Training with a custom service account needs a new field named service account
trainingInput:
  serviceAccount: CUSTOM_SERVICE_ACCOUNT

https://cloud.google.com/ai-platform/training/docs/custom-service-account


airflow/providers/google/cloud/operators/mlengine.py
#
#
#
"""
This module contains Google Cloud MLEngine operators.
"""
import logging
import re
import warnings
from typing import Dict, List, Optional, Sequence, Union
from airflow.exceptions import AirflowException
from airflow.models import BaseOperator, BaseOperatorLink
from airflow.models.taskinstance import TaskInstance
from airflow.providers.google.cloud.hooks.mlengine import MLEngineHook
from airflow.utils.decorators import apply_defaults
log = logging.getLogger(__name__)
def _normalize_mlengine_job_id(job_id: str) -> str: