mtlog-lsp

mtlog-lsp

Language Server Protocol implementation for mtlog-analyzer, providing real-time diagnostics and code actions for mtlog usage in Go code.

Overview

mtlog-lsp is a Language Server Protocol (LSP) server that bundles mtlog-analyzer directly, providing zero-subprocess overhead for editor integrations. It implements the JSON-RPC 2.0 protocol and is specifically designed for editors like Zed that require persistent LSP servers.

Installation

go install github.com/willibrandon/mtlog/cmd/mtlog-lsp@latest

Features

• Bundled analyzer - No subprocess spawning, analyzer runs in-process
• Real-time diagnostics - All MTLOG001-MTLOG013 issues detected as you type
• Code actions - Quick fixes for common issues
• Diagnostic suppression - Suppress specific diagnostic codes via workspace configuration
• Performance optimized - 5-minute package cache, concurrent-safe, diagnostic batching
• UTF-16 support - Proper position conversion for LSP compatibility

Usage

With Zed Editor

mtlog-lsp is primarily designed for the Zed extension. Once installed, the extension automatically launches mtlog-lsp when you open Go files.

Standalone

You can also run mtlog-lsp standalone for debugging:

# Start the LSP server (communicates via stdin/stdout)
mtlog-lsp

The server expects LSP messages in JSON-RPC format on stdin and sends responses on stdout.

Configuration

Configuration is passed via LSP initialization options. Example .zed/settings.json:

{
  "lsp": {
    "mtlog-analyzer": {
      "initialization_options": {
        "suppressedCodes": ["MTLOG003", "MTLOG009"],
        "severityOverrides": {
          "MTLOG002": "warning"
        },
        "disableAll": false,
        "commonKeys": ["tenant_id", "org_id"],
        "strictMode": false,
        "ignoreDynamicTemplates": false
      }
    }
  }
}

Configuration Options

• suppressedCodes - Array of diagnostic codes to suppress (e.g., ["MTLOG001", "MTLOG003"])
• severityOverrides - Map of diagnostic codes to severity levels (error, warning, information, hint)
• disableAll - Disable all diagnostics (useful for temporarily turning off)
• commonKeys - Additional context keys to suggest as constants
• strictMode - Enable strict format specifier validation
• ignoreDynamicTemplates - Suppress warnings for non-literal templates

Performance

mtlog-lsp includes several performance optimizations:

• Package caching - 5-minute TTL cache for loaded packages
• Concurrent safety - Mutex-protected cache access
• Diagnostic batching - Limits to 100 diagnostics per file
• Direct integration - No subprocess overhead

Architecture

┌─────────────┐     JSON-RPC 2.0      ┌──────────────┐
│             │◄──────────────────────►│              │
│  Zed Editor │                        │  mtlog-lsp   │
│             │                        │              │
└─────────────┘                        └──────┬───────┘
                                              │
                                              ▼
                                       ┌──────────────┐
                                       │              │
                                       │  Bundled     │
                                       │  Analyzer    │
                                       │              │
                                       └──────────────┘

Diagnostic Codes

mtlog-lsp reports the following diagnostic codes:

• MTLOG001 - Template/argument count mismatch
• MTLOG002 - Property name should be PascalCase
• MTLOG003 - Duplicate property in template
• MTLOG004 - Invalid property name
• MTLOG005 - Complex type needs capturing hint
• MTLOG006 - Invalid format specifier
• MTLOG007 - Error should use Error level
• MTLOG008 - Context key should be constant
• MTLOG009 - With() requires even arguments
• MTLOG010 - With() key must be string
• MTLOG011 - Property override warning
• MTLOG012 - Empty key in With()
• MTLOG013 - Reserved property shadowing

Development

Building

cd cmd/mtlog-lsp
go build

Testing

go test -v ./...

Running with Debug Logging

Debug output goes to stderr while LSP communication uses stdout:

mtlog-lsp 2>debug.log

Troubleshooting

No Diagnostics Appearing

1. Check that mtlog-lsp is running (check process list)
2. Verify the file is recognized as Go (.go extension)
3. Check debug output in stderr for errors

Binary Not Found

Ensure mtlog-lsp is in your PATH or configure the explicit path in your editor settings.

Performance Issues

If analysis is slow:

• The package cache may be expired (5-minute TTL)
• Large packages may take time on first analysis
• Check if you're hitting the 100 diagnostic limit per file

License

MIT License - see LICENSE for details.