fix: simplify scanner module by removing the usage of class

The class was initially added to conceptually separate the scanning/processing logic from the rest of the code. This separation is in order to later transfer this piece of logic into a separate worker mechanism, e.g. a Kubernetes Job. This separation however never happened, and this is the only place in the code that uses a class but without an apparent reason.

Convert the class functions into plain async functions and export them in the scanner module.

Author: ivanstanev

src/scanner/index.ts

@@ -5,64 +5,58 @@ import { constructDeleteWorkload, constructDepGraph } from '../transmitter/paylo
 import { IWorkload, ILocalWorkloadLocator } from '../transmitter/types';
 import { IPullableImage } from './images/types';
 
-export = class WorkloadWorker {
-  private readonly name: string;
-
-  constructor(name: string) {
-    this.name = name;
+export async function processWorkload(workloadMetadata: IWorkload[]): Promise<void> {
+  // every workload metadata references the same workload name, grab it from the first one
+  const workloadName = workloadMetadata[0].name;
+  const allImages = workloadMetadata.map((meta) => meta.imageName);
+  logger.info({workloadName, imageCount: allImages.length}, 'queried workloads');
+  const uniqueImages = [...new Set<string>(allImages)];
+
+  logger.info({workloadName, imageCount: uniqueImages.length}, 'pulling unique images');
+  const imagesWithFileSystemPath = getImagesWithFileSystemPath(uniqueImages);
+  const pulledImages = await pullImages(imagesWithFileSystemPath);
+  if (pulledImages.length === 0) {
+    logger.info({workloadName}, 'no images were pulled, halting scanner process.');
+    return;
   }
 
-  public async process(workloadMetadata: IWorkload[]): Promise<void> {
-    const workloadName = this.name;
-    const allImages = workloadMetadata.map((meta) => meta.imageName);
-    logger.info({workloadName, imageCount: allImages.length}, 'queried workloads');
-    const uniqueImages = [...new Set<string>(allImages)];
-
-    logger.info({workloadName, imageCount: uniqueImages.length}, 'pulling unique images');
-    const imagesWithFileSystemPath = getImagesWithFileSystemPath(uniqueImages);
-    const pulledImages = await pullImages(imagesWithFileSystemPath);
-    if (pulledImages.length === 0) {
-      logger.info({workloadName}, 'no images were pulled, halting scanner process.');
-      return;
-    }
-
-    try {
-      await this.scanImagesAndSendResults(workloadName, pulledImages, workloadMetadata);
-    } finally {
-      await removePulledImages(pulledImages);
-    }
+  try {
+    await scanImagesAndSendResults(workloadName, pulledImages, workloadMetadata);
+  } finally {
+    await removePulledImages(pulledImages);
   }
-
-  // TODO: should be extracted from here and moved to the supervisor
-  public async delete(localWorkloadLocator: ILocalWorkloadLocator): Promise<void> {
-    const deletePayload = constructDeleteWorkload(localWorkloadLocator);
-    logger.info({workloadName: this.name, workload: localWorkloadLocator},
-      'removing workloads from upstream');
-    await deleteWorkload(deletePayload);
+}
+
+// TODO: should be extracted from here and moved to the supervisor
+export async function sendDeleteWorkloadRequest(workloadName: string, localWorkloadLocator: ILocalWorkloadLocator): Promise<void> {
+  const deletePayload = constructDeleteWorkload(localWorkloadLocator);
+  logger.info({workloadName, workload: localWorkloadLocator},
+    'removing workloads from upstream');
+  await deleteWorkload(deletePayload);
+}
+
+async function scanImagesAndSendResults(
+  workloadName: string,
+  pulledImages: IPullableImage[],
+  workloadMetadata: IWorkload[],
+): Promise<void> {
+  const scannedImages = await scanImages(pulledImages);
+
+  if (scannedImages.length === 0) {
+    logger.info({workloadName}, 'no images were scanned, halting scanner process.');
+    return;
   }
 
-  private async scanImagesAndSendResults(
-    workloadName: string,
-    pulledImages: IPullableImage[],
-    workloadMetadata: IWorkload[],
-  ): Promise<void> {
-    const scannedImages = await scanImages(pulledImages);
-
-    if (scannedImages.length === 0) {
-      logger.info({workloadName}, 'no images were scanned, halting scanner process.');
-      return;
-    }
+  logger.info({workloadName, imageCount: scannedImages.length}, 'successfully scanned images');
 
