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playwright

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#cloud run #docker #playwright #python
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I recently ventured into deploying a service on Google Cloud Run. My goal was straightforward: create a service that fetches webpage titles and captures screenshots of URLs. However, the journey led me into a peculiar bug when I actually used it on Goole Cloud Run.

The Bug

During the development phase, I worked with a python:3.11-slim base image on macOS, and my Dockerfile functioned without a hitch. Here’s a snapshot of the Dockerfile I used:

from python:3.11-slim

RUN apt-get update && \
    apt-get install -y git && \
    python -m pip install --upgrade pip && \
    pip install -r requirements.txt && \
    pip install pytest-playwright && \
    playwright install-deps && \
    playwright install && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

Yet, upon deploying to Google Cloud Run and initiating the screenshot capture process, I hit a snag:

playwright._impl._api_types.Error: Executable doesn't exist at /home/.cache/ms-playwright/chromium-1084/chrome-linux/chrome
╔═════════════════════════════
║ Looks like Playwright was just installed or updated.                   
║ Please run the following command to download new browsers: 
║                                                                                                            
║     playwright install                                                                          
║                                                                                                            
║ <3 Playwright Team                                                                         
╚═════════════════════════════

Official Playwright Docker Image Saves the Day

Rather than wrestle with the error, I pivoted to an official Docker image of Playwright, and skipped installation of dependency:

mcr.microsoft.com/playwright/python:v1.39.0-jammy

docker image

Let’s dig down the issue:

The Compatibility Issue

Playwright demands compatibility. It officially supports Python versions 3.8 and higher, and it requires specific Linux distributions:

  • Debian 11 (bullseye)
  • Debian 12 (bookworm)
  • Ubuntu 20.04 (focal)
  • Ubuntu 22.04 (jammy)

However, on docker environment, the official image is only based on Unbuntu .

Use ENV PLAYWRIGHT_BROWSERS_PATH

After some search and experiments, I found the only solution in to specify the chromium binary files using ENV PLAYWRIGHT_BROWSERS_PATH during install . source code Dockerfile also use this environment variable to specify the broswer executable path.

using python:3.11-slim-bookworm

FROM python:3.11-slim-bookworm

ENV PLAYWRIGHT_BROWSERS_PATH=/app/ms-playwright
# Turns off buffering for easier container logging
ENV PYTHONUNBUFFERED=1

# Install git
RUN apt-get update

# install playwright or whatever
RUN python -m pip install --upgrade pip && \
    pip install -r requirements.txt

# install chrominum
RUN PLAYWRIGHT_BROWSERS_PATH=/app/ms-playwright && \
    playwright install --with-deps chromium

using ubuntu:22.04

FROM ubuntu:22.04

ENV PLAYWRIGHT_BROWSERS_PATH=/app/ms-playwright
# Turns off buffering for easier container logging
ENV PYTHONUNBUFFERED=1

# Install git
RUN apt-get update && \
    apt-get install -y python3-all python-is-python3 python3-pip

# install playwright or whatever
RUN python -m pip install --upgrade pip && \
    pip install -r requirements.txt

# install chrominum
RUN PLAYWRIGHT_BROWSERS_PATH=/app/ms-playwright && \
    playwright install --with-deps chromium

Memory requirement of Google Cloud Run

The playwright 1.39.0 requires slightly more than 512MB of memory to run on Google Cloud Run. Adjust the memory limit on GCR, as it’s 512 MB by default.

Conclusion

Use the official Docker image to save time, or specify the PLAYWRIGHT_BROWSERS_PATH environment variable on a supported linux docker image.

Further reading: