Airflow set task instance status as skipped programmatically - airflow

Question

I have list that I loop to create the tasks. The list are static as far as size.
for counter, account_id in enumerate(ACCOUNT_LIST):
task_id = f"bash_task_{counter}"
if account_id:
trigger_task = BashOperator(
task_id=task_id,
bash_command="echo hello there",
dag=dag)
else:
trigger_task = BashOperator(
task_id=task_id,
bash_command="echo hello there",
dag=dag)
trigger_task.status = SKIPPED # is there way to somehow set status of this to skipped instead of having a branch operator?
trigger_task
I tried this manually but cannot make the task skipped:
start = DummyOperator(task_id='start')
task1 = DummyOperator(task_id='task_1')
task2 = DummyOperator(task_id='task_2')
task3 = DummyOperator(task_id='task_3')
task4 = DummyOperator(task_id='task_4')
start >> task1
start >> task2
try:
start >> task3
raise AirflowSkipException
except AirflowSkipException as ase:
log.error('Task Skipped for task3')
try:
start >> task4
raise AirflowSkipException
except AirflowSkipException as ase:
log.error('Task Skipped for task4')

Answer 1

yes there you need to raise AirflowSkipException
from airflow.exceptions import AirflowSkipException
raise AirflowSkipException
For more information see the source code

Answer 2

Have a fixed number of tasks to execute per DAG. This is really fine and this is also planning how much max parallel task your system should handle without degrading downstream systems. Also, having fixed number of tasks makes it visible in the web UI and give you indication whether they are executed or skipped.
In the code below, I initialized the list with None items and then update the list with values based on returned data from the DB. In the python_callable function, check if the account_id is None then raise an AirflowSkipException, otherwise execute the function. In the UI, the tasks are visible and indicates whether executed or skipped(meaning there is no account_id)
def execute(account_id):
if account_id:
print(f'************Executing task for account_id:{account_id}')
else:
raise AirflowSkipException
def create_task(task_id, account_id):
return PythonOperator(task_id=task_id,
python_callable=execute,
op_args=[account_id])
list_from_dbhook = [1, 2, 3] # dummy list. Get records using DB Hook
# Need to have some fix size. Need to allocate fix resources or # of tasks.
# Having this fixed number of tasks will make this tasks to be visible in UI instead of being purely dynamic
record_size_limit = 5
ACCOUNT_LIST = [None] * record_size_limit
for index, account_id_val in enumerate(list_from_dbhook):
ACCOUNT_LIST[index] = account_id_val
for idx, acct_id in enumerate(ACCOUNT_LIST):
task = create_task(f"task_{idx}", acct_id)
task