Airflow does not create a webserver user when using FAB and logging_level=DEBUG

[bahiaxur]

Apache Airflow version

3.0.1

If "Other Airflow 2 version" selected, which one?

No response

What happened?

I ran into an issue with the Docker image slim-3.0.1-python3.12. After changing the logging_level to DEBUG, I consistently received "invalid credentials" errors when trying to log into the webserver via localhost:8080/.

Upon reviewing the logs from the airflow-init container, I saw the message: "Skipping user creation as auth manager different from Fab is used." This was despite explicitly setting AIRFLOW__CORE__AUTH_MANAGER to airflow.providers.fab.auth_manager.fab_auth_manager.FabAuthManager.

Additionally, the logs showed a BrokenPipeError:

Exception ignored in: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>

BrokenPipeError: [Errno 32] Broken pipe

After some investigation, I discovered the problem stemmed from the entrypoint, specifically within the condition if airflow config get-value core auth_manager | grep -q "FabAuthManager"; then.

The Broken Pipe:

1. airflow, running through log.debug, starts writing output.
2. If grep -q finds 'FabAuthManager' early on in the output stream (or processes enough to know it won't find it, though less common for a broken pipe), it exits.
3. When grep exits, the receiving end of the pipe is closed.
4. If airflow tries to write more data (e.g., more log.debug messages) to that now-closed pipe, the operating system sends a SIGPIPE signal leading to BrokenPipeError.
5. The condition never gets true.
6. The user is not created.

After removing -q from grep the problem was gone.

What you think should happen instead?

User must be created regardless logging_level value. grep command should not exit immediately.

How to reproduce

1. Download the docker-compose.yaml provided by airflow
2. Adjust the env variables to setup the containers
3. set AIRFLOW__LOGGING__LOGGING_LEVEL=DEBUG, _AIRFLOW_WWW_USER_CREATE=True, _AIRFLOW_WWW_USER_USERNAME=airflow and _AIRFLOW_WWW_USER_PASSWORD=airflow
4. run the containers
5. Try to log in the webserver

Operating System

Ubuntu 24.04.2 LTS

Versions of Apache Airflow Providers

apache-airflow-providers-common-compat==1.6.1
apache-airflow-providers-common-io==1.5.4
apache-airflow-providers-common-sql==1.27.0
apache-airflow-providers-smtp==2.0.3
apache-airflow-providers-standard==1.1.0

Deployment

Docker-Compose

Deployment details

docker compose version

Docker Compose version v2.34.0

docker version

Client: Docker Engine - Community
Version: 28.0.4
API version: 1.48
Go version: go1.23.7
Git commit: b8034c0
Built: Tue Mar 25 15:07:16 2025
OS/Arch: linux/amd64
Context: default

Server: Docker Engine - Community
Engine:
Version: 28.0.4
API version: 1.48 (minimum version 1.24)
Go version: go1.23.7
Git commit: 6430e49
Built: Tue Mar 25 15:07:16 2025
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.7.27
GitCommit: 05044ec0a9a75232cad458027ca83437aae3f4da
runc:
Version: 1.2.5
GitCommit: v1.2.5-0-g59923ef
docker-init:
Version: 0.19.0
GitCommit: de40ad0

Anything else?

No response

Are you willing to submit PR?

• [ ]

Code of Conduct

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

[vincbeck]

I am not a system expert but are you suggesting to remove -q from grep?