Minimal nvim lsp go configuration

init.vim

call plug#begin()
Plug 'neovim/nvim-lspconfig'
call plug#end()

lua require("lsp_config")

autocmd BufWritePre *.go lua vim.lsp.buf.formatting()
autocmd BufWritePre *.go lua goimports(1000)

lsp_config.lua

local nvim_lsp = require('lspconfig')

local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true

local on_attach = function(client, bufnr)
  local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
  local function buf_set_option(...) vim.api.nvim_buf_set_option(bufnr, ...) end

  buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc')

  -- Mappings.
  local opts = { noremap=true, silent=true }
  buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.declaration()<CR>', opts)
  buf_set_keymap('n', 'gd', '<Cmd>lua vim.lsp.buf.definition()<CR>', opts)
  buf_set_keymap('n', 'ga', '<Cmd>lua vim.lsp.buf.code_action()<CR>', opts)
  buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
  buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
  buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
  buf_set_keymap('n', '<space>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
  buf_set_keymap('n', '<space>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
  buf_set_keymap('n', '<space>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
  buf_set_keymap('n', '<space>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
  buf_set_keymap('n', '<space>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)
  buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
  buf_set_keymap('n', '<space>e', '<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>', opts)
  buf_set_keymap('n', '[d', '<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts)
  buf_set_keymap('n', ']d', '<cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts)
  buf_set_keymap('n', '<space>q', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)

  -- Set some keybinds conditional on server capabilities
  if client.resolved_capabilities.document_formatting then
    buf_set_keymap("n", "ff", "<cmd>lua vim.lsp.buf.formatting()<CR>", opts)
  elseif client.resolved_capabilities.document_range_formatting then
    buf_set_keymap("n", "ff", "<cmd>lua vim.lsp.buf.range_formatting()<CR>", opts)
  end

  -- Set autocommands conditional on server_capabilities
  if client.resolved_capabilities.document_highlight then
    vim.api.nvim_exec([[
      hi LspReferenceRead cterm=bold ctermbg=DarkMagenta guibg=LightYellow
      hi LspReferenceText cterm=bold ctermbg=DarkMagenta guibg=LightYellow
      hi LspReferenceWrite cterm=bold ctermbg=DarkMagenta guibg=LightYellow
      augroup lsp_document_highlight
        autocmd! * <buffer>
        autocmd CursorHold <buffer> lua vim.lsp.buf.document_highlight()
        autocmd CursorMoved <buffer> lua vim.lsp.buf.clear_references()
      augroup END
    ]], false)
  end
end

nvim_lsp.gopls.setup{
	cmd = {'gopls'},
	-- for postfix snippets and analyzers
	capabilities = capabilities,
	    settings = {
	      gopls = {
		      experimentalPostfixCompletions = true,
		      analyses = {
		        unusedparams = true,
		        shadow = true,
		     },
		     staticcheck = true,
		    },
	    },
	on_attach = on_attach,
}

  function goimports(timeoutms)
    local context = { source = { organizeImports = true } }
    vim.validate { context = { context, "t", true } }

    local params = vim.lsp.util.make_range_params()
    params.context = context

    -- See the implementation of the textDocument/codeAction callback
    -- (lua/vim/lsp/handler.lua) for how to do this properly.
    local result = vim.lsp.buf_request_sync(0, "textDocument/codeAction", params, timeout_ms)
    if not result or next(result) == nil then return end
    local actions = result[1].result
    if not actions then return end
    local action = actions[1]

    -- textDocument/codeAction can return either Command[] or CodeAction[]. If it
    -- is a CodeAction, it can have either an edit, a command or both. Edits
    -- should be executed first.
    if action.edit or type(action.command) == "table" then
      if action.edit then
        vim.lsp.util.apply_workspace_edit(action.edit)
      end
      if type(action.command) == "table" then
        vim.lsp.buf.execute_command(action.command)
      end
    else
      vim.lsp.buf.execute_command(action)
    end
  end

--vim.lsp.set_log_level("debug")

~/.config/nvim/

nvim
├── init.vim
└── lua
    └── lsp_config.lua