feat: task executor emits lifecycle events through an EventEmitter

JST-526

src/executor/events.ts

@@ -11,7 +11,7 @@ export interface TaskExecutorEventsDict {
    * Fires when task executor is about to shut down, immediately after TaskExecutor.shutdown() is called.
    *
    */
-  beforeend: () => void;
+  beforeEnd: () => void;
 
   /**
    * Fires when task executor is completely terminated.

src/executor/executor.spec.ts

@@ -157,12 +157,12 @@ describe("Task Executor", () => {
       expect(spy).toHaveBeenCalledTimes(1);
     });
 
-    it('it should emit "beforeend" and "end" events', async () => {
+    it('it should emit "beforeEnd" and "end" events', async () => {
       const executor = await TaskExecutor.create({ package: "test", startupTimeout: 0, logger, yagnaOptions });
       const beforeEnd = jest.fn();
       const end = jest.fn();
 
-      executor.events.on("beforeend", beforeEnd);
+      executor.events.on("beforeEnd", beforeEnd);
       executor.events.on("end", end);
 
       await executor.shutdown();

src/executor/executor.ts

@@ -284,6 +284,10 @@ export class TaskExecutor {
    * Stop all executor services and shut down executor instance.
    *
    * You can call this method multiple times, it will resolve only once the executor is shutdown.
+   *
+   * When shutdown() is initially called, a beforeEnd event is emitted.
+   *
+   * Once the executor is fully stopped, an end event is emitted.
    */
   shutdown(): Promise<void> {
     if (!this.isRunning) {
@@ -302,7 +306,7 @@ export class TaskExecutor {
    * @private
    */
   private async doShutdown() {
-    this.events.emit("beforeend");
+    this.events.emit("beforeEnd");
     if (runtimeContextChecker.isNode) this.removeSignalHandlers();
     clearTimeout(this.startupTimeoutId);
     if (!this.configOptions.storageProvider) await this.storageProvider?.close();