This update removes the need for the tmsh script on BIG-IP by using the options query parameter to pass the record data directly to the tmsh command. This removes complexity and should be preferred over the previous solution.

dgmgmt_update.py

###################################################################################
# dgmgmt.py
#
# author: jason rahm
#
# usage: dgmgmt.py [-h] host user {add,modify,delete} datagroup dgvalues
#
# positional arguments:
#   host                 BIG-IP IP/FQDN
#   user                 BIG-IP Username
#   {add,modify,delete,replace}  add | modify | delete | replace-all-with
#   datagroup            Data-Group name you wish to change
#   dgvalues             Key or KV Pairs, in this format: "k1,k2,k3=v3,k4=v4,k5"
#
# optional arguments:
#   -h, --help           show this help message and exit
###################################################################################

from bigrest.bigip import BIGIP
# from pprintjson import pprintjson as ppjson
import argparse
import getpass
import sys


def build_parser():
    parser = argparse.ArgumentParser()
    parser.add_argument("host", help="BIG-IP IP/FQDN")
    parser.add_argument("user", help="BIG-IP Username")
    parser.add_argument(
        "action",
        help="add | modify | delete",
        choices=["add", "modify", "delete", "replace-all-with"],
    )
    parser.add_argument("datagroup", help="Data-Group name you wish to change")
    parser.add_argument(
        "dgvalues", help='Key or KV Pairs, in this format: "k1,k2,k3=v3,k4=v4,k5"'
    )
    return parser.parse_args()


def format_records(action, records):
    # records action { key1 key2 { data value2 } key3 key4 }
    recs = ""
    for record in records.split(","):
        x = record.split("=")
        record_key = x[0]
        if len(x) == 1 and action != "modify":
            recs += f"{record_key} "
        elif len(x) == 1 and action == "modify":
            recs += f'{record_key} {{ data "" }} '
        elif len(x) == 2:
            record_value = x[1]
            recs += f'{record_key} {{ data "{record_value}" }} '
        else:
            raise ValueError("Max record items is 2: key or key/value pair.")
    return f"records {action} {{ {recs} }}"


def instantiate_bigip(host, user):
    pw = getpass.getpass(prompt=f"\n\tWell hello {user}, please enter your password: ")
    try:
        obj = BIGIP(host, user, pw)
    except Exception as e:
        print(f"Failed to connect to {args.host} due to {type(e).__name__}:\n")
        print(f"{e}")
        sys.exit()
    return obj


def dg_update(bigip, dgname, dgaction, dgvalues):
    if not bigip.exist(f"/mgmt/tm/ltm/data-group/internal/{dgname}"):
        print(
            f"\n\tThe {dgname} data-group doesn't exist. Please specify an existing data-group.\n"
        )
        sys.exit()
    else:
        record_data = format_records(dgaction, dgvalues)

    try:
        return bigip.modify(
            f"/mgmt/tm/ltm/data-group/internal/{dgname}?options={record_data}", {}
        )
    except Exception as e:
        print(f"Failed to modify the data-group due to {type(e).__name__}:\n")
        print(f"{e}")
        sys.exit()


if __name__ == "__main__":
    args = build_parser()
    b = instantiate_bigip(args.host, args.user)
    result = dg_update(b, args.datagroup, args.action, args.dgvalues)
    # ppjson(result.properties.get("records"))
    print(result.properties.get("records"))