gocommon/log/log.go

package log

import (
	"io"
	"os"

	"github.com/juju/errors"
	"github.com/sirupsen/logrus"

	"git.dev.m-and-m.ovh/mderasse/gocommon/log/hooks/file"
	"git.dev.m-and-m.ovh/mderasse/gocommon/log/hooks/gelf"
)

// InitLog will try to initialize logger by trying to retrieve config from multiple source.
func InitLog() (*logrus.Logger, error) {

	// loading configuration
	c, err := loadConfig()
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

// InitLogFromCustomVaultSecret will initialize logger with a vault secret.
func InitLogFromCustomVaultSecret(secret string) (*logrus.Logger, error) {

	c, err := loadConfigFromVault(secret)
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

// InitLogFromCustomFile will initialize logger with a config file.
func InitLogFromCustomFile(path string) (*logrus.Logger, error) {

	c, err := loadConfigFromFile(path)
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

func initFromSource(c *ConfigStruct) (*logrus.Logger, error) {
	err := c.applyEnv()
	if err != nil {
		return nil, errors.Trace(err)
	}

	c.applyDefault()

	return InitLogFromCustomConfig(c)
}

// InitLogFromCustomConfig will initialize logger from a gaven config.
func InitLogFromCustomConfig(c *ConfigStruct) (*logrus.Logger, error) {

	err := c.IsValid()
	if err != nil {
		return nil, errors.Trace(err)
	}

	level, err := logrus.ParseLevel(*c.Level)
	if err != nil {
		return nil, err
	}

	// init logger
	log := logrus.New()
	log.SetLevel(level)

	if *c.EnableStdOut {
		log.SetOutput(os.Stdout)
	} else {
		log.SetOutput(io.Discard)
	}

	switch *c.Provider {
	case ProviderName_FILE:
		hook, err := file.NewHook(c.FileConfig)
		if err != nil {
			return nil, errors.Trace(err)
		}
		log.AddHook(hook)
	case ProviderName_GELF:
		hook, err := gelf.NewHook(c.GelfConfig)
		if err != nil {
			return nil, errors.Trace(err)
		}
		log.AddHook(hook)
	case ProviderName_NONE:
		fallthrough
	default:
		return nil, errors.BadRequestf("Provider is not handled.")
	}

	return log, nil
}