eladkal opened a new issue, #35381:
URL: https://github.com/apache/airflow/issues/35381
### Body
Notifiers is a really cool feature. I have been using it for a while and
it's simplify the use case for writing callable functions for alerts.
But... it has also one big drawback.
When I do:
`BashOperator(task_id="mytask",bash_command="fail",on_failure_callback=SmtpNotifier(...))`
i must implement on my own the logic for the message. In the case of Smtp
that would be the `title` and the `html_content` for this message. As you may
expect this is "pretty static" and include information about the failing
dag_id/task_id, traceback of the error and link to the log. This is why
probably most users do.
```
BashOperator(
task_id="mytask",
bash_command="fail",
on_failure_callback=SmtpNotifier(
subject="The task {{ ti.task_id }} failed",
html_content=
"""
"Try {{ti.try_number}} out of {{ti.max_tries + 1}}<br>"
"Log: <a href="{{ti.log_url}}">Link</a><br>'
"Host: {{ti.hostname}}<br>"
'Mark success: <a href="{{ti.mark_success_url}}">Link</a><br>'
"""
)
)
```
This makes the notifier code very very big (same goes for
`on_retry_callback` / `on_success_callback`)
Thus some users may decide to subclass the notifier and create
`FailureSmtpNotifier`, `SuccessSmtpNotifier`, `RetrySmtpNotifier`
For example:
```
class MySmtpNotifier(SmtpNotifier):
def __init__(
self,
to:str,
from_email='[email protected]'
):
super().__init(to=to, from_email=from_email, subject='',
html_content='')
def notify(self, context):
task_instance = context["task_instance"]
self.subject = f"airflow dag {task_instance.dag_id} has failed"
self.html_content= """
"Try {{ti.try_number}} out of {{ti.max_tries + 1}}<br>"
"Log: <a href="{{ti.log_url}}">Link</a><br>'
"Host: {{ti.hostname}}<br>"
'Mark success: <a
href="{{ti.mark_success_url}}">Link</a><br>'
"""
super().notify(context)
```
Then on usage user needs to provider only the to parameter:
`BashOperator(task_id="mytask",bash_command="fail",on_failure_callback=MySmtpNotifier(to="[email protected]"))`
but that also is not very nice. It requires users to write this class in
their own deployment and have at least 3 subclasses per each notifier.
**My proposal:**
We should provide presets for failure/success/retry for each notifier. Users
may use the preset if they want.
To give an example - we have `email_on_success`, `email_on_failure`,
`email_on_retry` that users can set in BaseOperator (these existed from the
days of airflow 1.8?) their template can be the exact template for
`SmtpNotifier` and for other notifiers we can author templates.
The choice between templates may be provided by a simple mode parameter for
example `SmtpNotifier(mode=failure)` or maybe by checking the parameter it was
used with `on_failure_callback=SmtpNotifier()` obviously mean mode=failure
### Committer
- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow
project.
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