PhantomJS in AWS Lambda (Missing libfontconfig)

Question

I am trying to get my lambda function to use phantomjs, however it keeps running into an error of a missing dependency: libfontconfig / fontconfig. On my Centos VPS when I install fontconfig (dnf install fontconfig -y) my code works fine. However when running on lambda I cannot figure out how to get this library to be ran with my function.

This is my code: (Attempting to get the best selling products through the AliExpress package, which uses phantomjs)

const aliExpress = require('aliexpress');

exports.handler = (event, context, callback) => {
    console.log('Handler ran!');
    aliExpress.BestSelling.get().then((goods) => {
        console.log('Found results!');
        const urls = [];
        for(let index in goods) {
            const url = goods[index].url;
            urls.push(url);
        }
        console.log('Returning URLs:');
        console.log(urls);
        callback(null, urls);
    }).catch((err) => {
        console.log('Error:');
        console.log(err);
        callback(err);
    });
};

// For testing on VPS
exports.handler(null, null, (err, result) => {
    if(err) {
        console.log('Err:');
        console.log(err);
    } else {
        console.log('Result:');
        console.log(result);
    }
});

I am expecting the result to be an array of AliExpress URLs, this is what happens whenever I run it with fontconfig installed on my VPS. However, on my lambda function AND on my VPS without fontconfig installed I am getting this error:

Handler ran!
(node:1966) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Error reading from stdin: Error: write EPIPE
(node:1966) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
error: /home/function/node_modules/phantomjs-prebuilt/lib/phantom/bin/phantomjs: error while loading shared libraries: libfontconfig.so.1: cannot open shared object file: No such file or directory

I believe I now either have to 1) Figure out how to run phantomjs without this dependency or 2) Figure out how to install this dependency to my Lambda function's "server"

Perhaps there's a previous version of phantomjs that gives me the functionality I want without this dependency? Not sure

Anyone know how I can solve this problem? Thank you!

Answer 1

Here's what I just got to work for custom fonts on AWS Lambda with pandoc/xelatex. I'd bet you can adapt it to do something similar for your use case.

I created a fonts directory in my project and placed all of my fonts there. Also in that directory I created a fonts.conf file that looks like this:

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <dir>/var/task/fonts/</dir>
  <cachedir>/tmp/fonts-cache/</cachedir>
  <config></config>
</fontconfig>

And then in my (node.js based) handler function before shelling out to call pandoc I set an ENV var to tell fontconfig where to find the fonts.

process.env.FONTCONFIG_PATH='/var/task/fonts'

After doing that I can refer to a font, like Bitter, in my template by name (just Bitter) and then pandoc/xelatex/fontconfig/whatever knows which version of the font to use (like Bitter-Bold.otf vs Bitter-Italic.otf) based on the styling that any bit of text is supposed to have.

I figured this out based on the tips in this project for getting RSVG to work with custom fonts on Lambda: https://github.com/claudiajs/rsvg-convert-aws-lambda-binary/blob/master/README.md#using-custom-fonts

Answer 2

For those ending up there, here's my little story: I wanted to use a Roboto font to generate html-template-based PDF with phantomJs on a AWS Lambda execution.

My application 'App' is in nodeJs and depends on a 'RunTimeDep' dependency which executes a bunch of useful stuff for App at runtime. Among those tasks, it generates a PDF based on a html template, in which I wanted to use Roboto Mono. Just to mention, the html template is in 'App'.

To do so, I created the /fonts folder as @Jeremy Green mentionned in the 'RunTimeDep' module. I converted the Roboto fonts into PFB format, and put them there. I added thus this fonts.conf:

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <dir>/var/task/node_modules/RunTimeDep/fonts/</dir>
  <cachedir>/tmp/fonts-cache/</cachedir>
  <config></config>
</fontconfig>

Finally, I added the FONTCONFIG_PATH to point to /var/task/node_modules/RunTimeDep/fonts/ (I used serverless envrionment variable, but process.env should be fine too)

And this actually worked just great