Apache OpenWhisk Image Resizing with WebAssembly

This repository contains a serverless function (for Apache OpenWhisk) to resize images using a C library called via WebAssembly. It is a fork of original code created by Cloudflare for their Workers platform. See the original repository for details on what the repository contains and how the files work.

Usage

• Create deployment package from source files.

zip action.zip resizer.wasm package.json worker.js

• Create Apache OpenWhisk action from deployment package.

ibmcloud wsk action update resizer action.zip --kind nodejs:10 --web true

• Retrieve HTTP URL for Web Action.

ibmcloud wsk action get resizer --url
ok: got action resizer
https://<region>.cloud.ibm.com/api/v1/web/<ns>/default/resizer <-- USE THIS URL

• Open the HTTP URL with the .http extension.

https://<region>.cloud.ibm.com/api/v1/web/<ns>/default/resizer.http

This should return the following image resized to 250 pixels (from 900 pixels).

URL query parameters (url and width) can be used to modify the image source or output width for the next image, e.g.

https://<region>.cloud.ibm.com/api/v1/web/<ns>/default/resizer.http?url=<IMG_URL>&width=500

How to re-build WASM file (OS X)

• Install LLVM.

brew install llvm
brew link --force llvm

• Remove existing WASM file (resize.wasm)

make clean

• Run build command (which uses clang).

make build