Image Processing

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Introduction

This example demonstrates how to process images using Upstash Workflow. The following workflow will upload an image, resize it into multiple resolutions, apply filters, and store the processed versions for later retrieval.

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Use Case

Our workflow will:

1. Receive an image upload request
2. Resize the image into different resolutions
3. Apply various filters to the resized images
4. Store the processed images in a cloud storage

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Code Example

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Code Breakdown

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1. Retrieving the Image

We begin by getting the URL of the uploaded image based on its ID:

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2. Resizing the Image

We resize the image into three different resolutions (640, 1280, 1920) using an external image processing service.

We call context.call for each resolution and use Promise.all to run them parallel:

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3. Applying Filters

After resizing, we apply filters such as grayscale, sepia, and contrast to the resized images.

Again, we call context.call for each filter & image pair. We collect the promises of these requests in an array processedImagePromise. Then, we call Promise.all again to run them all parallel.

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4. Storing the Processed Images

We store each processed image in cloud storage and return the URLs of the stored images:

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Key Features

1. Batch Processing: This workflow handles batch resizing and filtering of images in parallel to minimize processing time.
2. Scalability: Image resizing and filtering are handled through external services, making it easy to scale. Also, the requests to these services are handled by QStash, not by the compute where the workflow is hosted.
3. Storage Integration: The workflow integrates with cloud storage to persist processed images for future access.