Is the singularity environment preserved for Python's subprocess?

Question

I am working on a Python program and I wish to use Python's subprocess's run/Popen functions. I am working on a singularity environment and I found the following post which asks somewhat of a similar question but was left unanswered. I am running the Python from a singularity environment, is it preserved for the subprocesses?

Answer 1

Yes, when you run Python's subprocess functions from within a Singularity container, the subprocesses inherit the same container environment by default.

Here's an example to demonstrate this:

import subprocess
import os

# Print the current Python interpreter path (should be inside Singularity)
print("Parent process Python: ", sys.executable)

# Print some environment variable to confirm we're in Singularity
print("SINGULARITY_CONTAINER:", os.environ.get("SINGULARITY_CONTAINER", "Not in Singularity"))

# Run a subprocess and check its environment
result = subprocess.run(["which", "python"], capture_output=True, text=True)
print("Subprocess found Python at:", result.stdout.strip())

# Run another subprocess to confirm we're still in the same environment
env_result = subprocess.run(["printenv", "SINGULARITY_CONTAINER"], 
                           capture_output=True, text=True)
print("Subprocess Singularity env:", env_result.stdout.strip())