Simple hack for calling goimports on buffer on Emacs.

goimports.el

(defun goimports-buffer ()
  "Format current buffer with goimports."
  (interactive)
  (let ((gofmt-command-bak gofmt-command)
        (gofmt-args-bak gofmt-args))
    (setq gofmt-command "goimports"
          gofmt-args nil)
    (with-current-buffer (current-buffer)
      (gofmt))
    (setq gofmt-command gofmt-command-bak
          gofmt-args gofmt-args-bak)))