Improving work with Terraform in Neovim

Working with Terraform on a daily basis and using Neovim as my main and only editor, I recently figured out a few improvements, which I’ll share in this blog post.

Correctly detecting TF filetype

Many users of NeoVim use filetype.nvim, which replaces native filetype detection and speeds up Neovim startup. If you use vim-terraform, which also provides filetype detection, detection from filetype.nvim will be used.

However, it detects *.tf files as files with tf filetype. Due to this, Treesitter does not recognize those files and you’re missing all those juicy highlights.

Compare those two screenshots:

With filetype set as tf:

With filetype set as terraform(I also have p00f/nvim-ts-rainbow installed):

Fortunately, filetype.nvim provides a way to override the filetype detection:

use {
    "nathom/filetype.nvim",
    config = function()
        require("filetype").setup {
            overrides = {
                extensions = {
                    tf = "terraform",
                    tfvars = "terraform",
                    tfstate = "json",
                },
            },
        }
    end,
}

Getting rid of the vim-terraform

vim-terraform provides filetype detection, syntax highlighting, auto-formatting and some other features. As mentioned above, filetype detection is overriden by the filetype.nvim, syntax highlighting is done by Treesitter, and auto-formatting can be done by the null-ls:

local null_ls = require "null-ls"
local b = null_ls.builtins

local sources = {
    b.formatting.terraform_fmt,
    ...
}

If you’ll use both filetype.nvim and vim-terraform, you’ll be formatting terraform files twice on each save.

Adding Tabnine and CoPilot

To speed up writing Terraform files, I’m using TabNine. It works great, but you can go even further and combine it with CoPilot.

With the recently introduced copilot.lua and the completion source copilot-cmp, writing Terraform files is now as easy as writing Go code: