HtmlToPdfPythonLambda

Inspired from https://github.com/21Buttons/pychromeless

How to

On Dev

Installation

You must have docker and Docker compose installed. Virtualenv your project if you want to (virtualenv . -p /usr/local/bin/python3, source bin/activate) run make fetch-dependencies.

Run

make fetch-dependencies make docker-run

On Production

Creating the zip deployment package

run make build-lambda-package

Creating a AWS lambda instance

Following those steps:

• go to the create function insterface, and select the author form scratch option.
• set a name and the runtime to Python 3
• create a new role with admin access, and just select the default options that are proposed to you
• You are then re-directed to editor interface of your function
  • in the function code part:
    • under the "Code entry type"
    • select "Upload .zip file"
    • upload the zip that you've created with the makefile function. (if it's too big, upload it to s3)
    • in the handler set the path to your function like: module.file_name.method_name
  • in the environnement variable
    • PYTHONPATH=/var/task/src:/var/task/lib
    • PATH=/var/task/bin
  • in the basic setting section
    • Timeout: +10 seconds
    • Memory: + 250MB
  • in the editor part
    • Add a API Gateaway. In the configure triggers section that just appears:
      • select the "create new API" option
      • select whatever security option you want
  • click save and wait for the Lambda and API Gateaway to be created.
    • (Optional) Go to the API Gateaway editor and you can there create a new method endpoint
      • select the GET type
      • select the "Lambda Function" integration type
      • Tick the "Use Lambda Proxy integration" checkbox
      • select your lambda function that you've just created

Use

Now that you have an open API gateaway, you just have to use it's url and do a GET method on it with a GET param named url.

Explanation

Running a python lambda function on AWS Lambda

To create a Lambda function, you first package your code and dependencies in a deployment package. Then, you upload the deployment package to AWS Lambda to create your Lambda function. https://docs.aws.amazon.com/lambda/latest/dg/lambda-app.html

So basically, AWS can run any python code with any dependancies if you install them in a directory and zip it. For automation, this step is done in a Makefile, the build-lambda-package.

Generation of PDF

It's base on the pdfkit package, which rely on wkhtmltopdf.

TODO

• make it work with pdfkit
• reduce package size
• make docker test works with the event part

Testing with docker-lambda

https://github.com/lambci/docker-lambda

Just run make docker-run