Combine Let's Encrypt certificate files to a fully combined PEM certificate that is compatible with LiveConfig

combine-certificates.py

import argparse

parser = argparse.ArgumentParser(description='Combines Let\'s Encrypt certificate to a fully PEM certificate file to use with LiveConfig.')
parser.add_argument('private_key', action='store', help='Path to private key file')
parser.add_argument('full_chain', action='store', help='Path to full chain certificate file')
parser.add_argument('output', action='store', help='Output file for combined PEM certificate')

args = parser.parse_args()

try:
    a = open(args.private_key)
except Exception as e:
    print("Error: Could not read private key file. Does the file exist and do you have sufficient rights to read from this file?")
    exit(1)

try:
    b = open(args.full_chain)
except Exception as e:
    print("Error: Could not read full chain certificate file. Does the file exist and do you have sufficient rights to read from this file?")
    exit(1)

try:
    c = open(args.output, "w")
except Exception as e:
    print("Error: Could not create output file. Do you have sufficient rights to write in target directory?")
    exit(1)

try:
    private_key = a.read()
    full_chain = b.read()
except Exception as e:
    print("Error: Could not read private key or full chain certificate file. Are the files existant and readable?")
    exit(1)

combined = private_key + full_chain

try:
    c.write(combined)
except Exception as e:
    print("Error: Could not write into output file. Do you have sufficient rights to write into target file?")
    exit(1)

print("Successfully wrote combined PEM certificate file.")
exit(0)