This works 100% on pantheon, using the library this way:
https://pantheon.io/docs/external-libraries/

CONTENTS OF THIS FILE
---------------------

* Introduction
* Installation
* Configuration
* Pdf Generation
* Maintainers

INTRODUCTION
------------

Provide a path to convert any url to pdf, using wkhtmltopdf library https://wkhtmltopdf.org.
This module was develop to run on Pantheon, but can be used in any server. If you are using pantheon, follow the instruction here
https://pantheon.io/docs/external-libraries/ to use wkhtmltopdf

INSTALLATION
------------

* Install as usual, see
https://www.drupal.org/docs/8/extending-drupal-8/installing-contributed-... for further
information.

CONFIGURATION
-------------

* In this current version, its necessary to have wkhtmltopdf installed. Set the binary on /admin/config/wkhtmltopdf (Configuration -> Settings -> Wkhtmltopdf settings).
* If you are using Patheon and have configured https://pantheon.io/docs/external-libraries/ already, just add the link sites/all/libraries/wkhtmltopdf/wkhtmltopdf on Wkhtmltopdf settings.

PDF GENERATION
--------------

* PDF Generation (at /wkhtmltopdf/generatepdf?url=[absolute-path-to-generate]). Full link example for /node/123: (www.example.com/wkhtmltopdf/generatepdf?url=[absolute-path-to-generate])
* Example for node/123 (at www.example.com/wkhtmltopdf/generatepdf?url=www.example.com/node/123)

MAINTAINERS
-----------

Current maintainers:

* Julio Hidemi Kamizato (https://www.drupal.org/u/jkamizato)

Supporting organizations: 

Project information

Releases