Bloblang Language Server

A Language Server Protocol (LSP) implementation for Bloblang, the powerful mapping language used in Redpanda Connect.

Features

• Intelligent Code Completion — Auto-complete Bloblang functions and methods with contextual awareness

  • Function completions triggered after operators like =, (, {, [, |, ;
  • Method completions triggered after . (e.g., this.foo.bar.)
  • Named-argument variants for functions/methods with optional parameters
  • Visual status indicators: [β] beta, [⚗] experimental, [⚠] deprecated

• Rich Hover Documentation — Detailed Markdown documentation on hover

  • Function/method signatures with parameter types
  • Status badges and deprecation warnings
  • Inline examples with input/output tables
  • Links to official Redpanda documentation

• Real-time Diagnostics — Live error detection and validation

  • Parse error reporting with line/character positioning
  • Custom import resolution for import "./maps.blobl" statements
  • Diagnostics published via LSP textDocument/publishDiagnostics

• Snippet Support — Tab-stop placeholders for rapid coding

  • Positional arguments for required parameters
  • Named arguments for optional parameters
  • Smart defaults (e.g., 0 for numbers, [] for arrays)

Installation

Pre-built Binaries

Download the latest release for your platform from the Releases page:

Platform	Architectures
Linux	amd64, arm64
macOS	amd64, arm64
Windows	amd64, arm64

From Source

Requires Go 1.26+ and Task:

git clone https://github.com/teyfix/bloblang-lsp.git
cd bloblang-lsp
task build

The binary will be available at target/language-server-<os>-<arch>.

Editor Configuration

Neovim (nvim-lspconfig)

require'lspconfig'.bloblang.setup{
  cmd = { '/path/to/language-server-linux-amd64' },
  filetypes = { 'bloblang', 'blobl' },
  root_dir = require'lspconfig'.util.root_pattern('.git', 'Taskfile.yml'),
}

Emacs (lsp-mode)

(lsp-register-client
 (make-lsp-client :new-connection (lsp-stdio-connection "/path/to/language-server-linux-amd64")
                  :major-modes '(bloblang-mode)
                  :server-id 'bloblang-lsp))

Sublime Text (LSP)

{
  "clients": {
    "bloblang-lsp": {
      "enabled": true,
      "command": ["/path/to/language-server-linux-amd64"],
      "selector": "source.bloblang"
    }
  }
}

Supported LSP Capabilities

Feature	Method	Status
Text Document Sync	textDocument/didOpen	✅ Full document sync
	textDocument/didChange	✅
	textDocument/didClose	✅
Completion	textDocument/completion	✅ Functions, methods, variables
Hover	textDocument/hover	✅ Function/method docs
Diagnostics	textDocument/publishDiagnostics	✅ Parse errors

Architecture

The server is built on:

• glsp — Go LSP framework
• Redpanda Connect — Bloblang parser and runtime
• Benthos — Core Bloblang environment

Development

# Build for current platform
task build:target OS=linux ARCH=amd64

# Build all platforms
task build

# Run tests
go test ./...

# Release (requires GitHub token)
git tag v1.0.0
git push origin v1.0.0

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

License

MIT

Acknowledgments

• Redpanda Data for the excellent Bloblang language and documentation
• The Language Server Protocol team at Microsoft