feat: add 'automatic' option to ensure_installed setting

README.md

@@ -114,7 +114,7 @@ Example:
 
 ```lua
 require("nvim-lsp-installer").setup({
-    ensure_installed = { "sumneko_lua", "rust_analyzer" },
+    ensure_installed = "automatic", -- this can alternatively be a list of servers like { "sumneko_lua", "rust_analyzer" }
     ui = {
         icons = {
             server_installed = "✓",
@@ -267,7 +267,8 @@ Illustrations in the logo are derived from [@Kaligule](https://schauderbasis.de/
 
 ```lua
 local DEFAULT_SETTINGS = {
-    -- A list of servers to automatically install. Example: { "rust_analyzer", "sumneko_lua" }
+    -- A list of servers to automatically install, or "automatic". Example: { "rust_analyzer", "sumneko_lua" }
+    -- Setting this to "automatic" will automatically install LSP servers that are set up via lspconfig.
     ensure_installed = {},
     ui = {
         icons = {

doc/nvim-lsp-installer.txt

@@ -158,6 +158,7 @@ Refer to the |nvim-lsp-installer-default-settings| for all available settings.
 Example: >
 
     require("nvim-lsp-installer").setup({
+        ensure_installed = "automatic",
         ui = {
             icons = {
                 server_installed = "✓",
@@ -172,7 +173,8 @@ Example: >
 The following settings are applied by default. >
 
     local DEFAULT_SETTINGS = {
-        -- A list of servers to automatically install. Example: { "rust_analyzer", "sumneko_lua" }
+        -- A list of servers to automatically install, or "automatic". Example: { "rust_analyzer", "sumneko_lua" }
+        -- Setting this to "automatic" will automatically install LSP servers that are set up via lspconfig.
         ensure_installed = {},
         ui = {
             icons = {

lua/nvim-lsp-installer.lua

@@ -37,9 +37,12 @@ function M.setup(config)
     end
     settings.uses_new_setup = true
     require("nvim-lsp-installer.middleware").register_lspconfig_hook()
-    vim.schedule(function()
-        ensure_installed(settings.current.ensure_installed)
-    end)
+
+    if vim.tbl_islist(settings.current.ensure_installed) then
+        vim.schedule(function()
+            ensure_installed(settings.current.ensure_installed)
+        end)
+    end
 end
 
 M.info_window = {

lua/nvim-lsp-installer/middleware.lua

@@ -1,5 +1,6 @@
 local util = require "lspconfig.util"
 local servers = require "nvim-lsp-installer.servers"
+local settings = require "nvim-lsp-installer.settings"
 
 local M = {}
 
@@ -25,6 +26,9 @@ function M.register_lspconfig_hook()
         local ok, server = servers.get_server(config.name)
         if ok then
             merge_in_place(config, server._default_options)
+            if settings.current.ensure_installed == "on_demand" and not server:is_installed() then
+                server:install()
+            end
         end
     end)
 end