Python: Symmetric Encryption with GPG and Subprocess

I'm trying to achieve the functionality provided by the following bash command in Python.

echo "$DATA" | gpg --symmetric --armor --batch --passphrase "${KEY}"

So far I've tried to use subprocess but am having difficulty passing in the data. I tried giving it as a command in the list of parameters to send to subprocess but that just effectively echos the the entire thing.

cmd = f"| gpg --symmetric --armor --batch --passphrase {key}".split()                                                  
temp = ["echo", f"\"{data}\""]
temp.extend(cmd)                                                                                                                      
res = subprocess.run(temp, stdout=subprocess.PIPE, universal_newlines=True)                                                          
encrypted = res.stdout.strip()

I'm also interested in using the python-gnupg module but have not yet figured out how to replicate the above with it either.

Thanks in advance for any help!

Solution

You can use the input argument to run()/check_output():

from getpass import getpass
import subprocess

key = getpass("KEY: ")
data = b'Symmetric Encryption with GPG and Subprocess'
command = ["gpg", "--symmetric", "--armor", "--batch", "--passphrase", key]

out = subprocess.check_output(command, input=data, universal_newlines=False)

Note that GNU echo will, by default, append a newline. Use echo -n to not print the trailing \n. Either way, you'll want to be careful to mimic this in Python.