add: shutdown lock method (#50)

Author: vpbs2

meerkat-dbm/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@devrev/meerkat-dbm",
-  "version": "0.0.141",
+  "version": "0.0.142",
   "dependencies": {
     "tslib": "^2.3.0",
     "@duckdb/duckdb-wasm": "^1.28.0",

meerkat-dbm/src/dbm/dbm.spec.ts

@@ -160,7 +160,7 @@ describe('DBM', () => {
   let db: AsyncDuckDB;
   let fileManager: FileManagerType;
   let dbm: DBM;
-  let instanceManager;
+  let instanceManager: InstanceManager;
 
   beforeAll(async () => {
     // eslint-disable-next-line @typescript-eslint/ban-ts-comment
@@ -179,6 +179,9 @@ describe('DBM', () => {
       onEvent: (event) => {
         console.log(event);
       },
+      options: {
+        shutdownInactiveTime: 100,
+      },
     };
     dbm = new DBM(options);
   });
@@ -389,5 +392,29 @@ describe('DBM', () => {
        */
       expect(instanceManager.terminateDB).not.toBeCalled();
     });
+
+    it('should not shutdown the db if the shutdown lock is true', async () => {
+      jest.spyOn(instanceManager, 'terminateDB');
+
+      /**
+       * Set the shutdown lock to true
+       */
+      dbm.setShutdownLock(true);
+
+      /**
+       * Execute a query
+       */
+      await dbm.queryWithTableNames('SELECT * FROM table1', ['table1']);
+
+      /**
+       * wait for 200ms
+       */
+      await new Promise((resolve) => setTimeout(resolve, 200));
+
+      /**
+       * Expect instanceManager.terminateDB to not be called
+       */
+      expect(instanceManager.terminateDB).not.toBeCalled();
+    });
   });
 });

meerkat-dbm/src/dbm/dbm.ts

@@ -17,6 +17,7 @@ export class DBM {
   private options: DBMConstructorOptions['options'];
   private terminateDBTimeout: NodeJS.Timeout | null = null;
   private onDuckDBShutdown?: () => void;
+  private shutdownLock = false;
 
   constructor({
     fileManager,
@@ -35,6 +36,13 @@ export class DBM {
   }
 
   private async _shutdown() {
+    /**
+     * If the shutdown lock is true, then don't shutdown the DB
+     */
+    if (this.shutdownLock) {
+      return;
+    }
+
     if (this.connection) {
       await this.connection.close();
       this.connection = null;
@@ -285,4 +293,11 @@ export class DBM {
      */
     return connection.query(query);
   }
+
+  /**
+   * Set the shutdown lock to prevent the DB from shutting down
+   */
+  public async setShutdownLock(state: boolean) {
+    this.shutdownLock = state;
+  }
 }