When I try to update or add the label to the bucket using the command "gsutil label ch -l extraKey:extraValue gs://storage-demo-acg-cli" I am getting a BadRequestException: 400 Invalid argument.
Appreciate your help in figuring out the issue with the above command.
Think you need a double quotes around extraKey:extraValue, so "extraKey:extraValue"
I got the same, issue is label cannot contain uppercase characters https://cloud.google.com/resource-manager/docs/creating-managing-labels#requirements
You can only put labels with lowercase characters, for any GCP resource that supports labeling.