Install and run

Tested on a raspbian system with the following extra stuff

• Node.js version 7.10.1
• apt install build-essential libsystemd-dev

1. Copy the source code to /opt/vending
2. Build the nfcreader daemon with cd nfcreader && make
3. Copy the systemd service file(s) to /etc/systemd/system
4. Set environment variables in the newly copied service file
5. Reload systemd daemon systemctl daemon-reload
6. Start service systemctl start vending
7. See log output journalctl -fu vending

Notes

Watchdog

The systemd service is of Type=notify, which means that it expects calls to sd_notify within the specified timeout of WatchdogSec.

The bin/vend.js script spawns an instance of nfcreader which takes care of these calls to keep the watchdog happy. This decision was made after suspicions that the nfcreader script is deadlocking and needs an occasional restart due to possible hardware issues.

Hence, whenever the card reader daemon dies, the program is restarted thanks to Restart=always.

A thing to be aware of is that the nfcreader will block until a tag that has been read is removed from the reader again. If the tag is not removed within the watchdog time limit, the process will restart due to missed ping events.