Log errors returned from graphql (#3562)

* Add func methods to logger
* Log errors returned from the graphql interface
* Log authentication
* Log when credentials changed

internal/api/error.go

@@ -0,0 +1,39 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/99designs/gqlgen/graphql"
+	"github.com/stashapp/stash/pkg/logger"
+	"github.com/vektah/gqlparser/v2/gqlerror"
+)
+
+func gqlErrorHandler(ctx context.Context, e error) *gqlerror.Error {
+	// log all errors - for now just log the error message
+	// we can potentially add more context later
+	fc := graphql.GetFieldContext(ctx)
+	if fc != nil {
+		logger.Errorf("%s: %v", fc.Path(), e)
+
+		// log the args in debug level
+		logger.DebugFunc(func() (string, []interface{}) {
+			var args interface{}
+			args = fc.Args
+
+			s, _ := json.Marshal(args)
+			if len(s) > 0 {
+				args = string(s)
+			}
+
+			return "%s: %v", []interface{}{
+				fc.Path(),
+				args,
+			}
+		})
+	}
+
+	// we may also want to transform the error message for the response
+	// for now just return the original error
+	return graphql.DefaultErrorPresenter(ctx, e)
+}