feat(smalltrip): new exceptions package for structurerd error codes

smalltrip/exceptions/exceptions.go

@@ -0,0 +1,42 @@
+package exceptions
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+type Exception struct {
+	Status   int      `json:"status"`          // HTTP Status Code
+	Code     string   `json:"code"`            // Application error code
+	Message  string   `json:"message"`         // User friendly message
+	Err      error    `json:"error,omitempty"` // Go error
+	Severity Severity `json:"severity"`        // Exception level
+}
+
+var (
+	_ fmt.Stringer = Exception{}
+	_ error        = Exception{}
+	_ http.Handler = Exception{}
+)
+
+func (e Exception) String() string {
+	return fmt.Sprintf("%s %3d %s Exception %q", e.Severity, e.Status, e.Code, e.Message)
+}
+
+func (e Exception) Error() string {
+	return e.String()
+}
+
+func (e Exception) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if e.handler != nil {
+		e.handler(e, w, r)
+	}
+
+	handler, ok := r.Context().Value(handlerFuncCtxKey).(HandlerFunc)
+	if !ok {
+		e.handler(e, w, r)
+	}
+
+	handler(e, w, r)
+}