This is a simple command line application that displays the power draw of an NVIDIA GPU over time.
YouTube video where I use this to give a live demo: https://youtu.be/aZoD-jgO3fE?t=747
If you need to programmatically measure GPU energy, check out the Zeus framework. ZeusMonitor is built for that.
This application requires NVML (libnvidia-ml.so) on your system. It comes together with the CUDA toolkit.
The Python package nvidia-ml-py is merely a wrapper of the library and will fail if it cannot find libnvidia-ml.so on your system.
$ pip install nvidia-ml-py
$ python power_monitor.py