import json import os with open('/config/servers.json', 'w') as f: print("created " + f.name) template_string = '{"Servers": {"1": {"Name": "DavinciResolve", "Group": "Servers", "Port": 5432, "Username": "postgres", "Host": "postgres", "SSLMode": "prefer", "MaintenanceDB": "postgres"}}}' data = json.loads(template_string) data["Servers"]["1"]["Username"]=os.getenv("POSTGRES_USER") print(data) json.dump(data, f, indent=2)