feat(lang): enable terraform-ls language server support in terraform-mode

modules/languages/siren-terraform.el

@@ -8,6 +8,7 @@
 
 (require 'siren-company)
 (require 'siren-reformatter)
+(require 'siren-lsp)
 
 (use-package terraform-mode
   :hook
@@ -18,21 +19,33 @@
 
   :init
   (defun siren-terraform-mode-setup ()
-    (setq tab-width 2)
+    (setq-local tab-width 2)
     (terraform-format-on-save-mode 1))
 
+
   :config
   ;; This does a better job of injecting formatted content than the default
   ;; formatting commands included with terraform-mode.
   (reformatter-define terraform-format
     :program "terraform"
     :args '("fmt" "-no-color" "-")
-    :lighter " TF"))
+    :lighter " TF")
 
-(use-package company-terraform
-  :init
-  (with-eval-after-load 'terraform-mode
-    (company-terraform-init)))
+  ;; When terraform-ls CLI tool is available, setup lsp-mode to use it
+  (when (executable-find "terraform-ls")
+    (with-eval-after-load 'lsp-mode
+      ;; Disable terraform client included with lsp-mode, because it uses
+      ;; terraform-lsp which I have not managed to get working.
+      (add-to-list 'lsp-disabled-clients 'tfls)
+
+      (lsp-register-client
+       (make-lsp-client
+        :new-connection (lsp-stdio-connection '("terraform-ls" "serve"))
+        :major-modes '(terraform-mode)
+        :priority 1
+        :server-id 'terraform-ls))
+
+      (add-hook 'terraform-mode-hook #'lsp-deferred))))
 
 (use-package terraform-doc
   :defer t)