get Swag for Go first
go get -u github.com/swaggo/swag/cmd/swag
Run the Swag at your Go project root path(for instance ~/root/go-peoject-name), Swag will parse comments and generate required files(docs folder and docs/doc.go) at ~/root/go-peoject-name/docs.
swag init
Run swag fmt to format all swagger documents