Helm Upgraded LSP

An enhanced Helm Language Server Protocol (LSP) built on top of the official helm-ls architecture, adding Kubernetes-aware intelligence, advanced hover features, code actions, and live chart preview.

✨ Features

Unique (not in original helm-ls)

Feature	Description
K8s Schema Hover	Hover over any K8s YAML field (spec, containers, replicas) to see official Kubernetes API documentation
K8s JSON Schema Validation	Validates rendered templates against K8s schemas (fetched & cached from GitHub)
Variable Hover	Hover over $host in range loops → shows map keys; hover over $ing → shows nested values
Keyword Hover	Hover over if / range / with / end / not / and / or → syntax reference
Template-aware YAML Formatting	Formats YAML while preserving {{ }} template blocks (BETA - see below)
Template apiVersion Resolution	Automatically resolves {{ include "helpers.capabilities..." }} to the correct apiVersion using kind inference
Code Actions (AST)	Tree-sitter AST-based code actions: Extract to values.yaml, wrap with | quote, indent → nindent
Helm Render Preview	Renders the current template (or full chart) and opens result in a split buffer
Multi-Values Support	Coalesces values.yaml + all values*.yaml files when rendering and linting
Real-time Helm Lint	Virtual in-memory render on every keystroke — shows Helm template errors as diagnostics

Code Actions

Intelligent code actions triggered on the current cursor position:

Action	Trigger	Description
Extract to Values	On a key: literal-value YAML line	Moves the value to values.yaml and replaces it with a {{ .Values.key }} reference
Add | quote	On a {{ .Values.xxx }} expression	Wraps the expression with | quote for YAML string safety
indent → nindent	On a | indent N pipeline	Converts to | nindent N (adds leading newline)
toYaml + nindent	On a | toYaml pipeline	Appends | nindent N to the pipeline

Helm Render Preview

Two LSP commands available via workspace/executeCommand:

Command	Description
helm.renderPreview	Renders only the current file and shows YAML in a split buffer
helm.renderFullPreview	Renders the entire chart and shows all manifests in a split buffer

If the chart fails to render (e.g. missing values, template syntax error), the error text is shown in the split buffer instead of YAML — making it easy to diagnose what went wrong without leaving Neovim.

Example Neovim keybindings:

vim.keymap.set('n', '<leader>hr', function()
  local uri = vim.uri_from_bufnr(0)
  vim.lsp.buf.execute_command({ command = 'helm.renderPreview', arguments = { uri } })
end, { desc = 'Helm Render Preview' })

vim.keymap.set('n', '<leader>hR', function()
  local uri = vim.uri_from_bufnr(0)
  vim.lsp.buf.execute_command({ command = 'helm.renderFullPreview', arguments = { uri } })
end, { desc = 'Helm Render Full Chart Preview' })

Experimental YAML Formatter (Beta)

The original helm-ls explicitly disabled YAML formatting for templates because standard tools break nindent/indent usage. We have implemented an experimental heuristic formatter that intelligently adjusts YAML block indentations without breaking your {{ }} Go templates.

Disabled by default. To enable it:

require('lspconfig').helm_ls.setup {
  settings = {
    ['helm-ls'] = {
      yamlFormatter = {
        enabled = true
      }
    }
  }
}

Inherited from helm-ls

• .Values. autocompletion & hover with values from values.yaml
• .Chart. / .Release. built-in object hover
• Go-to-definition for .Values references
• include / define template navigation & hover
• Variable definitions & references
• Symbol outline
• yamlls proxy for YAML validation
• Tree-sitter based AST parsing
• Helm lint diagnostics
• Sprig function documentation

Installation

Build from source

git clone https://github.com/acidsugarx/helm-upgraded-lsp.git
cd helm-upgraded-lsp
go build -o helm-lsp ./cmd/helm-lsp

Neovim Setup

-- Detect helm filetype
vim.api.nvim_create_autocmd({ 'BufRead', 'BufNewFile' }, {
  pattern = { '*/templates/*.yaml', '*/templates/*.tpl', '*/templates/**/*.yaml' },
  callback = function() vim.bo.filetype = 'helm' end,
})

-- Register LSP
local lspconfig = require('lspconfig')
local configs = require('lspconfig.configs')

configs.helm_upgraded = {
  default_config = {
    cmd = { '/path/to/helm-lsp', 'serve' },
    filetypes = { 'helm' },
    root_dir = lspconfig.util.root_pattern('Chart.yaml'),
  },
}
lspconfig.helm_upgraded.setup({})

K8s Schema Support

Schemas are automatically fetched from yannh/kubernetes-json-schema and cached locally in /tmp/helm-lsp-schemas/.

Custom Resource Definitions (CRDs)

1. Auto-parsing from chart: Place CRD YAML files in the crds/ directory. The LSP will discover them and generate a local JSON schema.
2. Global Custom Schemas: Place custom JSON schema files in ~/.config/helm-lsp/schemas/. These take priority over downloaded schemas.

Configuration

The LSP uses the same configuration format as helm-ls. See the helm-ls documentation for details.

Acknowledgements

Built on top of helm-ls by Alireza Josheghani (mrjosh) and contributors. Original code distributed under the MIT License (see LICENSE).

License

MIT