fix: nlu cleanup of old models

modules/nlu/src/backend/pipelines/intents/ft_classifier.ts

@@ -33,6 +33,12 @@ export default class FastTextClassifier implements IntentClassifier {
     return Promise.fromCallback(cb => fileStream.end(cb))
   }
 
+  private teardownModels() {
+    if (this._modelsByContext) {
+      _.values(this._modelsByContext).forEach(x => x.cleanup())
+    }
+  }
+
   private _hasSufficientData(intents: sdk.NLU.IntentDefinition[]) {
     const datasetSize = _.flatMap(intents, intent => intent.utterances).length
     return intents.length > 0 && datasetSize > 0
@@ -86,6 +92,7 @@ export default class FastTextClassifier implements IntentClassifier {
       }
     }
 
+    this.teardownModels()
     this._modelsByContext = modelsByContext
 
     return models
@@ -111,6 +118,7 @@ export default class FastTextClassifier implements IntentClassifier {
       m[model.name] = ft
     }
 
+    this.teardownModels()
     this._modelsByContext = m
   }
 

src/bp/ml/fasttext.ts

@@ -1,4 +1,3 @@
-import { reject, resolve } from 'bluebird'
 import * as sdk from 'botpress/sdk'
 import { VError } from 'verror'
 
@@ -34,6 +33,11 @@ export class FastTextModel implements sdk.MLToolkit.FastText.Model {
 
   constructor(private lazy: boolean = true, private keepInMemory = false) {}
 
+  cleanup() {
+    this._modelPromise = undefined
+    this._queryPromise = undefined
+  }
+
   async trainToFile(
     method: sdk.MLToolkit.FastText.TrainCommand,
     modelPath: string,

src/bp/sdk/botpress.d.ts

@@ -190,6 +190,7 @@ declare module 'botpress/sdk' {
       }
 
       export interface Model {
+        cleanup: () => void
         trainToFile: (method: TrainCommand, modelPath: string, args: Partial<TrainArgs>) => Promise<void>
         loadFromFile: (modelPath: string) => Promise<void>
         predict: (str: string, nbLabels: number) => Promise<PredictResult[]>