-    logger.info({workloadName, imageCount: scannedImages.length}, 'successfully scanned images');
+  const depGraphPayloads = constructDepGraph(scannedImages, workloadMetadata);
+  await sendDepGraph(...depGraphPayloads);
 
-    const depGraphPayloads = constructDepGraph(scannedImages, workloadMetadata);
-    await sendDepGraph(...depGraphPayloads);
+  const pulledImagesNames = pulledImages.map((image) => image.imageName);
+  const pulledImageMetadata = workloadMetadata.filter((meta) =>
+    pulledImagesNames.includes(meta.imageName),
+  );
 
-    const pulledImagesNames = pulledImages.map((image) => image.imageName);
-    const pulledImageMetadata = workloadMetadata.filter((meta) =>
-      pulledImagesNames.includes(meta.imageName),
-    );
+  logger.info({workloadName, imageCount: pulledImageMetadata.length}, 'processed images');
+}
 
-    logger.info({workloadName, imageCount: pulledImageMetadata.length}, 'processed images');
-  }
-};

src/supervisor/watchers/handlers/pod.ts

@@ -2,7 +2,7 @@ import { V1Pod } from '@kubernetes/client-node';
 import async = require('async');
 import config = require('../../../common/config');
 import logger = require('../../../common/logger');
-import WorkloadWorker = require('../../../scanner');
+import { processWorkload } from '../../../scanner';
 import { sendWorkloadMetadata } from '../../../transmitter';
 import { IWorkload } from '../../../transmitter/types';
 import { constructWorkloadMetadata } from '../../../transmitter/payload';
@@ -28,9 +28,9 @@ function deleteFailedKeysFromState(keys): void {
 }
 
 async function queueWorkerWorkloadScan(task, callback): Promise<void> {
-  const {workloadWorker, workloadMetadata, imageKeys} = task;
+  const {workloadMetadata, imageKeys} = task;
   try {
-    await workloadWorker.process(workloadMetadata);
+    await processWorkload(workloadMetadata);
   } catch (err) {
     logger.error({err, task}, 'error processing a workload in the pod handler 2');
     deleteFailedKeysFromState(imageKeys);
@@ -54,7 +54,7 @@ metadataToSendQueue.error(function(err, task) {
   logger.error({err, task}, 'error processing a workload metadata send task');
 });
 
-function handleReadyPod(workloadWorker: WorkloadWorker, workloadMetadata: IWorkload[]): void {
+function handleReadyPod(workloadMetadata: IWorkload[]): void {
   const imagesToScan: IWorkload[] = [];
   const imageKeys: string[] = [];
   for (const image of workloadMetadata) {
@@ -68,7 +68,7 @@ function handleReadyPod(workloadWorker: WorkloadWorker, workloadMetadata: IWorkl
   }
 
   if (imagesToScan.length > 0) {
-    workloadsToScanQueue.push({workloadWorker, workloadMetadata: imagesToScan, imageKeys});
+    workloadsToScanQueue.push({workloadMetadata: imagesToScan, imageKeys});
   }
 }
 
@@ -106,9 +106,7 @@ export async function podWatchHandler(pod: V1Pod): Promise<void> {
       metadataToSendQueue.push({workloadMetadataPayload});
     }
 
-    const workloadName = workloadMember.name;
-    const workloadWorker = new WorkloadWorker(workloadName);
-    handleReadyPod(workloadWorker, workloadMetadata);
+    handleReadyPod(workloadMetadata);
   } catch (error) {
     logger.error({error, podName}, 'could not build image metadata for pod');
   }

src/supervisor/watchers/handlers/workload.ts

@@ -1,6 +1,6 @@
 import { IKubeObjectMetadata } from '../../types';
 import { buildWorkloadMetadata } from '../../metadata-extractor';
-import WorkloadWorker = require('../../../scanner');
+import { sendDeleteWorkloadRequest } from '../../../scanner';
 import logger = require('../../../common/logger');
 
 export async function deleteWorkload(kubernetesMetadata: IKubeObjectMetadata, workloadName: string): Promise<void> {
@@ -10,8 +10,7 @@ export async function deleteWorkload(kubernetesMetadata: IKubeObjectMetadata, wo
     }
 
     const localWorkloadLocator = buildWorkloadMetadata(kubernetesMetadata);
-    const workloadWorker = new WorkloadWorker(workloadName);
-    await workloadWorker.delete(localWorkloadLocator);
+    await sendDeleteWorkloadRequest(workloadName, localWorkloadLocator);
   } catch (error) {
     logger.error({error, resourceType: kubernetesMetadata.kind, resourceName: kubernetesMetadata.objectMeta.name},
       'could not delete workload');