This is an AWS Lambda function that converts HTML pages created in S3 buckets to PDF documents using wkhtmltopdf (0.12.4).
This function is invoked through S3 notifications - we tend to use the 'object create event', although it should work for other events. Upon receiving the notification, it will pull down the referenced s3 object, convert it to a pdf, and stick a pdf file with the same key back into the bucket.
This function does not handle HTML generation itself, simply the conversion to HTML. For an example of using a pdf specific Blade template, checkout the CreateVaccinePdf Job in Adopterluv.
DANGER Note that this function goes against S3 + Lambda best practices (something we should consider rectifying at some point). Specifically, it is normally setup to listen to object created events and creates an object itself. If you are not careful, this could cause a massive infinite execution problem, and a rather unexpected AWS bill.
Hook up your S3 bucket by going to the lambda console, clicking on devZepHtmlToPdf or prodZepHtmlToPdf. On the config page, click 'Add trigger', which will walk you through the steps for adding an s3 trigger.
Your event configuration should look at lot like the notification-config-example file. Most importantly, ensure you have scoped your notifications to .html files to avoid infinite execution. You might also want to prefix the folder if docs are stored globally in a subfolder/key of a bucket.
There are two ways in which these functions can be deployed to AWS. The dev function can be used as a test function, if you do not want to setup the local testing. Simply connect your personal s3 bucket as a trigger on it.
Make sure your environment variables are set specifically FONTCONFIG_PATH=/var/task/fonts
1 (recommended) - Check our npm run deploy:dev and npm run deploy:prod commands in package.json and change it according to your needs. Do not forget to add environment variables (you can find it under template.yml) to your lambda function in aws lambda edit page or running lamba update-function-configuration command or ensure you edit the Lambda function directly.
or
2 (untested) - Check out template.yml file and edit according to your needs then use sam deploy.
The function can be tested locally using AWS SAM CLI. You can change contents of events/example-event.json or you can create a new file which you will give sam as an event parameter.
sam local invoke "devZepHtmlToPdf" -e events/example-event.json
- Some sort of build pipeline, currently needs to be deployed from a local computer
- Better logging... we have no way of knowing whether an actually useful pdf is output, just that some sort of pdf output.
- Pipe cloudwatch logs somewhere