Overlog

Golang Logging with Mapped Diagnostic Context

What is it?

This package is Zerolog wrapper with Mapped Diagnostic Context structure like Sl4j.

Installation

go get -u github.com/Trendyol/overlog

Getting Started

over.New() and over.NewDefault() initialize global log field. You can use over.Log() from anywhere after initialize.

Quick start:

package main

import (
    over "github.com/Trendyol/overlog"
)

func main() {
    over.NewDefault()
    over.MDC().Set("x-correlation-id", "1234")
    over.MDC().Set("x-agent-name", "trendyol.com")
    over.SetGlobalFields([]string{"x-correlation-id", "x-agent-name"})

    over.Log().Info("hello world")
}

// Output: {"level":"INFO","time":"2020-05-20 13:02:10,000","source":"overlog/overlogger.go:70","x-agent-name":"trendyol","x-correlation-id":"1234","message":"hello world"}

You can set your own zerolog settings.

package main

import (
    over "github.com/Trendyol/overlog"
    "github.com/rs/zerolog"
    "os"
)

func main() {
    zlogger := zerolog.New(os.Stderr).With().Str("foo", "bar").Logger()
    over.New(zlogger)
    over.MDC().Set("x-correlation-id", "1234")
    over.AddGlobalFields("x-correlation-id")

    over.Log().Info("hello world")
}

// Output: {"level":"info","foo":"bar","x-correlation-id":"1234","message":"hello world"}

Audition middleware example for echo

func main() {
    ...
    over.NewDefault()
    over.SetGlobalFields([]string{"x-agent-name", "x-correlation-id"})
    ...
}

func AuditionPreHandler(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        var agentName = c.Request().Header.Get("x-agent-name")
        if agentName == "" {
            agentName = a.instance.Config().Host
        }
        over.MDC().Set("x-agent-name", agentName)

        var correlationId = c.Request().Header.Get("x-correlation-id")
        if correlationId == "" {
            correlationId = uuid.New().String()
        }
        over.MDC().Set("x-correlation-id", correlationId)

        return next(c)
    }
}

func (a *Application) AuditionAfterCompletion(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        c.Response().After(func() {
            over.MDC().Remove("x-agent-name")
            over.MDC().Remove("x-correlation-id")
        })
        return next(c)
    }
}

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change. Please make sure to update tests as appropriate.

License

MIT