logger

Simple threadsafe logger interface supporting loglevels with no depencencies.

• Logger logs to a Writable
• StubLogger is for testing, and instead appends messages to an array

Install

# within your go project root
go get github.com/willjp/go-logger

Usage

QuickStart

A default logsetup logs to stderr. You can use the following.

import "github.com/willjp/go-logger"

logger.SetLevel(log.LvDebug)
logger.Error("error msg")
logger.Warn("warn msg")
logger.Info("info msg")
logger.Debug("debug msg")

You can also create your own loggers if you'd like.

import "github.com/willjp/go-logger"

// create logger
logfile = os.Create("foo.log")
defer logfile.Close()
log = logger.New(logfile)

// use logger
log.SetLevel(log.LvDebug)
log.Error("error msg")
log.Warn("warn msg")
log.Info("info msg")
log.Debug("debug msg")

Testable Logs

If you'd like to test logged messages, you may assign the Logger instance to a package variable. In your test, you can then swap the logger with a StubLogger instance. LogMessages are appended to a array fields on the struct - a separate array for each loglevel.

// internal/log/log.go

package log
import (
    "os"
    "github.com/willjp/go-logger"
)

var Log logger.Interface
func init() {
    logRaw := logger.New(os.Stderr)
    Log = &logRaw
}

// main_test.go

package main
import "foo.com/yourpkg/internal/log/log"

func TestMain(t *testing.T) {
    stubLog := logger.NewStubLogger()
    log.Log = &stubLog

    // code you are testing

    if len(stubLog.InfoMsgs) != 1 {
        t.Error("Expected a message to be logged")
    }
    if stubLog.InfoMsgs[0] != "Tadaa, I logged something" {
        t.Error("Expected the log message 'Tadaaa, I logged something'")
    }
}