如何在Golang中使用调试日志

Question

I’ve application which should use log in state of debug. i.e. all the logs that I want to provide is like log.debug

I’ve read about it and find the following

https://github.com/Sirupsen/logrus
https://github.com/uber-go/zap

My question is how should I “tell” to the program that now run at debug mode an then all the logs will be printed since this I believe should come from outside … example will be very helpful since Im new to golfing .

Answer 1

Ok, a really simple example of the approach I suggested in the comment:

package main

import (
    "os"

    "github.com/sirupsen/logrus"
)

func init() {
    lvl, ok := os.LookupEnv("LOG_LEVEL")
    // LOG_LEVEL not set, let's default to debug
    if !ok {
        lvl = "debug"
    }
    // parse string, this is built-in feature of logrus
    ll, err := logrus.ParseLevel(lvl)
    if err != nil {
        ll = logrus.DebugLevel
    }
    // set global log level
    logrus.SetLevel(ll)
}

func main() {
    logrus.Debug("Will only be visible if the loglevel permits it")
}

The original comment:

Check codebases that are out there. In go, the common way to do that is to load configuration via environment variables (eg LOG_LEVEL, and use os.Getenv or a config package to load the value). That's why logrus for example allows you to set log levels via ints or strings.

Please, please: before you ask a question, read the basic info about the packages you use. Even the github repo for logrus' main README contains an example setting the log level to a specific level:

https://github.com/sirupsen/logrus#example