributes>(SAVED_OBJECT_TYPE_PACKAGES, pkgkey)
+    .get<Installation>(SAVED_OBJECT_TYPE_PACKAGES, pkgkey)
     .catch(e => undefined);
 }
 
+export async function getInstallation(options: {
+  savedObjectsClient: SavedObjectsClientContract;
+  pkgkey: string;
+}) {
+  const savedObject = await getInstallationObject(options);
+  return savedObject?.attributes;
+}
+
 function sortByName(a: { name: string }, b: { name: string }) {
   if (a.name > b.name) {
     return 1;

x-pack/legacy/plugins/epm/server/packages/index.ts

@@ -4,6 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
+import { SavedObject } from '../../../../../../src/core/server';
 import {
   AssetType,
   // ElasticsearchAssetType,
@@ -41,7 +42,10 @@ export class PackageNotInstalledError extends Error {
 // only Kibana Assets use Saved Objects at this point
 export const savedObjectTypes: AssetType[] = Object.values(KibanaAssetType);
 
-export function createInstallableFrom<T>(from: T, savedObject?: Installation): Installable<T> {
+export function createInstallableFrom<T>(
+  from: T,
+  savedObject?: SavedObject<Installation>
+): Installable<T> {
   return savedObject
     ? {
         ...from,

x-pack/legacy/plugins/epm/server/packages/install.ts

@@ -6,11 +6,11 @@
 
 import { SavedObject, SavedObjectsClientContract } from 'src/core/server/';
 import { SAVED_OBJECT_TYPE_PACKAGES } from '../../common/constants';
-import { AssetReference, InstallationAttributes, KibanaAssetType } from '../../common/types';
+import { AssetReference, Installation, KibanaAssetType } from '../../common/types';
 import { installIndexPattern } from '../lib/kibana/index_pattern/install';
 import * as Registry from '../registry';
 import { getObject } from './get_objects';
-import { getInstallationObject } from './index';
+import { getInstallation } from './index';
 
 export async function installPackage(options: {
   savedObjectsClient: SavedObjectsClientContract;
@@ -64,17 +64,17 @@ export async function saveInstallationReferences(options: {
   toSave: AssetReference[];
 }) {
   const { savedObjectsClient, pkgkey, toSave } = options;
-  const savedObject = await getInstallationObject({ savedObjectsClient, pkgkey });
-  const savedRefs = savedObject && savedObject.attributes.installed;
+  const installation = await getInstallation({ savedObjectsClient, pkgkey });
+  const savedRefs = installation?.installed || [];
   const mergeRefsReducer = (current: AssetReference[], pending: AssetReference) => {
     const hasRef = current.find(c => c.id === pending.id && c.type === pending.type);
     if (!hasRef) current.push(pending);
     return current;
   };
 
-  const toInstall = toSave.reduce(mergeRefsReducer, savedRefs || []);
+  const toInstall = toSave.reduce(mergeRefsReducer, savedRefs);
 
-  await savedObjectsClient.create<InstallationAttributes>(
+  await savedObjectsClient.create<Installation>(
     SAVED_OBJECT_TYPE_PACKAGES,
     { installed: toInstall },
     { id: pkgkey, overwrite: true }

x-pack/legacy/plugins/epm/server/packages/remove.ts

@@ -8,16 +8,16 @@ import { SavedObjectsClientContract } from 'src/core/server/';
 import { SAVED_OBJECT_TYPE_PACKAGES } from '../../common/constants';
 import { AssetReference, AssetType, ElasticsearchAssetType } from '../../common/types';
 import { CallESAsCurrentUser } from '../lib/cluster_access';
-import { getInstallationObject, savedObjectTypes } from './index';
+import { getInstallation, savedObjectTypes } from './index';
 
 export async function removeInstallation(options: {
   savedObjectsClient: SavedObjectsClientContract;
   pkgkey: string;
   callCluster: CallESAsCurrentUser;
 }): Promise<AssetReference[]> {
   const { savedObjectsClient, pkgkey, callCluster } = options;
-  const installation = await getInstallationObject({ savedObjectsClient, pkgkey });
-  const installedObjects = (installation && installation.attributes.installed) || [];
+  const installation = await getInstallation({ savedObjectsClient, pkgkey });
+  const installedObjects = installation?.installed || [];
 
   // Delete the manager saved object with references to the asset objects
   // could also update with [] or some other state