Cannot load azure.ml workspace from within a webservice entry_script! Where is the `/var/azureml-app/` located?

I am creating an azure-ml webservice. The following script shows the code for creating the webservice and deploying it locally.

from azureml.core.model import InferenceConfig
from azureml.core.environment import Environment
from azureml.core import Workspace
from azureml.core.model import Model

ws = Workspace.from_config()
model = Model(ws,'textDNN-20News')

ws.write_config(file_name='config.json')

env = Environment(name="init-env")
python_packages = ['numpy', 'pandas']

for package in python_packages:
    env.python.conda_dependencies.add_pip_package(package)

dummy_inference_config = InferenceConfig(
    environment=env,
    source_directory="./source_dir",
    entry_script="./init_score.py",
)

from azureml.core.webservice import LocalWebservice
deployment_config = LocalWebservice.deploy_configuration(port=6789)

service = Model.deploy(
    ws,
    "myservice",
    [model],
    dummy_inference_config,
    deployment_config,
    overwrite=True,
)
service.wait_for_deployment(show_output=True)

As it can be seen, the above code deploys "entry_script = init_score.py" to my local machine. Within the entry_script, I need to load the workspace again to connect to azure SQL database. I do it like the following :

from azureml.core import Dataset, Datastore
from azureml.data.datapath import DataPath
from azureml.core import Workspace

def init():
    pass

def run(data):
  try:
    ws = Workspace.from_config()

    # create tabular dataset from a SQL database in datastore
    datastore = Datastore.get(ws, 'sql_db_name')
    query = DataPath(datastore, 'SELECT * FROM my_table')
    tabular = Dataset.Tabular.from_sql_query(query, query_timeout=10)
    df = tabular.to_pandas_dataframe()

    return len(df)

  except Exception as e:
    output0 = "{}:".format(type(e).__name__)
    output1 = "{} ".format(e)
    output2 = f"{type(e).__name__} occured at line {e.__traceback__.tb_lineno} of {__file__}"
    return output0 + output1 + output2

The try-catch block is for catching the potential exception thrown and return it as an output.

The exception that I keep getting is:

UserErrorException: The workspace configuration file config.json, could not be found in /var/azureml-app or its 
parent directories. Please check whether the workspace configuration file exists, or provide the full path 
to the configuration file as an argument. You can download a configuration file for your workspace, 
via http://ml.azure.com and clicking on the name of your workspace in the right top.

I have actually tried to save the config file by passing an absolute path to the path argument of both ws.write_config(path='my_absolute_path'), and also when loading it to the Workspace.from_config(path='my_absolute_path'), but I got pretty much the same error:

UserErrorException: The workspace configuration file config.json, could not be found in /var/azureml-app/my_absolute_path or its 
parent directories. Please check whether the workspace configuration file exists, or provide the full path 
to the configuration file as an argument. You can download a configuration file for your workspace, 
via http://ml.azure.com and clicking on the name of your workspace in the right top.

Looks like even providing the path does not change the root directory that the entry script starts locating from.

I also tried to directly saving the file to /var/azureml-app/, but this path is not recognized when I passed it to the ws.write_config(path='/var/azureml-app/').

Do you have any idea where exactly is the /var/azureml-app/? Any idea on how to fix this?