logger.nvim

July 18, 2026 · View on GitHub

logger.nvim is a simple runtime logger plugin for Neovim. It provides four log levels, in-memory runtime log storage, optional file logging, and per-plugin derived loggers.

✨ Features
📦 Installation
🔧 Configuration
⚙️ Basic Usage
🔌 Derived Logger
📝 File Logging
👁️ View Runtime Log
📚 API
📊 Logging Levels
📣 Self-Promotion
📄 License

✨ Features

Four log levels: Debug, Info, Warn, Error
Runtime log stored in memory, viewable in a buffer
Optional file logging with append mode
Per-plugin derived loggers with independent level control
Minimal dependencies — uses only Neovim's built-in Lua

📦 Installation

logger.nvim works with all major Neovim plugin managers.

Using nvim-plug

require('plug').add({
  {
    'wsdjeg/logger.nvim',
    config = function()
      require('logger').setup()
    end,
  },
})

Using lazy.nvim

{
  'wsdjeg/logger.nvim',
  config = function()
    require('logger').setup()
  end,
}

Using packer.nvim

use({
  'wsdjeg/logger.nvim',
  config = function()
    require('logger').setup()
  end,
})

Using luarocks
```
luarocks install logger.nvim
```

🔧 Configuration

require('logger').setup({
  level = 1,  -- 0:debug 1:info 2:warn 3:error (default: 1)
  file = '',  -- log file path, empty = runtime only (default: '')
})

⚙️ Basic Usage

local logger = require('logger')

logger.info('plugin initialized')
logger.warn('deprecated API called')
logger.error('failed to load config')
logger.debug('internal state: ' .. tostring(state))

Output format:

[ 22:30:45:123 ] [  Info ] [ logger ] plugin initialized
[ 22:30:45:124 ] [  Warn ] [ logger ] deprecated API called
[ 22:30:45:125 ] [ Error ] [ logger ] failed to load config
[ 22:30:45:126 ] [ Debug ] [ logger ] internal state: nil

🔌 Derived Logger

Create a named logger for your plugin with derive():

local logger = require('logger').derive('myplugin')

logger.info('starting up')
logger.set_level(0)  -- debug level for this plugin only

The derived logger name is right-aligned to 12 characters:

[ 22:30:45:123 ] [  Info ] [    myplugin ] starting up

Each derived logger has its own set_level, independent of the global level.

📝 File Logging

When file is set in setup(), every log message is appended to the file:

require('logger').setup({
  level = 1,
  file = vim.fn.stdpath('cache') .. '/myplugin.log',
})

require('logger').info('this will be written to the file')

Each line in the file has the same format as the runtime log. Messages are appended on each write, so the file persists across sessions.

👁️ View Runtime Log

All log messages are stored in memory. View them at any time:

require('logger').viewRuntimeLog()

Opens a new tab showing all accumulated logs. Press q to close.

To clear the runtime log:

require('logger').clearRuntimeLog()

📚 API

function	description
`setup(opts)`	Initialize with `level` and `file` options
`info(msg)`	Log info-level message
`warn(msg)`	Log warning-level message
`error(msg)`	Log error-level message
`debug(msg)`	Log debug-level message
`derive(name)`	Create plugin-specific logger
`viewRuntimeLog()`	View runtime log in a new tab
`clearRuntimeLog()`	Clear in-memory runtime log

setup(opts)

Initialize the logger with custom configuration.

option	type	default	description
`level`	`0\|1\|2\|3`	`1`	Logging level
`file`	`string`	`''`	Log file path, empty for runtime only

require('logger').setup({
  level = 1,
  file = vim.fn.stdpath('cache') .. '/myapp.log',
})

info(msg)

Log info-level message (visible when level ≤ 1).

logger.info('Plugin initialized successfully')

warn(msg)

Log warning-level message (visible when level ≤ 2).

logger.warn('Deprecated function called')

error(msg)

Log error-level message. Always logged regardless of level.

logger.error('Failed to load configuration')

debug(msg)

Log debug-level message (visible when level = 0).

logger.debug('Variable value: ' .. tostring(value))

derive(name)

Create a named logger instance for your plugin.

Returns a table with info, warn, error, debug, and set_level methods.

local myLogger = require('logger').derive('treesitter')
myLogger.set_level(0)  -- debug level for this logger only
myLogger.debug('Parsing AST')

viewRuntimeLog()

Display the runtime log in a new tab. Press q to close the buffer.

require('logger').viewRuntimeLog()

clearRuntimeLog()

Clear all entries from the in-memory runtime log.

require('logger').clearRuntimeLog()

📊 Logging Levels

Level	Value	Logs
Debug	0	debug, info, warn, error
Info	1	info, warn, error
Warn	2	warn, error
Error	3	error

error messages are always logged regardless of the level setting.

📣 Self-Promotion

Like this plugin? Star the repository on GitHub.

Love this plugin? Follow me on GitHub.

📄 License

This project is licensed under the GPL-3.0 License.