I have been playing with emacs again after using vim and code for a long time. Been enjoying it and the muscle memory is back. But I wanted to move to coding in go there instead of code. The old way was gocode but that has been deprecated and no you use gopls. So, first you will need to run GO111MODULE=on go get -u golang.org/x/tools/gopls@latest.


Assuming you use the package manager to install packages you can paste this in ~/.emacs 

(use-package lsp-mode
  :ensure t
  :commands (lsp lsp-deferred)
  :hook (go-mode . lsp-deferred))

;; Set up before-save hooks to format buffer and add/delete imports.
;; Make sure you don't have other gofmt/goimports hooks enabled.
(defun lsp-go-install-save-hooks ()
  (add-hook 'before-save-hook #'lsp-format-buffer t t)
  (add-hook 'before-save-hook #'lsp-organize-imports t t))
(add-hook 'go-mode-hook #'lsp-go-install-save-hooks)

;; Optional - provides fancier overlays.
(use-package lsp-ui
  :ensure t
  :commands lsp-ui-mode)

;; Company mode is a standard completion package that works well with lsp-mode.
(use-package company
  :ensure t
  :config
  ;; Optionally enable completion-as-you-type behavior.
  (setq company-idle-delay 0)
  (setq company-minimum-prefix-length 1))

;; Optional - provides snippet support.
(use-package yasnippet
  :ensure t
  :commands yas-minor-mode
  :hook (go-mode . yas-minor-mode))


If you don’t use the package package management, you probably should and can do so with this in your ~/emacs above the bit above.

(require 'package)
(setq package-enable-at-startup nil)
(add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/"))
(add-to-list 'package-archives '("gnu" . "http://elpa.gnu.org/packages/"))
(add-to-list 'package-archives '("org" . "https://orgmode.org/elpa/") t)
(package-initialize)

(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))

(eval-when-compile
  (require 'use-package))


I got an error when I restarted emacs and it tried to install packages, so you may need to run M-x package-refresh-contents in emacs. Then all was well.

Anyway, load a .go file and autocomplete will be there.