Table of contents

• go-tlog
  • Features
  • Installation
  • Quick start
  • Configuration
    • type Opts
    • Main API
  • Log levels
  • Output formats
  • Output destinations
  • Examples
  • Testing
  • License

go-tlog

go-tlog is a lightweight and configurable logging library for Go applications.
It provides structured logging with multiple output destinations, flexible formatting, and fine-grained log-level control.

---

Features

• Simple setup via configuration struct
• Text or JSON output formats
• Multiple output targets: stdout, stderr, files
• Log levels: Trace, Debug, Info, Warn, Error
• Automatic timestamp, source file, and line number
• Stacktrace for errors

---

Installation

go get github.com/tarantool/go-tlog@latest

Then import:

import "github.com/tarantool/go-tlog"

---

Quick start

package main

import "github.com/tarantool/go-tlog"

func main() {
	log, err := tlog.New(tlog.Opts{
		Level:  tlog.LevelInfo,
		Format: tlog.FormatText,
		Path:   "stdout",
	})
	if err != nil {
		panic(err)
	}
	defer log.Close()

	logger := log.Logger().With(tlog.String("component", "demo"))
	logger.Info("service started", "port", 8080)
	logger.Error("failed to connect", "err", "timeout")
}

Output:

2025-11-10T13:30:01+05:00 INFO service started component=demo port=8080
2025-11-10T13:30:01+05:00 ERROR failed to connect err=timeout component=demo stacktrace="..."

---

Configuration

type Opts

type Opts struct {
    Level  Level  // minimal log level
    Format Format // FormatText or FormatJSON
    Path   string // comma-separated outputs: "stdout,/var/log/app.log"
}

Main API

Function	Description
tlog.New(opts)	Create a new logger
Logger()	Return the underlying logger for use
Close()	Flush buffers and close file descriptors

---

Log levels

Level	When to use
Trace	Low-level tracing
Debug	Debugging information
Info	Normal operational messages
Warn	Non-fatal warnings
Error	Errors and exceptions (includes stacktrace)

---

Output formats

Format	Example
FormatText	2025-11-10T13:31:45+05:00 INFO message key=value
FormatJSON	{"time":"...","level":"INFO","msg":"message","key":"value"}

---

Output destinations

You can specify multiple targets separated by commas:

Path: "stdout,/tmp/app.log"

Supported targets:

• stdout
• stderr
• File paths (created automatically if not present)

---

Examples

Included examples:

• ExampleNew_text — basic text logger writing to stdout
• ExampleNew_json — JSON logging
• ExampleNew_multi — logging to multiple destinations (stdout,/tmp/...)

Each example demonstrates different combinations of Path, Format, and Level, including how to log to multiple outputs at the same time.

---

Testing

make test

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License

BSD 2-Clause License — see LICENSE