adding null_ls to fill the gap of linters that don't have LSPs

.config/nvim/init.lua

@@ -49,6 +49,9 @@ require("user.toggleterm")
 -- Language Server configs and other syntax checking and highlight tools
 require('user.lsp-configs')
 
+-- Language server configs for stuff that doesn't have it
+require('user.null_ls')
+
 -- autocommand to disable lsp semantic highlighting for parameter/variable in 
 -- Dockerfile because it competes with treesitter and is worse
 vim.api.nvim_create_autocmd({"BufEnter", "BufWinEnter"}, {

.config/nvim/lua/user/guard.lua

@@ -0,0 +1,8 @@
+-- https://github.com/nvimdev/guard.nvim
+{
+    cmd = "hadolint",
+    args = "",
+    fname = "Dockerfile",
+    stdin = true, 
+    timeout = "30",          --integer
+}

.config/nvim/lua/user/lazy.lua

@@ -320,6 +320,15 @@ local plugins = {
         cmd = "TSUpdateSync",
         build = "MasonUpdate" -- :MasonUpdate updates registry contents
     },
+    -- this helps bridge the gap between additional linters that don't have proper LSP
+    {
+        'jose-elias-alvarez/null-ls.nvim'
+    },
+    -- may replace null-ls since it is being deprecated
+    --{
+    --    'nvimdev/guard.nvim'
+    --},
+
     -- Diagnostics with leader key + d
     {
         "folke/trouble.nvim",

.config/nvim/lua/user/lsp-configs.lua

@@ -34,7 +34,6 @@ lspconfig.dockerls.setup{
     capabilities = capabilities
 }
 
-
 -- helm
 local configs = require('lspconfig.configs')
 local util = require('lspconfig.util')

.config/nvim/lua/user/null_ls.lua

@@ -0,0 +1,22 @@
+-- TODO: replace null_ls because it's being archived, see:
+-- https://github.com/jose-elias-alvarez/null-ls.nvim/issues/1621
+
+local null_ls = require("null-ls")
+
+null_ls.setup({
+    sources = {
+        -- linting for Dockerfile best practices
+        null_ls.builtins.diagnostics.hadolint,
+        -- markdown linting for actual language
+        null_ls.builtins.diagnostics.vale.with {
+                filetypes = {
+                        'asciidoc',
+                        'markdown',
+                        'tex',
+                        'text',
+                },
+        },
+        -- this should lint github actions
+        null_ls.builtins.diagnostics.actionlint
+    }
+})