Error copying pip.conf from bucket to Cloud Composer Airflow environment - google-cloud-storage

Question

Similar to this lonely questioner I'm trying to install a Python package from a private PyPI repo such that it's available to our Google Cloud Composer Airflow instance.
I've followed these instructions but Airflow continues not to know about my package:
No module named 'foopackage'
I can't find any reference to my pip.conf in any logs anywhere so I'm not sure whether the file is in the right place, or has the right contents.
How can I proceed with debugging this problem?
The Cloud Composer environment logs show that there was a problem with copying pip.conf from the bucket, but don't give any other details:
{
insertId: "16qa4c8g540zxs3"
logName: "projects/{my-env}/logs/composer-agent"
receiveTimestamp: "2020-02-06T15:59:03.164564368Z"
resource: {…}
severity: "ERROR"
textPayload: "Copying gs://{my-bucket}/config/pip/pip.conf...
"
timestamp: "2020-02-06T15:59:00.857642186Z"
}
I first thought this might be a permissions issue, but the file seems to have the same set of permissions as other files in this bucket.
Where can I get more detailed information on what went wrong when copying that file?
update
I'm on composer-1.7.2-airflow-1.10.2.
update
The service account for my Composer environment already has the project.editor role.

Answer 1

This is an indicator that the Docker image used for the web server failed to build. To find the root cause, please view Cloud Build logs in project.
The reason for this, is a failed or taking long time operation, it timed out on the Composer’s backend. In some cases these errors persist in the backend, blocking future attempts. You can try re-enabling the API:
First solution that comes to my mind is running following commands in cloud shell:
gcloud services disable composer.googleapis.com
gcloud services enable composer.googleapis.com
After enabling the API, please update your Composer environment as usual.
When you install packages, the Composer environment re-creates Docker containers for the Airflow workers and scheduler, then performs a rolling update within the GKE cluster to update the workers to keep workers available. You can check Kubernetes Engine > Workloads to see if your environment timed out because of waiting for the scheduler and workers to come back online.
When Composer environment is using a custom service account and does not have IAM access to use Cloud Build, builds will fail immediately, so please check it. You can diagnose these by going to Cloud Build > History, and when you see builds without a log, it means that builds failed even before trying to build a container.
When your package implement bindings, it will fail at runtime if the libraries don't exist on the system. This means it is incompatible with Cloud Composer, because getting shared libraries into the build environment is not currently supported.
Another thing, make sure if your project is packed in correct way.
I hope you find the above pieces of information useful.