Implicit exception in `GCSToLocalFilesystemOperator` when reading non-existing files

[shahar1]

Apache Airflow Provider(s)

google

Versions of Apache Airflow Providers

10.15.0

Apache Airflow version

2.6.3

Operating System

Debian

Deployment

Google Cloud Composer

Deployment details

No response

What happened

When using GCSToLocalFilesystemOperator on a non-existing object, the resulted exception is regarding a NoneType object with no size attribute - which is True, but it would be better to raise an exception that the file simply does not exist.

What you think should happen instead

No response

How to reproduce

Use the GCSToLocalFilesystemOperator with a non-existing OBJECT_NAME

    gcs_to_fs = GCSToLocalFilesystemOperator(
        task_id="gcs_to_fs",
        bucket=BUCKET,  # <- exists
        object_name=OBJECT_NAME, # <- does not exist
    )

You'll get an exception similar to this:

Traceback (most recent call last):
  File "/opt/python3.11/lib/python3.11/site-packages/airflow/providers/google/cloud/transfers/gcs_to_local.py", line 118, in execute
    file_size = hook.get_size(bucket_name=self.bucket, object_name=self.object_name)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python3.11/lib/python3.11/site-packages/airflow/providers/google/cloud/hooks/gcs.py", line 968, in get_size
    blob_size = blob.size
                ^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'size'

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

[jsjasonseba]

Hi @shahar1, I’d like to take this issue. I plan to create a custom exception inheriting from AirflowException and raise it. Any suggestions?

[shahar1]

Hi @shahar1, I’d like to take this issue. I plan to create a custom exception inheriting from AirflowException and raise it. Any suggestions?

Thanks for your willing to contribute!
I just assigned you this issue.
I'd avoid for now creating a customized exception class, as no other classes in this provider do so.
Please ping me in the PR when you're ready :)