"Bad Request-Error" when trying to connect to Azure Data Lake with Airflow - airflow

Question

I try to connect to Azure Data Lake using Airflow. I use Airflow connection via the Web UI.
When I try to connect using the test button, I get an error Bad Request. As seen below
I use the correct UUIDs. These UUIDs have been verified in other cases. I also checked the firewall.
When I execute the DAG, I use the Azure Data Lake connection id to check if a file exists: If I apply the method as described here: What is the best way to check if a file exists on an Azure Datalake using Apache Airflow?
This is the error I get
[2022-05-06, 17:27:33 UTC] {log.py:127} ERROR - 99ec1d77-e91c-4fd3-a1c7-fa751ca1e779 - OAuth2Client:The token response from the server is unparseable as JSON: ***
Traceback (most recent call last):
File "/opt/airflow/lib/python3.8/site-packages/adal/oauth2_client.py", line 168, in _validate_token_response
wire_response = json.loads(body)
File "/usr/lib/python3.8/json/init.py", line 357, in loads
return _default_decoder.decode(s)
File "/usr/lib/python3.8/json/decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib/python3.8/json/decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 3 column 1 (char 4)
[2022-05-06, 17:27:33 UTC] {log.py:127} ERROR - 99ec1d77-e91c-4fd3-a1c7-fa751ca1e779 - OAuth2Client:Error validating get token response: ***
Traceback (most recent call last):
File "/opt/airflow/lib/python3.8/site-packages/adal/oauth2_client.py", line 238, in _handle_get_token_response
return self._validate_token_response(body)
File "/opt/airflow/lib/python3.8/site-packages/adal/oauth2_client.py", line 168, in _validate_token_response

Answer 1

Authenticating to Azure Data Lake is by token credentials i.e. add specific credentials (client_id, secret, tenant) and account name to the Airflow connection.
Information about how to set it up can be found in this doc.
You can see code example in the source code test function.
Other method of authentication are currently not supported.

Answer 2

I was trying to get the connection running using the Airflow implementation. My impression was that it was buggy and did not work out well. The above situation happened with Airflow 2.2.5. When I upgraded to Airflow 2.3.0, the test button was grayed out.
The final solution was to use Access Tokens instead.