feat: wait for monitor resource cleanup

Wait for the cancel error from the CLI when requesting connection close.

Signed-off-by: Akos Kitta <[email protected]>

Author: Akos Kitta

arduino-ide-extension/src/node/monitor-service.ts

@@ -410,6 +410,8 @@ export class MonitorService extends CoreClientAware implements Disposable {
     ]) as Promise<unknown> as Promise<void>;
   }
 
+  private closingDuplex: Promise<void> | undefined;
+
   /**
    * Pauses the currently running monitor, it still closes the gRPC connection
    * with the underlying monitor process but it doesn't stop the message handlers
@@ -419,28 +421,41 @@ export class MonitorService extends CoreClientAware implements Disposable {
    * @returns
    */
   async pause(): Promise<void> {
-    return new Promise(async (resolve) => {
-      if (!this.duplex) {
-        this.logger.warn(
-          `monitor to ${this.port?.address} using ${this.port?.protocol} already stopped`
-        );
-        return resolve();
-      }
-      await new Promise<void>((closeResolve) => {
-        if (!this.duplex) {
-          return closeResolve();
-        }
-        this.duplex.write(new MonitorRequest().setClose(true), closeResolve);
-      });
-      this.duplex.on('end', resolve);
+    const duplex = this.duplex;
+    if (!duplex) {
+      this.logger.warn(
+        `monitor to ${this.port?.address} using ${this.port?.protocol} already stopped`
+      );
+      return;
+    }
+    if (this.closingDuplex) {
+      return this.closingDuplex;
+    }
+    const deferredClose = new Deferred<void>();
+    this.closingDuplex = deferredClose.promise;
+
+    // to terminate the monitor connection, send a close request, and wait for the expected cancellation error
+    duplex.once('error', (error) => {
+      // TODO: check if cancel error
+      deferredClose.resolve();
     });
+    duplex.write(new MonitorRequest().setClose(true));
+    try {
+      await this.closingDuplex;
+    } finally {
+      this.closingDuplex = undefined;
+    }
+    // Sanity check
+    if (!duplex.closed) {
+      throw new Error('Could not close monitor connection');
+    }
   }
 
   /**
    * Stop the monitor currently running
    */
   async stop(): Promise<void> {
-    return this.pause().finally(this.stopMessagesHandlers.bind(this));
+    return this.pause().finally(() => this.stopMessagesHandlers());
   }
 
   /**