Renderprime

A high performance and serverless prerenderer built as a GCP Cloud Function.

Features

• Asset caching through the default browser caching behavior.
• HTML document caching for instant app shell rendering. The document is revalidated every 10 minutes.
• Render parallelization up to the value of availableParallelism.

Getting Started

Installation

git clone https://github.com/theninthsky/renderprime.git
npm i

Running Locally

npm start

Environment Variables

WEBSITE_URL: The URL of the website without / at the end. Providing it will cause the HTML document to be cached, thus greatly reducing response times (default: undefined).

USER_AGENT: The navigator.userAgent string that will be injected to the browser during rendering (default: Prerender).

WAIT_AFTER_LAST_REQUEST: The number of milliseconds to wait after the last request before snapshotting the DOM. This has tight correlation to the CPU power (default: 200).

WAIT_AFTER_LAST_REQUEST_TIMEOUT: For how many milliseconds should the browser wait for the last request to return before giving up and snapshotting the DOM anyway (default: 5000).

Blocking Resources

Any request that does not render data on the screen should be blocked, this will allow the prerenderer to snapshot the page much faster.

Inside blocklists.js you will find two arrays: extensionBlocklist and urlBlocklist.
These will allow you to block resources by file extension and URL respectively.

Recommended Cloud Function Setup

Memory allocated: 1GB
CPU: 2
Maximum concurrent requests per instance: 4 (should match the availableParallelism of the CPU)