Vault Agent Auto-Auth File Sink
file sink writes tokens, optionally response-wrapped and/or encrypted, to
a file. This may be a local file or a file mapped via some other process (NFS,
Gluster, CIFS, etc.).
Once the sink writes the file, it is up to the client to control lifecycle; generally it is best for the client to remove the file as soon as it is seen.
It is also best practice to write the file to a ramdisk, ideally an encrypted
ramdisk, and use appropriate filesystem permissions. The file is currently
0640 permissions as default, but can be overridden with the optional