Airflow KubernetesPodOperator : how to access secret passed to Pod?

Question

I am trying to pass secret variables to my KubernetesPodOperator in airflow

Here is what I have done :

1. Create a secret.yaml file that looks like the following

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
type: Opaque
data:
  SECRET_1: blabla 
  SECRET_2: blibli 

2. Apply the secret :

kubectl apply -f ./secret.yaml

3. Retrieve the secret from my DAG file :

from airflow.contrib.kubernetes.secret import Secret
from airflow.contrib.operators.kubernetes_pod_operator import KubernetesPodOperator
from airflow.models import DAG

SECRET_1 = Secret(
   deploy_type="env", deploy_target="SECRET_1", secret="ai-controller-object-storage", key="SECRET_1"
)
SECRET_2 = Secret(
   deploy_type="env", deploy_target="SECRET_2", secret="ai-controller-object-storage", key="SECRET_2"
)

with DAG(...) as dag:
   KubernetesPodOperator(
           task_id=..,
           trigger_rule="all_success",
           namespace="default",
           image=IMAGE,
           startup_timeout_seconds=600,
           secrets=[
               SECRET_1,
               SECRET_2], ...)

So now as I understand, I should access SECRET_1 as environnement variable in my container from KubernetesPodOperator

However my first task from a python script (with os.environ["SECRET_1"]) returns an error that indicates that this environment variable does not exist :

KeyError: 'SECRET_1'

How can I access this variable from my python script then ?