setup/convert_creds.py

import json
import base64
import os
import dotenv

# load the service account key
with open(os.getcwd() +'/gcp_default_creds.json') as f:
    service_key = json.load(f)

dotenv_file = dotenv.find_dotenv()
dotenv.load_dotenv(dotenv_file)

# convert json to a string
service_key = json.dumps(service_key)

# encode service key
encoded_service_key = base64.b64encode(service_key.encode('utf-8'))
encoded_service_key = str(encoded_service_key)[2:-1]

print(encoded_service_key)
# b'many_characters_here'
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = encoded_service_key
print(os.environ['GOOGLE_APPLICATION_CREDENTIALS'])  # outputs 'newvalue'

# Write changes to .env file.
dotenv.set_key(dotenv_file, "GOOGLE_APPLICATION_CREDENTIALS", os.environ["GOOGLE_APPLICATION_CREDENTIALS"])