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Playwright on Alpine Linux

NOTE: This feature is EXPERIMENTAL.

Playwright actually requires a permission for shell command execution, and many run-time dependencies for each browser.

all-in-one

This all-in-one architecture is reasonable for browser automation in our own computers.

However we may have trouble with bringing Playwright into:

  • Docker
    • Alpine Linux
  • Serverless computing
    • AWS Lambda
    • Google Cloud Functions
  • PaaS
    • Heroku
    • Google App Engine

This article introduces a way to separate environments into client (for executing Playwright script) and server (for working with browsers). The main use-case assumes Docker (using Alpine Linux), however the way can be applied also into other use-cases.

ref: https://playwright.dev/docs/docker#remote-connection

Overview​

Playwright Ruby client is running on Alpine Linux. It just sends/receives JSON messages of Playwright-protocol via WebSocket.

Playwright server is running on a container of official Docker image. It just operates browsers in response to the JSON messages from WebSocket.

overview

  • Server can be launched with npx playwright run-server CLI command.
  • Client can connect to server with BrowserType#connect. In playwright-ruby-client, BrowserType#connect and not implemented yet and use Playwright#connect_to_browser_server() instead.

Client code​

Many example uses Playwright#create, which internally uses Pipe (stdin/stdout) transport for Playwright-protocol messaging. Instead, use Playwright#connect_to_browser_server(endpoint) for WebSocket transport.

require 'playwright'

Playwright.connect_to_browser_server('wss://example.com:8888/ws') do |browser|
  page = browser.new_page
  page.goto('https://github.com/microsoft/playwright')
  page.screenshot(path: 'github-microsoft-playwright.png')
end

wss://example.com:8888/ws is an example of endpoint URL of the Playwright server. In local development environment, it is typically "ws://127.0.0.1:#{port}/ws".

Server code​

With the official Docker image or in the local development environment with Node.js, just execute npx playwright install && npx playwright run-server --port $PORT --path /ws. ($PORT is a port number of the server)

If custom Docker image is preferred, build it as follows:

FROM mcr.microsoft.com/playwright

WORKDIR /root
RUN npm install playwright && ./node_modules/.bin/playwright install

ENV PORT 8888
CMD ["./node_modules/.bin/playwright", "run-server", "--port", "$PORT", "--path", "/ws"]

Debugging for connection​

The client and server are really quiet. This chapter shows how to check if the communication on the WebSocket works well or not.

Show JSON message on client​

Just set an environment variable DEBUG=1.

DEBUG=1 bundle exec ruby some-automation-with-playwright.rb

Enable verbose logging on server​

Just set an environment variable DEBUG=pw:* or DEBUG=pw:server

DEBUG=pw:* npx playwright run-server --browser chromium

See the official documentation for details.