Duplicity with S3 needs the AWS credentials as env vars
After having the following error while testing Duplicity with a S3-compatible Object Storage service (Scaleway)
NoAuthHandlerFound: No handler was ready to authenticate. 1 handlers were checked. ['HmacAuthV1Handler'] Check your credentials
I tried passing my credentials through environment variables
export AWS_ACCESS_KEY_ID="aws_access_key_id"
export AWS_SECRET_ACCESS_KEY="aws_secret_access_key"
The error didn't appear in the following test and the backup worked well.