2026-07-02T10:33:27.403495Z [error ] Exception in ASGI application
[uvicorn.error] loc=httptools_impl.py:426
Traceback (most recent call last):
File "/usr/python/lib/python3.10/site-packages/uvicorn/protocols/http/httptools_impl.py", line 421, in run_asgi
result = await app( # type: ignore[func-returns-value]
File "/usr/python/lib/python3.10/site-packages/fastapi/applications.py", line 1159, in __call__
await super().__call__(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/applications.py", line 90, in __call__
await self.middleware_stack(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/errors.py", line 186, in __call__
raise exc
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/errors.py", line 164, in __call__
await self.app(scope, receive, _send)
File "/opt/airflow/airflow-core/src/airflow/api_fastapi/common/http_access_log.py", line 109, in __call__
await self.app(scope, receive, capture_send)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 29, in __call__
await responder(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 130, in __call__
await super().__call__(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 46, in __call__
await self.app(scope, receive, self.send_with_compression)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/base.py", line 193, in __call__
response = await self.dispatch_func(request, call_next)
File "/opt/airflow/airflow-core/src/airflow/api_fastapi/auth/middlewares/refresh_token.py", line 68, in dispatch
response = await call_next(request)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/base.py", line 168, in call_next
raise app_exc from app_exc.__cause__ or app_exc.__context__
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/base.py", line 144, in coro
await self.app(scope, receive_or_disconnect, send_no_error)
File "/usr/python/lib/python3.10/site-packages/starlette/middleware/exceptions.py", line 63, in __call__
await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
raise exc
File "/usr/python/lib/python3.10/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
await app(scope, receive, sender)
File "/usr/python/lib/python3.10/site-packages/fastapi/middleware/asyncexitstack.py", line 18, in __call__
await self.app(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/routing.py", line 660, in __call__
await self.middleware_stack(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/routing.py", line 680, in app
await route.handle(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/routing.py", line 276, in handle
await self.app(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/fastapi/routing.py", line 134, in app
await wrap_app_handling_exceptions(app, request)(scope, receive, send)
File "/usr/python/lib/python3.10/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
raise exc
File "/usr/python/lib/python3.10/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
await app(scope, receive, sender)
File "/usr/python/lib/python3.10/site-packages/fastapi/routing.py", line 120, in app
response = await f(request)
File "/usr/python/lib/python3.10/site-packages/fastapi/routing.py", line 695, in app
content = await serialize_response(
File "/usr/python/lib/python3.10/site-packages/fastapi/routing.py", line 306, in serialize_response
return serializer(
File "/usr/python/lib/python3.10/site-packages/fastapi/_compat/v2.py", line 231, in serialize_json
return self._type_adapter.dump_json(
File "/usr/python/lib/python3.10/site-packages/pydantic/type_adapter.py", line 677, in dump_json
return self.serializer.to_json(
pydantic_core._pydantic_core.PydanticSerializationError: Error serializing to JSON: ValidationError: 1 validation error for ValidatorIterator
0.interval
Input should be a valid number [type=float_type, input_value={'__classname__': 'dateti..._': 2, '__data__': 10.0}, input_type=dict]
For further information visit https://errors.pydantic.dev/2.13/v/float_type
from airflow.sdk import dag, task
from airflow.sdk.definitions.deadline import (
SyncCallback,
AsyncCallback,
DeadlineAlert,
DeadlineReference,
)
from datetime import timedelta
async def custom_async_callback(**kwargs):
"""Handle deadline violation with custom logic."""
print(f"Deadline exceeded for Dag {kwargs.get('dag_id')}!")
print(f"Alert type: {kwargs.get('alert_type')}")
def sync_callback(**kwargs):
"""Handle deadline violation with custom logic."""
print(f"Deadline exceeded for Dag {kwargs.get('dag_id')}!")
print(f"Alert type: {kwargs.get('alert_type')}")
@dag(
deadline=DeadlineAlert(
reference=DeadlineReference.DAGRUN_QUEUED_AT,
interval=timedelta(seconds=10),
callback=SyncCallback(
sync_callback,
kwargs={"alert_type": "time_exceeded", "dag_id": "deadline_alerts_sync_callback"},
),
),
)
def deadline_alerts_sync_callback():
@task
def print_hello():
import time
time.sleep(15)
print("Hello, World!")
print_hello()
deadline_alerts_sync_callback()
@dag(
deadline=DeadlineAlert(
reference=DeadlineReference.DAGRUN_QUEUED_AT,
interval=timedelta(seconds=10),
callback=AsyncCallback(
custom_async_callback,
kwargs={"alert_type": "time_exceeded", "dag_id": "deadline_alerts_async_callback"},
),
),
)
def deadline_alerts_async_callback():
@task
def print_hello():
import time
time.sleep(15)
print("Hello, World!")
print_hello()
deadline_alerts_async_callback()
Under which category would you file this issue?
Airflow Core
Apache Airflow version
v3-3-test
What happened and how to reproduce it?
I was looking for the deadline alerts UI additions described in #62195 and could not find them. Inspecting the page I see 500 errors relating on
GET /ui/dags/{dag_id}/deadlineAlerts:The API server logs show a pydantic serialization error:
The deadlines show up correctly as missed in the main deadlines list:
My two example Dags:
Repro:
What you think should happen instead?
The UI additions from #62195 should be visible.
Operating System
macOs Tahoe 26.5.1
Deployment
Other
Apache Airflow Provider(s)
No response
Versions of Apache Airflow Providers
No response
Official Helm Chart version
Not Applicable
Kubernetes Version
No response
Helm Chart configuration
No response
Docker Image customizations
No response
Anything else?
No response
Are you willing to submit PR?
Code of Conduct