[Fleet][EPM] - Do cache || saved_object || network in http handler (#85331)

## Summary

1. cf0d567 - Export function which maps file path to saved object id
2. e33d7d4 - "make it work" ™️ quality version of "use cached or saved object or registry" file in HTTP handler. It's doing too much and should eventually move the logic to service method(s).

x-pack/plugins/fleet/server/routes/epm/handlers.ts

@@ -17,6 +17,7 @@ import {
   BulkInstallPackageInfo,
   BulkInstallPackagesResponse,
   IBulkInstallPackageHTTPError,
+  ASSETS_SAVED_OBJECT_TYPE,
 } from '../../../common';
 import {
   GetCategoriesRequestSchema,
@@ -41,12 +42,13 @@ import {
   removeInstallation,
   getLimitedPackages,
   getInstallationObject,
+  getInstallation,
 } from '../../services/epm/packages';
 import { defaultIngestErrorHandler, ingestErrorToResponseOptions } from '../../errors';
 import { splitPkgKey } from '../../services/epm/registry';
 import { licenseService } from '../../services';
 import { getArchiveEntry } from '../../services/epm/archive/cache';
-import { bufferToStream } from '../../services/epm/streams';
+import { PackageAsset, assetPathToObjectId } from '../../services/epm/archive/save_to_es';
 
 export const getCategoriesHandler: RequestHandler<
   undefined,
@@ -107,32 +109,46 @@ export const getFileHandler: RequestHandler<TypeOf<typeof GetFileRequestSchema.p
   try {
     const { pkgName, pkgVersion, filePath } = request.params;
     const savedObjectsClient = context.core.savedObjects.client;
-    const savedObject = await getInstallationObject({ savedObjectsClient, pkgName });
-    const pkgInstallSource = savedObject?.attributes.install_source;
-    // TODO: when package storage is available, remove installSource check and check cache and storage, remove registry call
-    if (pkgInstallSource === 'upload' && pkgVersion === savedObject?.attributes.version) {
-      const headerContentType = mime.contentType(path.extname(filePath));
+    const installation = await getInstallation({ savedObjectsClient, pkgName });
+    const useLocalFile = pkgVersion === installation?.version;
+
+    if (useLocalFile) {
+      const archiveKey = `${pkgName}-${pkgVersion}/${filePath}`;
+      const archiveEntry = getArchiveEntry(archiveKey);
+      const assetSavedObject = await savedObjectsClient.get<PackageAsset>(
+        ASSETS_SAVED_OBJECT_TYPE,
+        assetPathToObjectId(archiveKey)
+      );
+
+      if (!archiveEntry && !assetSavedObject) {
+        return response.custom({
+          body: `installed package file not found: ${filePath}`,
+          statusCode: 404,
+        });
+      }
+
+      const headerContentType =
+        assetSavedObject.attributes.media_type || mime.contentType(path.extname(archiveKey));
       if (!headerContentType) {
         return response.custom({
           body: `unknown content type for file: ${filePath}`,
           statusCode: 400,
         });
       }
-      const archiveFile = getArchiveEntry(`${pkgName}-${pkgVersion}/${filePath}`);
-      if (!archiveFile) {
-        return response.custom({
-          body: `uploaded package file not found: ${filePath}`,
-          statusCode: 404,
-        });
-      }
-      const headers: ResponseHeaders = {
-        'cache-control': 'max-age=10, public',
-        'content-type': headerContentType,
-      };
+
+      const { data_base64: base64, data_utf8: utf8 } = assetSavedObject.attributes;
+      // if we have a local Buffer, use that
+      // else, create one from the saved object (try utf8 first)
+      const responseBody =
+        archiveEntry || utf8 ? Buffer.from(utf8, 'utf8') : Buffer.from(base64, 'base64');
+
       return response.custom({
-        body: bufferToStream(archiveFile),
+        body: responseBody,
         statusCode: 200,
-        headers,
+        headers: {
+          'cache-control': 'max-age=10, public',
+          'content-type': headerContentType,
+        },
       });
     } else {
       const registryResponse = await getFile(`/package/${pkgName}/${pkgVersion}/${filePath}`);

x-pack/plugins/fleet/server/services/epm/archive/save_to_es.ts

@@ -17,10 +17,6 @@ import {
 } from '../../../../common';
 import { getArchiveEntry } from './index';
 
-// uuid v5 requires a SHA-1 UUID as a namespace
-// used to ensure same input produces the same id
-const ID_NAMESPACE = '71403015-cdd5-404b-a5da-6c43f35cad84';
-
 // could be anything, picked this from https://github.com/elastic/elastic-agent-client/issues/17
 const MAX_ES_ASSET_BYTES = 4 * 1024 * 1024;
 
@@ -34,6 +30,12 @@ export interface PackageAsset {
   data_base64: string;
 }
 
+export function assetPathToObjectId(assetPath: string): string {
+  // uuid v5 requires a SHA-1 UUID as a namespace
+  // used to ensure same input produces the same id
+  return uuidv5(assetPath, '71403015-cdd5-404b-a5da-6c43f35cad84');
+}
+
 export async function archiveEntryToESDocument(opts: {
   path: string;
   buffer: Buffer;
@@ -114,7 +116,7 @@ export async function archiveEntryToBulkCreateObject(opts: {
   const { path, buffer, name, version, installSource } = opts;
   const doc = await archiveEntryToESDocument({ path, buffer, name, version, installSource });
   return {
-    id: uuidv5(doc.asset_path, ID_NAMESPACE),
+    id: assetPathToObjectId(doc.asset_path),
     type: ASSETS_SAVED_OBJECT_TYPE,
     attributes: doc,
   };