logger

Simple structured logger for Go

A simple logger package that provides levels, a number of output formats, and named sub-logs. Output formats include plain text, key/value, JSON and AMQP/RabbitMQ

Installation

Install using go get github.com/felix/logger.

Documentation is available at http://godoc.org/github.com/felix/logger

Usage

Create a normal logger

log := logger.New(&logger.Options{
	Name:  "app",
	Level: logger.Debug,
})
log.Error("unable to do anything")

... [INFO ] app: unable to do anything

Create a key/value logger

import "github.com/felix/logger/outputs/keyvalue"

log := logger.New(&logger.Options{
	Name:      "app",
	Level:     logger.Debug,
    Formatter: keyvalue.New(),
})
log.Warn("invalid something", "id", 344, "error", "generally broken")

... [WARN ] app: invalid something id=344 error="generally broken"

... [WARN ] app: invalid something id=344 error="generally broken"

Create a sub-logger

sublog := log.Named("database")
sublog.Info("connection initialised")

... [INFO ] app.database: connection initialised

Create a new Logger with pre-defined values

For major sub-systems there is no need to repeat values for each log call:

reqID := "555"
msgLog := sublog.WithFields("request", reqID)
msgLog.Error("failed to process message")

... [INFO ] app.database: failed to process message request=555

Credits

Solidly based on all the other loggers around, particularly Hashicorp's simple hclog with additions and modifications as required.