We usually use the below Python code to get CPU cores:

from multiprocessing import cpu_count
print("CPU cores:", cpu_count())

But when the snippet running inside a docker container, it will just return the number of CPU cores for the physical machine the container runs on, not the actually --cpus (for docker) or CPU limit (for Kubernetes).

Then, how could we get the CPU cores set by docker argument or Kubernetes configuration for this container?

The only answer I could find is here. And the corresponding Python code written by me is:

def get_cpu_limit():
  with open("/sys/fs/cgroup/cpu/cpu.cfs_quota_us") as fp:
    cfs_quota_us = int(fp.read())
  with open("/sys/fs/cgroup/cpu/cpu.cfs_period_us") as fp:
    cfs_period_us = int(fp.read())
  container_cpus = cfs_quota_us // cfs_period_us
  # For physical machine, the `cfs_quota_us` could be '-1'
  cpus = cpu_count() if container_cpus < 1 else container_cpus
  return cpus

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