How to check if Python is running on an M1 mac, even under Rosetta?

Question

I have python 3.10 code that launches a process but it needs to run a different process if it is running on an M1 Mac.

Is there a way to reliably detect if you are on an M1 Mac even if the python process is running in Rosetta?

I've tried this:

print(sys.platform)

# On Intel silicon:
darwin

# On M1 silicon:
darwin

but it always prints "darwin".

I tried sniffing around in the os.* and sys.* libraries and the best I found was this:

print(os.uname())

# On Intel silicon:
posix.uname_result(sysname='Darwin', nodename='XXX', release='21.5.0', version='Darwin Kernel Version 21.5.0: Tue Apr 26 21:08:22 PDT 2022; root:xnu-8020.121.3~4/RELEASE_X86_64', machine='x86_64')

# On M1 silicon:
posix.uname_result(sysname='Darwin', nodename='XXX', release='21.4.0', version='Darwin Kernel Version 21.4.0: Fri Mar 18 00:47:26 PDT 2022; root:xnu-8020.101.4~15/RELEASE_ARM64_T8101', machine='x86_64')

I assume it returns machine= 'x86_64' on the M1 machine because Python is running in Rosetta? The version field does appear different:

# Intel
version='Darwin Kernel Version 21.5.0: Tue Apr 26 21:08:22 PDT 2022; root:xnu-8020.121.3~4/RELEASE_X86_64'

# M1
version='Darwin Kernel Version 21.4.0: Fri Mar 18 00:47:26 PDT 2022; root:xnu-8020.101.4~15/RELEASE_ARM64_T8101'

Is parsing uname() and looking for "ARM" in the version field the best way to check for M1 silicon if you are running under Rosetta?

Answer 1

Use Python's built-in platform library to determine if a Mac is M1/M2:

import platform

print(platform.processor())

On an M1/M2 Mac --> arm

On an older Mac --> i386