wip refactoring: better logging and error systems

internal/app/api/pkg/middleware/error.go

@@ -0,0 +1,43 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
+)
+
+// Error helps handling errors (if any).
+func Error() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			ctx := context.MustCastFromEchoContext(c)
+			err := next(ctx)
+			if err == nil {
+				// so far so good!
+				return nil
+			}
+			// we log the initial error before returning
+			// the HTTP error.
+			logger := ctx.StandardLogger()
+			logger.Error(err.Error())
+			// handle our custom HTTP error.
+			var httpErr error
+			errCode := standarderror.Code(err)
+			errMessage := standarderror.Message(err)
+			switch errCode {
+			case standarderror.Invalid:
+				httpErr = echo.NewHTTPError(http.StatusBadRequest, errMessage)
+			case standarderror.Timeout:
+				httpErr = echo.NewHTTPError(http.StatusRequestTimeout, errMessage)
+			default:
+				httpErr = echo.NewHTTPError(http.StatusInternalServerError, errMessage)
+			}
+			// required to have a correct status code
+			// in the logs.
+			ctx.Error(httpErr)
+			return httpErr
+		}
+	}
+}