Awesome
PyChromeless
Python (selenium) Lambda Chromium Automation
PyChromeless allows to automate actions to any webpage from AWS Lambda. The aim of this project is to provide the scaffolding for future robot implementations.
But... how?
All the process is explained here. Technologies used are:
- Python 3.6
- Selenium
- Chrome driver
- Small chromium binary
Requirements
Install docker and dependencies:
make fetch-dependencies
- Installing Docker
- Installing Docker compose
Working locally
To make local development easy, you can use the included docker-compose.
Have a look at the example in lambda_function.py
: it looks up “21 buttons” on Google and prints the first result.
Run it with: make docker-run
Downloading files
If your goal is to use selenium to download files instead of just scraping content from web pages, then
you will need to specify a download_dir
when initializing the WebDriverWrapper. Your download location
should be a writable Lambda directory such as /tmp
. For example, the first code in
lambda_handler
would become
driver = WebDriverWrapper(download_location='/tmp')
This will cause file downloads to automatically download into the download_location
without
requiring a confirmation dialog. You might need to sleep the handler until the file is downloaded
since this occurs asynchronously.
In order to download a file from a link that opens in a new tab (i.e. target='_blank'
) you will need to
call enable_download_in_headless_chrome
in your scraping script after navigating to the desired page, but before
clicking to download. This will replace all target='_blank'
with target='_self'
. For example:
# Navigate to download page
driver._driver.find_element_by_xpath('//a[@href="/downloads/"]').click()
# Enable headless chrome file download
driver.enable_download_in_headless_chrome()
# Click the download link
driver._driver.find_element_by_class_name("btn").click()
Building and uploading the distributable package
Everything is summarized into a simple Makefile so use:
make build-lambda-package
- Upload the
build.zip
resulting file to your AWS Lambda function - Set Lambda environment variables (same values as in docker-compose.yml)
PYTHONPATH=/var/task/src:/var/task/lib
PATH=/var/task/bin
- Adjust lambda function parameters to match your necessities, for the given example:
- Timeout: +10 seconds
- Memory: + 250MB
Shouts to
Contributors
- Jairo Vadillo (@jairovadillo)
- Pere Giro ()
- Ricard Falcó (@ricardfp)