Fix EMFILE error in local training service (#1189)

src/nni_manager/training_service/local/localTrainingService.ts

@@ -355,7 +355,8 @@ class LocalTrainingService implements TrainingService {
         this.log.info('Stopping local machine training service...');
         this.stopping = true;
         for (const stream of this.jobStreamMap.values()) {
-            stream.destroy();
+            stream.end(0)
+            stream.emit('end')
         }
         if (this.gpuScheduler !== undefined) {
             await this.gpuScheduler.stop();
@@ -372,7 +373,9 @@ class LocalTrainingService implements TrainingService {
                 if (stream === undefined) {
                     throw new Error(`Could not find stream in trial ${trialJob.id}`);
                 }
-                stream.destroy();
+                //Refer https://github.com/Juul/tail-stream/issues/20
+                stream.end(0)
+                stream.emit('end')
                 this.jobStreamMap.delete(trialJob.id);
             }
         }
@@ -567,7 +570,6 @@ class LocalTrainingService implements TrainingService {
                 buffer = remain;
             }
         });
-
         this.jobStreamMap.set(trialJobDetail.id, stream);
     }
 

src/nni_manager/types/tail-stream/index.d.ts

 declare module 'tail-stream' {
     export interface Stream {
         on(type: 'data', callback: (data: Buffer) => void): void;
-        destroy(): void;
+        end(data: number): void;
+        emit(data: string): void;
     }
     export function createReadStream(path: string): Stream;
 }
\ No newline at end of file