Add web workers configuration

backend/src/worker.ts

@@ -0,0 +1,134 @@
+import Bull, { Job } from 'bull';
+import ffmpeg from 'fluent-ffmpeg';
+
+// queue: Bull queue instance used for queuing thumbnail generation jobs.
+export const queue = new Bull('thumbnail-queue');
+
+export interface JobData {
+  videoId: string;
+  videoPath: string;
+  thumbnailPath: string;
+}
+
+export interface JobNotification {
+  type: string;
+  videoId: string;
+  message?: string;
+  error?: Error;
+}
+
+/**
+ * sendJobNotification:
+  - Sends a job notification and updates job progress
+  - @param notification: JobNotification object
+  - @param job: The job object
+  - Returns the notification error if type is 'job-failed', else returns true
+
+ */
+export function sendJobNotification(notification: JobNotification, job: Job) {
+  if (notification.type === 'job-failed') {
+    console.error(notification.error);
+    return notification.error;
+  }
+
+  job.progress(100);
+
+  console.log(
+    `Sending notification for ${notification.videoId}, message: ${notification.message}`,
+  );
+  return notification.message;
+}
+
+/**
+ *
+createJob:
+  - Adds a job to the queue and registers event handlers
+  - @param job: The job object
+  - Registers 'completed' and 'failed' event handlers that call sendJobNotification
+
+ */
+export async function createJob(jobData: JobData) {
+  const job = await queue.add(jobData);
+  return job.id;
+}
+
+/**
+ * processJob:
+  - Processes jobs from the queue
+  - @param job: The job object
+  - Uses ffmpeg to generate thumbnail and sends a 'thumbnail-generated' notification
+
+ */
+export function processJob(job: Job) {
+  return new Promise((resolve, reject) => {
+    let progress;
+    ffmpeg(job.data.videoPath)
+      .screenshots({
+        timestamps: ['50%'],
+        filename: job.data.thumbnailPath,
+      })
+      .on('start', () => {
+        progress = 0;
+        job.progress(progress);
+        sendJobNotification(
+          {
+            type: 'job-started',
+            videoId: job.data.videoId,
+            message: 'Thumbnail generation started',
+          },
+          job,
+        );
+      })
+      .on('progress', ({ percent }) => {
+        progress = percent;
+        job.progress(progress);
+      })
+      .on('end', () => {
+        job.progress(100);
+        sendJobNotification(
+          {
+            type: 'thumbnail-generated',
+            videoId: job.data.videoId,
+          },
+          job,
+        );
+        return resolve(true);
+      })
+      .on('error', (err) => {
+        sendJobNotification(
+          {
+            type: 'job-failed',
+            videoId: job.data.videoId,
+            error: err,
+          },
+          job,
+        );
+        return reject(err);
+      });
+  });
+}
+
+// queue.on('start', (job: Job) => {
+//   // Handle job start errors
+//   job.on('failed', (err: Error) => {
+//     console.error(`Job ${job.id} failed`, err);
+//   });
+// });
+
+queue.process(processJob);
+
+/**
+ * createPushNotificationjobs:
+  - Validates jobs array and creates jobs by calling createJob
+  - @param jobs: Array of job objects
+ */
+// export function createPushNotificationjobs(jobs: Job[]) {
+//   if (!Array.isArray(jobs) || jobs.length === 0) {
+//     throw Error('Invalid Jobs array');
+//   }
+//   jobs.forEach((job: Job) => {
+//     if (job) {
+//       createJob(job);
+//     }
+//   });
+// }