Simple Klipper Power Loss Recovery

I am currently working on a more complex approach of Power Loss Recovery, but while working on that, I made this simple power loss recovery script in Python, that can recover any print by the last recorded Z height. It works as follows:

1. Slicer's start G-Code ends with ; POWER_PANIC_PRESERVE
2. Slicer's layer change G-Code will invoke UPDATE_Z Z= to set the z height
3. UPDATE_Z will save the variable to variables.cfg
4. When power is lost, you still have to manually heat up the bed
5. You can get the last recorded z from variables.cfg
6. Run the script: python3 /path/to/script.py <Z HEIGHT FROM PREVIOUS STEP> <NAME OF GCODE FILE>
7. Look in your G-Codes folder, and there should be a G-Code file that starts with RECOVER-SOFT-
8. Use SET_KINEMATIC_POSITION Z= to set the z height without homing Z
9. Use the move panel to move Z 10mm up
10. Run G28 X Y to home X and Y
11. For now, you will still need to edit your recovered G-Code to remove any homing G-Code from the start G-Code.
12. Set your velocity limit to something slow e.g. 20mm
13. Start the recovery G-Code and make sure your print doesn't fall off the bed.
14. Increase print speed slowly to avoid knocking the print off the bed.

Config

Python Script

Add the following to the end of your slicer's start G-Code (NOT in your PRINT_START macro if you have one)

; POWER_PANIC_PRESERVE

Add the following to your slicer's after layer change G-Code (this syntax is for PrusaSlicer)

UPDATE_Z Z=[layer_z]

If anyone finds this helpful or has ideas to improve it, please let me know here.