lsp-cfn.el

lsp-mode integration with cfn-lsp-extra (a Cloudformation language server), heavily inspired by https://www.emacswiki.org/emacs/CfnLint.

Installation

First install cfn-lsp-extra. Then you can install the package from melpa:

(use-package lsp-cfn
  :magic (("\\({\n *\\)? *[\"']AWSTemplateFormatVersion" . lsp-cfn-json-mode)
          ;; SAM templates are also supported
          ("\\({\n *\\)? *[\"']Transform[\"']: [\"']AWS::Serverless-2016-10-31" . lsp-cfn-json-mode)
          ("\\(---\n\\)?AWSTemplateFormatVersion:" . lsp-cfn-yaml-mode)
          ("\\(---\n\\)?Transform: AWS::Serverless-2016-10-31" . lsp-cfn-yaml-mode))
  :hook ((lsp-cfn-yaml-mode . lsp-deferred)
         (lsp-cfn-json-mode . lsp-deferred))
  :config
  (setq completion-ignore-case t))

(setq completion-ignore-case t) is optional, but resource and property names are in CamelCase so you may find completion narrowing better with it.

Usage

The above configuration will trigger lsp whenever a json or yaml is opened with the string AWSTemplateFormatVersion: appearing somwhere in the file.

Alternatively, if you have yasnippet installed, from an empty file type aws and then tab to complete, and that will generate a template skeleton and connect to the LSP server (similarly sam will generate the skeleton of a SAM template).

A list of currently implemented features can be found here.