HTML to PDF with AWS Lambda, Wkhtmltopdf, Terraform

HTML to PDF converter hosted in AWS Lambda, using:

• Terraform to provision the Lambda
• Typescript to invoke the Wkhtmltopdf

Blog post describing the problem & solution: https://karask.com/generate-html-to-pdf-using-aws-lambda-and-wkhtmltopdf

Deploy

Modify the Lambda name and S3 bucket inside the variables.tf

npm run build
terraform apply

How to use

After deploying you can invoke the Lambda using the published function URL:

curl -H 'Content-Type: application/json' \
  -d '{"uri": "https://www.google.com", "fileName": "sample.pdf"}' \
  -X POST $(terraform output -raw function_url) -i

Where uri is either an URL or S3 file key.

Available parameters are:

{
  "uri": "https://example.com", // URL or input S3 key
  "fileName": "converted.pdf" // Name of the converted file,
  "orientation": "Landscape", // Optional: Landscape or Portrait
  "marginTop:": "number", // Optional: top margin
  "marginRight": "number", // Optional: right margin
  "marginBottom": "number", // Optional: bottom margin
  "marginLeft": "number" // Optional: left margin
}

This then triggers the Lambda, passes the options to Wkhtmltopdf and saves the converted PDF to a configured S3 bucket.

HTTP/1.1 200 OK
Date: Sat, 11 Mar 2023 04:51:55 GMT
Content-Type: application/json

{"message":"File saved to lambda-html-to-pdf-files/sample.pdf"}

or you might get a validation error if you missed something:

HTTP/1.1 400 Bad Request
Date: Sat, 11 Mar 2023 04:53:33 GMT
Content-Type: application/json

{"message":"fileName not set"}

Utilities

Tailing the Lambda logs

aws logs tail "$(terraform output -raw lambda_log_group)" --follow

Copy and open the downloaded file (Mac), replace open with start on Windows

aws s3 cp "s3://$(terraform output -raw s3_bucket)/sample.pdf" . && open sample.pdf