Replacing format strings with magic

config.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -68,7 +67,7 @@ func loadAndwatchCfgFile(filename string) {
 	provider := file.Provider(filename)
 
 	if cfgError := k.Load(provider, toml.Parser()); cfgError != nil {
-		log.Warn().Msg(fmt.Sprintf("Error while trying to read %s: %s\n", filename, cfgError.Error()))
+		log.Warn().Str("filename", filename).Err(cfgError).Msg("Error while trying to read config file")
 	}
 
 	// Watch for changes and reload when detected
@@ -78,7 +77,7 @@ func loadAndwatchCfgFile(filename string) {
 		}
 
 		if cfgError := k.Load(provider, toml.Parser()); cfgError != nil {
-			log.Warn().Msg(fmt.Sprintf("Error while trying to read %s: %s\n", filename, cfgError.Error()))
+			log.Warn().Str("filename", filename).Err(cfgError).Msg("Error while trying to read config file")
 		}
 	})
 }