DiscordNotifier return bad request when using Airflow 3.2.0

[datateamFrontier]

Under which category would you file this issue?

Providers

Apache Airflow version

3.2.0

What happened and how to reproduce it?

We encounter discord notification failure after upgrading from Airflow 3.1.7 to 3.2.0 without changing the configuration. We usually use this feature for failure report.

This is our dag for testing

import pendulum
from airflow.sdk import dag, task

from airflow.providers.discord.notifications.discord import DiscordNotifier


# Definisi DAG dengan TaskFlow API
@dag(
    dag_id="testing",
    start_date=pendulum.parse("2025-11-08T00:00:00+07:00"),
    end_date=pendulum.parse("2026-04-20T17:00:00+07:00"),
    schedule=None,
    catchup=False,
    max_active_runs=1,
    default_args={
        'on_failure_callback':  DiscordNotifier(
            discord_conn_id = 'discord_connection',
            text = 'testing',
        ),
    },

)
def testing():

    @task
    def task1():
        print('testing task 1')
        return

    @task
    def task2():
        print(1 + 'testing task 2')
        return

    task1() >> task2()

testing()

This is the log

::group::Log message source details sources=["/opt/airflow/logs/dag_id=testing/run_id=manual__2026-04-15T02:25:04.465800+00:00/task_id=task2/attempt=1.log"] 
::endgroup::
[2026-04-15T02:25:06.212451Z] INFO - DAG bundles loaded: dags-folder
[2026-04-15T02:25:06.212926Z] INFO - Filling up the DagBag from /opt/airflow/dags/testing.py
[2026-04-15T02:25:06.293095Z] ERROR - Task failed with exceptionTypeError: unsupported operand type(s) for +: 'int' and 'str'
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/execution_time/task_runner.py, line 1263 in run
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/execution_time/task_runner.py, line 1678 in _execute_task
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/bases/operator.py, line 443 in wrapper
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/bases/decorator.py, line 397 in execute
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/bases/operator.py, line 443 in wrapper
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/standard/operators/python.py, line 227 in execute
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/standard/operators/python.py, line 250 in execute_callable
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/execution_time/callback_runner.py, line 97 in run
    File /opt/airflow/dags/testing.py, line 38 in task2

[2026-04-15T02:25:06.770837Z] ERROR - HTTP error: Bad Request
[2026-04-15T02:25:06.770945Z] ERROR - Bad Request
[2026-04-15T02:25:06.771441Z] ERROR - Failed to send notification (sync): 400:Bad Request
[2026-04-15T02:25:06.771499Z] ERROR - Failed to run task callback kind=on_failure_callback  index=0  callback=<airflow.providers.discord.notifications.discord.DiscordNotifier object at 0x7f7ff80b5160> AirflowException: 400:Bad Request
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/execution_time/task_runner.py, line 1544 in _run_task_state_change_callbacks
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/execution_time/callback_runner.py, line 97 in run
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/sdk/bases/notifier.py, line 138 in __call__
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/discord/notifications/discord.py, line 108 in notify
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/discord/hooks/discord_webhook.py, line 236 in execute
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/http/hooks/http.py, line 300 in run
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/http/hooks/http.py, line 351 in run_and_check
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/http/hooks/http.py, line 315 in check_response
,HTTPError: 400 Client Error: Bad Request for url: https://discord.com/api/webhooks/xxxxxxxx/yyyyyyyy
    File /home/airflow/.local/lib/python3.13/site-packages/airflow/providers/http/hooks/http.py, line 311 in check_response
    File /home/airflow/.local/lib/python3.13/site-packages/requests/models.py, line 1028 in raise_for_status

What you think should happen instead?

We refer to this documentation since Airflow 3.1.7 and no problem encountered. This problem occur after upgrading to 3.2.0.

Operating System

Ubuntu 24.04

Deployment

Docker-Compose

Apache Airflow Provider(s)

discord

Versions of Apache Airflow Providers

3.12.2

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?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[potiuk]

marked it as good first issue for someone to take a look. You can always downgrade provider to one of the previous versions (looking at the changelog) - the docs have information about those - indivfdually downgrading/upgrading providers and extending image if needs be.

[potiuk]

It would be great actually - and help someone if you see which version of the provider introduces the issue. It might also be http provider to downgrade as Discord is based on Http one.

Woudl be really good to bi-sect to see which version introduced it.

[1cadumagalhaes]

Hey!
Ran into this bug today as well.

=== With webhook_endpoint in extra ===
Method: POST
URL: https://discord.com/api/webhooks/123/token
Headers:
  User-Agent: python-requests/2.33.1
  Accept-Encoding: gzip, deflate
  Accept: */*
  Connection: keep-alive
  webhook_endpoint: webhooks/123/token
  Content-type: application/json
  Content-Length: 56
Body: {"content": "test", "username": "Airflow", "tts": false}

=== Without webhook_endpoint in extra ===
Method: POST
URL: https://discord.com/api/webhooks/123/token
Headers:
  User-Agent: python-requests/2.33.1
  Accept-Encoding: gzip, deflate
  Accept: */*
  Connection: keep-alive
  Content-type: application/json
  Content-Length: 56
Body: {"content": "test", "username": "Airflow", "tts": false}

Looks like this version of the HttpHook is injecting the information from extra fields as headers in the request, which made discord reject it as a bad request.

Removing the extra fields in the connection and passing webhook_endpoint to the Webhook Hook or operator should make it work for now.

I might get some time to take a look into the providers, if no one else shows interest