refactor(server): update setup function to to validation immediately after loading the storage layer

Author: pharindoko

src/server/app/core.app.ts

@@ -6,10 +6,12 @@ import jsonServer = require('json-server');
 import { StorageAdapter } from '../storage/storage';
 import { ApiSpecification } from '../specifications/apispecification';
 import { JSONValidator } from '../validations/json.validator';
+import { Output } from '../utils/output';
 
 export class CoreApp {
   storageAdapter: StorageAdapter;
   static storage = {} as lowdb.AdapterAsync;
+  static adapter = {} as lowdb.LowdbAsync<{}>;
   logger = new Logger().logger;
   appConfig: AppConfig;
   protected server: express.Express;
@@ -29,27 +31,39 @@ export class CoreApp {
 
   async setup(): Promise<void> {
     await this.setupStorage();
-    const json = await this.setupApp();
-    this.validateJSON(json);
+    const json = await this.getJSON();
+    const isValid = this.validateJSON(json);
+    if (isValid) {
+    await this.setupApp();
     this.setupSwagger(json);
     await this.setupRoutes();
+    } else {
+      Output.setError("provided json is not valid - see validation checks")
+      throw Error("provided json is not valid - see validation checks");
+    }
   }
 
   protected async setupStorage() {
     CoreApp.storage = await this.storageAdapter.init();
+    CoreApp.adapter = await lowdb.default(CoreApp.storage);
   }
 
-  protected async setupApp(): Promise<object> {
-    const { middlewares, router, adapter } = await this.initializeLayers();
+  protected async setupApp(): Promise<void> {
+    const { middlewares, router } = await this.initializeLayers();
     this.setupServer(middlewares, router);
-    const json = await adapter.getState();
-    return json;
   }
 
-  protected validateJSON(db: {}): void {
-    if (this.appConfig.enableSwagger) {
-      const validator = JSONValidator.validate(db);
+  protected validateJSON(db: {}): boolean {
+    let isValid = true;
+    if (this.appConfig.enableJSONValidation) {
+      isValid = JSONValidator.validate(db);
     }
+    return isValid;
+  }
+
+  protected async getJSON(): Promise<object> {
+    const json = await CoreApp.adapter.getState();
+    return json;
   }
 
   protected setupSwagger(db: {}): void {
@@ -65,12 +79,14 @@ export class CoreApp {
   }
 
   protected async initializeLayers() {
-    const adapter = await lowdb.default(CoreApp.storage);
-    const router = jsonServer.router(adapter);
+    if (CoreApp.adapter && Object.entries(CoreApp.adapter).length === 0 && CoreApp.adapter.constructor === Object) {
+      CoreApp.adapter = await lowdb.default(CoreApp.storage);
+    }
+    const router = jsonServer.router(CoreApp.adapter);
     const middlewares = jsonServer.defaults({
       readOnly: this.appConfig.readOnly,
     });
-    return { middlewares, router, adapter };
+    return { middlewares, router};
   }
 
   protected setupServer(