Unable to read Intel RAPL files for CPU power : Permission denied

Description

Due to a security issue all Linux distributions are changing right permission of the RAPL file, used by Code Carbon for CPU power. After updating the file could be read only by root.

There is a workaround, thanks to https://github.com/prometheus/node_exporter/issues/1892 :

1. sudo apt install sysfsutils
2. Add this line in /etc/sysfs.conf : mode class/powercap/intel-rapl:0/energy_uj = 0444
3. reboot

Without rebooting you could do sudo chmod -R a+r /sys/class/powercap/intel-rapl but it will be lost at next boot.

But you need root access to do this. Following https://github.com/mlco2/codecarbon/issues/232 that has been closed by a PR that reduce errors logs, I create this issue to find a workaround that don't need to be root.

We could use the CPU load and apply it to the CPU TDP, but it is not so simple as shown here https://medium.com/teads-engineering/estimating-aws-ec2-instances-power-consumption-c9745e347959

Start by reproducing the Linux Intel RAPL permission-denied behavior described in the issue and reading linked issue #232 and the node_exporter discussion. Done means identifying a viable workaround that allows CPU power measurement without requiring root; no source file or test is named, so the implementation scope needs investigation.