Refactor logger (#1185)

* refactor: logger

* refactor: logging

* refactor: rename func

* refactor: logging

* refactor: logging format

reporter/slack.go

@@ -9,10 +9,10 @@ import (
 
 	"github.com/cenkalti/backoff"
 	"github.com/future-architect/vuls/config"
+	"github.com/future-architect/vuls/logging"
 	"github.com/future-architect/vuls/models"
 	"github.com/nlopes/slack"
 	"github.com/parnurzeal/gorequest"
-	log "github.com/sirupsen/logrus"
 	"golang.org/x/xerrors"
 )
 
@@ -148,14 +148,14 @@ func (w SlackWriter) send(msg message) error {
 				return nil
 			}
 			return xerrors.Errorf(
-				"HTTP POST error. url: %s, resp: %v, body: %s, err: %s",
+				"HTTP POST error. url: %s, resp: %v, body: %s, err: %+v",
 				conf.HookURL, resp, body, errs)
 		}
 		return nil
 	}
 	notify := func(err error, t time.Duration) {
-		log.Warnf("Error %s", err)
-		log.Warn("Retrying in ", t)
+		logging.Log.Warnf("Error %s", err)
+		logging.Log.Warn("Retrying in ", t)
 	}
 	boff := backoff.NewExponentialBackOff()
 	if err := backoff.RetryNotify(f, boff, notify); err != nil {