Availability Bot
A Python bot that checks a list of sites for product availability and sends alerts via webhooks (e.g. Discord or Slack).
Usage
- Clone this repository
- Set the WEBHOOK_ALERT and WEBHOOK_PULSE environment variables (using Slack, or Discord)
- Download a browser driver compatible with the one you have installed here
- Edit the bot.py script changing the web driver's path to the one you downloaded
- Install Python 3
- Install the requirements:
pip install -r requirements.txt - Run the script:
./bot.sh
Context
NVidia's RTX 30 series cards were released mid-2020, during the COVID-19 pandemic. For that reason, supply chains were slow and demand for home-office hardware rose up, resulting in very low stock available for those items. In the mentioned stores, we had something like 5 units per week, made available at random hours during the days. To release me from constantly pressing F5 in these stores' GPU sections, I made this bot.
How it works
This bot uses Selenium to launch a Chrome instance, access the pages I configured and look for a "buy" button. If the button is found, it plays a sound (in case I'm not using the computer; e.g. Kabum updates it's stock at 3 a.m. every day) and sends a message to my Slack notifications channel, which then vibrates my smartwatch.
As many other websites, these stores try to identify and block bots. As a workaround, I removed the automation flag from the Selenium driver's request headers and a new UserAgent header is generated at every loop iteration. I also added a random sleep time between requests and used the same browser instance to access sequentially all the stores, so the history is carried (in case any store checks it). I opted to use the actual browser instance in case a Captcha was required, so I could solve it manually before the bot could loop indefinitely (Terabyteshop asks the user to solve a Captcha only once in a session).
Even with all the workarounds, the loop may still fail for some unknown (to me) reason. When this happens, a browser instance may be left open and blow up the memory if it repeats this behavior too much. To address this I added a graceful exit procedure that, combined with a timeout method, allows the script to cleanly exit. I also wrapped the python script execution with a shell script that loops restarting the process if it exits unexpectedly.
Finally, the bot also sends a "pulse" to slack (in a silenced channel) to indicate that it is still running. I added this after I lost a chance to buy a card due to an uncaught timeout crash in the first day.
Conclusion
This bot actually helped me buy the card I wanted for a fair price in 2020 :)