jroachgolf84 opened a new pull request, #65103:
URL: https://github.com/apache/airflow/pull/65103
## Description
With AIP-103 adding an interface to persist state for Assets, AIP-93 shifts
more towards implementing a way to use this state when building
`BaseEventTrigger` for "Asset-watching".
Currently, any Trigger defined for "Asset watching" is Asset-unaware. This
PR adds the ability to make these Trigger Asset-aware. The new pattern
implemented here allows for an `Asset` object to be passed to the
`AssetWatcher` (via the `trigger`). This makes much more sense; first, I define
an Asset. Then, I define a way to "watch" that Asset.
```python
from airflow.sdk import Asset, AssetWatcher
from plugins.triggers import GenericEventTrigger
... # Other imports
# Defining the Asset first
random_integer_asset = Asset(name="random_integer_asset")
random_integer_watcher = AssetWatcher(
name="random_integer_watcher",
asset=random_integer_asset, # Passing the Asset to the AssetWatcher
trigger=GenericEventTrigger(
target_number=7,
waiter_delay=30
)
)
with DAG(
dag_id="random_integer_downstream_dag",
start_date=datetime(2026, 1, 1),
schedule=[random_integer_asset]
) as dag:
...
```
## Future State
Eventually, I'd love to get to the following syntax, which is SIGNIFICANTLY
more intuitive for DAG authors.
```python
from airflow.sdk import asset, DAG
... # Other imports
@asset.watcher(
name="random_integer_asset_watcher",
waiter_delay=30
)
def random_integer_asset(target_number):
generated_number: int = random.randint(0, 10)
# Anything "truthy" yields a TriggerEvent and breaks execution
if generated_number == target_number:
return {"generated_number": generated_number}
with DAG(
dag_id="random_integer_downstream_dag",
start_date=datetime(2026, 1, 1),
schedule=[random_integer_asset(7)]
) as dag:
...
```
## Testing
Note, no unit tests have been implemented yet; this PR is just providing a
forum for discussion. Tests will be added after discussion.
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