app-backend: added initial db migration for asset cache

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/app-backend/migrations/20211229105307_init.js

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// @ts-check
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.up = async function up(knex) {
+  return knex.schema.createTable('static_asset_cache', table => {
+    table.comment(
+      'A cache of static assets that where previously deployed and may still be lazy-loaded by clients',
+    );
+    table
+      .string('path')
+      .primary()
+      .notNullable()
+      .comment('The path of the file');
+    table
+      .dateTime('last_modified_at')
+      .notNullable()
+      .comment(
+        'Timestamp of when the asset was most recently seen in a deployment',
+      );
+    table.binary('content').notNullable().comment('The asset content');
+  });
+};
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.down = async function down(knex) {
+  return knex.schema.dropTable('static_asset_cache');
+};

plugins/app-backend/package.json

@@ -39,6 +39,7 @@
     "express-promise-router": "^4.1.0",
     "fs-extra": "9.1.0",
     "helmet": "^4.0.0",
+    "knex": "^0.95.1",
     "winston": "^3.2.1",
     "yn": "^4.0.0"
   },
@@ -51,6 +52,7 @@
   },
   "files": [
     "dist",
+    "migrations/**/*.{js,d.ts}",
     "static"
   ]
 }