feat(loopback4-example-shopping): add migration script

Add migration.ts and package scripts

Signed-off-by: dougal83 <[email protected]>

package.json

@@ -18,6 +18,7 @@
     "commitmsg": "commitlint -E GIT_PARAMS",
     "docker:start": "./bin/start-dbs.sh",
     "docker:stop": "./bin/stop-dbs.sh",
+    "migrate": "node ./packages/shopping/dist/migrate",
     "lint": "npm run prettier:check && npm run eslint",
     "lint:fix": "npm run prettier:fix && npm run eslint:fix",
     "prettier:cli": "lb-prettier \"**/*.ts\" \"**/*.js\" \"**/*.md\"",

packages/shopping/package.json

@@ -17,6 +17,7 @@
     "clean": "lb-clean dist*",
     "docker:start": "../../bin/start-dbs.sh",
     "docker:stop": "../../bin/stop-dbs.sh",
+    "migrate": "node ./dist/migrate",
     "pretest": "npm run clean && npm run build && npm run docker:start",
     "pretest:ci": "npm run build",
     "test": "lb-mocha --allow-console-logs \"dist/__tests__/**/*.js\"",

packages/shopping/src/migrate.ts

@@ -0,0 +1,20 @@
+import {ShoppingApplication} from './application';
+
+export async function migrate(args: string[]) {
+  const existingSchema = args.includes('--rebuild') ? 'drop' : 'alter';
+  console.log('Migrating schemas (%s existing schema)', existingSchema);
+
+  const app = new ShoppingApplication();
+  await app.boot();
+  await app.migrateSchema({existingSchema});
+
+  // Connectors usually keep a pool of opened connections,
+  // this keeps the process running even after all work is done.
+  // We need to exit explicitly.
+  process.exit(0);
+}
+
+migrate(process.argv).catch(err => {
+  console.error('Cannot migrate database schema', err);
+  process.exit(1);
+});