Installation: AWS Lambda

Canvas 2.0 and 1.6 works out-of-the-box on AWS Lambda thanks to prebuilds. However, you must build your Lambda ZIP file on Linux (or a Linux Docker container) so that the correct prebuilt binary is included. See https://github.com/Automattic/node-canvas/issues/1231 for more info.

The below instructions can be used for older versions or custom builds.

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Lambda doesn't have the required libraries installed by default, but it can load them from either the ./ or ./lib directories in your packaged function.

Create an EC2 VM from the the Lambda AMI, we'll use this to build canvas and grab compatible libraries.

Install Node and development tools:

sudo yum groupinstall "Development Tools" -y
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.8/install.sh | bash

# Exit SSH session and reopen here to make nvm available

# Node 6.10:
nvm install 6.10
# Or Node 8.10:
nvm install 8.10

Install node-canvas as you normally would on Linux:

sudo yum install cairo-devel libjpeg-turbo-devel giflib-devel pango-devel -y
npm install canvas@next

Then copy the system libraries from /usr/lib64/ into a ./lib/ subdirectory for your Lambda function:

mkdir lib
cp /usr/lib64/{libpng12.so.0,libjpeg.so.62,libpixman-1.so.0,libfreetype.so.6,\
libcairo.so.2,libpango-1.0.so.0,libpangocairo-1.0.so.0,libpangoft2-1.0.so.0} lib/

At this point you can package up the node_modules and lib directories and download them to your local machine. The node_modules/canvas/build/Release/canvas.node library has been built for the Lambda architecture, so don't overwrite it by rebuilding the canvas package on your local machine.

Then you can add an index.js handler to test Canvas with:

let
	{createCanvas} = require("canvas");

function hello(event, context, callback) {
	let
		canvas = createCanvas(200, 200),
		ctx = canvas.getContext('2d');

	// Write "Awesome!"
	ctx.font = '30px Impact';
	ctx.rotate(0.1);
	ctx.fillText('Awesome!', 50, 100);

	// Draw line under text
	let
		text = ctx.measureText('Awesome!');
	ctx.strokeStyle = 'rgba(0,0,0,0.5)';
	ctx.beginPath();
	ctx.lineTo(50, 102);
	ctx.lineTo(50 + text.width, 102);
	ctx.stroke();

	callback(null, '<img src="' + canvas.toDataURL() + '" />');
}

module.exports = {hello};

You can now zip up this function and manually deploy it to Lambda (just set Node to 6.10 and the handler to index.hello), or you can deploy it using Serverless. For Serverless, add a serverless.yml file to the root of your project:

service: canvas-test

provider:
  name: aws
  runtime: nodejs6.10
  stage: dev
  region: us-east-1
  memorySize: 128
  timeout: 10

functions:
  hello:
    handler: index.hello

The resulting project structure:

├── index.js
├── lib
│   ├── libcairo.so.2
│   ├── libfreetype.so.6
│   ├── libjpeg.so.62
│   ├── libpango-1.0.so.0
│   ├── libpangocairo-1.0.so.0
│   ├── libpangoft2-1.0.so.0
│   ├── libpixman-1.so.0
│   └── libpng12.so.0
├── node_modules
│   ├── canvas
│           ....
│   └── nan
│           ....
└── serverless.yml

Call serverless deploy to deploy it to Lambda, and serverless invoke --function hello to run it, and you should get back the HTML for this successful result:

Using newer versions of libcairo

The version of Amazon Linux that Lambda uses includes libcairo v1.12, which produces noticeably poor results when downscaling images with drawImage(). This was fixed in Cairo v1.14. You can use the install instructions for EC2 (Installation - Amazon-Linux-AMI-(EC2)) to build libcairo 1.14 and libpixman 0.34 from source, and replace the libcairo.so.2 and libpixman-1.so.0 binaries in your Lambda's lib directory with the resulting libraries (you can find those built libraries in /usr/local/lib).

However, due to the ordering of the directories in Lambda's LD_LIBRARY_PATH (/var/lang/lib:/lib64:/usr/lib64:/var/runtime:/var/runtime/lib:/var/task:/var/task/lib) the operating system's included libcairo and libpixman will be used instead of the copies in your Lambda's lib directory. To fix this you need to set LDFLAGS during canvas installation:

export LDFLAGS=-Wl,-rpath=/var/task/lib
npm install canvas@next

This will set the RPATH flags in the built canvas.node library to look for libraries in /var/task/lib first (your Lambda's bundled lib directory). Update the copy of canvas.node in your Lambda's lib directory with this newly-built version.