octoprint-usb-autoconnect

^{_{(Click the picture above for a short demonstration video)}}

Simple bash script (and systemd service) to automatically reconnect the serial connection of OctoPrint using REST whenever the USB cable of the printer is getting plugged in. This is accomplished by a custom udev rule that hooks into the USB subsystem and gets triggered whenever a certain device is found.

Installation

1. On your OctoPrint/OctoPi, clone this repository - make sure you're working as root user:

   sudo su
   git clone https://github.com/frdmn/octoprint-usb-autoconnect /usr/local/src/octoprint-usb-autoconnect
   

2. Obtain your API key from OctoPrint settings, copy and adjust the default configuration file:

   cp /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf.sample /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf
   editor /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf
   

3. Symlink (or copy) script and service:

   ln -s /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect /usr/local/bin/octoprint_usb_autoconnect
   ln -s /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.service /etc/systemd/system/octoprint_usb_autoconnect.service
   

4. Create the udev USB hook:

   editor /etc/udev/rules.d/40-octoprint_usb_autoconnect.rules
   

   ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6001", TAG+="systemd", ENV{SYSTEMD_WANTS}="octoprint_usb_autoconnect.service"
   

   (Please note that the hook above is for an Creality Ender-3, if you have a different printer you can use lsusb and lsusb -vs 00X:00Y to find the proper idVendor and idProduct numbers. See "Find out idVendor / idProduct" for more more detailed guide.)

5. Activate new udev rules and restart service

   udevadm control --reload-rules
   systemctl restart systemd-udevd.service
   

Troubleshooting

Find out idVendor / idProduct

The script was made to work with an Creality Ender 3. In case you have a different printer, you might have to adjust the udev rules to reflect the proper information of your printers USB interface. Follow the steps below to find out the bus and device information of said port:

1. Use lsusb to identify your printer interface:

   pi@octopi:~ $ lsusb
   Bus 001 Device 025: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
   Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
   Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
   Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
   

   I'm going to use my Ender 3 in this example again, so in this case it's the first line in the command output. Write down the bus and device information:

   • Bus: 001
   • Device: 025

2. Display the desired idVendor and idProduct values. Make sure to pass your bus and device information to the -s switch from the previous command:

   pi@octopi:~ $ lsusb -vs 001:025 | grep "idVendor\|idProduct"
   Couldn't open device, some information will be missing
     idVendor           0x0403 Future Technology Devices International, Ltd
     idProduct          0x6001 FT232 USB-Serial (UART) IC
   

   The numberes are prefixed with a 0x to indicate that this is a hex value. You can ignore that and just note down everything that follows:

   • idVendor: 0403
   • idProduct: 6001

3. Now we just need to adjust (or create) the udev rule to reflect the new vendor and product values. Open the /etc/udev/rules.d/40-octoprint_usb_autoconnect.rules file with a text editor of your choice:

   Take a look at step 4 in the installation guide.

Run script manually, verbose mode

pi@octopi:~ $ bash -x /usr/local/bin/octoprint_usb_autoconnect
+ CONFIGFILE=/usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf
+ '[' '!' -f /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf ']'
+ . /usr/local/src/octoprint-usb-autoconnect/octoprint_usb_autoconnect.conf
++ APIKEY=XXX
++ OCTOHOST=http://localhost
+ curl -siL -X POST -H 'X-Api-Key: XXX' -H 'Content-Type: application/json' http://localhost/api/connection -d '{"command":"connect"}'
HTTP/1.1 204 NO CONTENT
Content-Length: 0
X-Robots-Tag: noindex, nofollow, noimageindex
Expires: -1
Pragma: no-cache
Cache-Control: pre-check=0, no-cache, no-store, must-revalidate, post-check=0, max-age=0
X-Clacks-Overhead: GNU Terry Pratchett
Content-Type: text/html; charset=utf-8
pi@octopi:~ $

Run service manually

pi@octopi:~ $ sudo systemctl --no-block start octoprint_usb_autoconnect.service
pi@octopi:~ $

Check udev monitor

Show all events of the USB subsystem:

pi@octopi:~ $ udevadm monitor --subsystem-match=usb
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

[plug in USB device]

KERNEL[4754.758134] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3 (usb)
KERNEL[4754.766885] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0 (usb)
UDEV  [4754.817972] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3 (usb)
UDEV  [4754.821559] add      /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0 (usb)
^C
pi@octopi:~ $

Contributing

1. Fork it
2. Create your feature branch:

git checkout -b feature/my-new-feature

3. Commit your changes:

git commit -am 'Add some feature'

4. Push to the branch:

git push origin feature/my-new-feature

5. Submit a pull request

Requirements / Dependencies

• OctoPrint
• systemd / udev compatible system

Version

1.0.1

License

MIT