package log

import (
	"fmt"
	"os"

	"github.com/sirupsen/logrus"
)

// list of common environment variables.
var commonEnvs = []string{"APP_NAME", "APP_VERSION"}

// AddCommonFieldsFromEnv will analyze "common" environment variable and will add those
// as fields on a logrus.Entry.
func AddCommonFieldsFromEnv(l *logrus.Entry) (*logrus.Entry, error) {
	if l == nil {
		return nil, fmt.Errorf("missing logrus entry")
	}

	for _, envKey := range commonEnvs {
		if v := os.Getenv(envKey); v != "" {
			l = logrus.WithField(envKey, v)
		}
	}

	return l, nil
}