I try copying a file to Google Cloud Storage using the command
gsutil cp access.log gs://XXX
and I get
Copying file://access.log [Content-Type=application/octet-stream]...
AccessDeniedException: 403 Access denied.
I would like to know who is the principle who got "access denied". Was it my OS user or the compute engine service account? How can I find this out? The Log Explorer does not seem to know of an "access denied".