unalogger

Opinionated logxi based logging with the option of passing errors on to Sentry

Getting started

Install

To install logger pull it with go get like this

go get github.com/unacast/logger

or if you use dep just do a

dep ensure -add github.com/unacast/logger

oooor if you use glide just do a

glide get github.com/unacast/logger
glide install

Usage expamles

Regular stdout logging

package main
import (
    "github.com/unacast/logger"
    "errors"
)

var log = logger.New("main")

func main() {

    // Info takes a message and a var args list of key-value pairs that are 
    log.Info(
        "Log message",
        "jobID", "1312313", "count", 1000,
    )
    
    // Error takes an error as the second argument and it's added to 
    // the list of key-value pairs with "error" as the key 
    err := errors.New("This is an error!")
    log.Info(
        "Error log message",
        err,
        "jobID", "1312313", "count", 1000,
    )
}

Logging to custom logfile, e.g. for apps running on Appengine flex

It might be a good idea to create a local logger package to do the setup with the desired filename etc.

package logger
import (
    "github.com/unacast/logger"
)

const logFileEnv = "UC_[APP NAME HERE]_LOG_FILE"

var (
	logFileName = os.Getenv(logFileEnv)
)

func New(name string) unalogger.UnaLogger {
	return unalogger.NewLogger(
        unalogger.Config{
            Name: name, 
            FileName: logFileName
        }
     )
}

Use the Stackdriver Error Reporting functionality

unalogger has an integration to optionally handle panics and report them as errors to Stackdriver Error Reporting. Initialise the errorClient in the start of your program, typically in main.go.

func main() {

	consts := constants.Consts

	// Enable Stackdriver Errorreporting
	errorClient, recoverPanics := logger.SetUpErrorReporting(context.Background(), consts.Project, "shipit", consts.GitSha)
    // Defering this function handles panics in this scope/goroutine
	defer recoverPanics()
    // Strictly not necessary, 
	defer errorClient.Close()
    ...
}

If you have several sub-goroutines in your app, you have to pass the recoverPanics into them and defer recoverPanics locally to handle panics there.

Loggers

Logxi defaults to using a json formatter in production and a typical log line looks like this

{"_t":"2017-08-25T15:04:44+0200", "_p":"20698", "severity":"INFO", "_n":"main", "message":"The service has successfully launched"}

Some of the keys has been renamed to confrom with the Google Cloud Logging format

Locally logxi uses a formatter that outputs lines like this

15:07:59.502228 INFO goa mount ctrl: K8sStatuses action: Liveness
   route: GET /liveness

Maintainers

• @torbjornvatn