Airflow UI link in SlackAPIPostOperator? - slack

Question

Im using SlackAPIPostOperator in Airflow to send Slack messages on task failures.
I wondered if there's a smart way to add a link to the airflow UI logs page of the failed task to the slack message.
The following is an example I want to achieve:
http://myserver-uw1.myaws.com:8080/admin/airflow/graph?execution_date=...&arrange=LR&root=&dag_id=MyDAG&_csrf_token=mytoken
The current message is:
def slack_failed_task(context):
failed_alert = SlackAPIPostOperator(
task_id='slack_failed',
channel="#mychannel",
token="...",
text=':red_circle: Failure on: ' +
str(context['dag']) +
'\nRun ID: ' + str(context['run_id']) +
'\nTask: ' + str(context['task_instance']))
return failed_alert.execute(context=context)

Answer 1

You can build the url to the UI with the config value base_url under the [webserver] section and then use Slack's message format <http://example.com|stuff> for links.
from airflow import configuration
def slack_failed_task(context):
link = '<{base_url}/admin/airflow/log?dag_id={dag_id}&task_id={task_id}&execution_date={execution_date}|logs>'.format(
base_url=configuration.get('webserver', 'BASE_URL'),
dag_id=context['dag'].dag_id,
task_id=context['task_instance'].task_id,
execution_date=context['ts'])) # equal to context['execution_date'].isoformat())
failed_alert = SlackAPIPostOperator(
task_id='slack_failed',
channel="#mychannel",
token="...",
text=':red_circle: Failure on: ' +
str(context['dag']) +
'\nRun ID: ' + str(context['run_id']) +
'\nTask: ' + str(context['task_instance']) +
'\nSee ' + link + ' to debug')
return failed_alert.execute(context=context)

Answer 2

We can also do this using the log_url attribute in the Task Instance
def slack_failed_task(context):
failed_alert = SlackAPIPostOperator(
task_id='slack_failed',
channel="#mychannel",
token="...",
text=':red_circle: Failure on: ' +
str(context['dag']) +
'\nRun ID: ' + str(context['run_id']) +
'\nTask: ' + str(context['task_instance']) +
'\nLogs: <{url}|to Airflow UI>'.format(url=context['task_instance'].log_url)
)
return failed_alert.execute(context=context)
I know this is available since version 1.10.4 at the very least.