Split contract package

internal/contract/error.go

@@ -0,0 +1,12 @@
+package contract
+
+import "fmt"
+
+type JobNotFoundError struct {
+	State   string
+	Message string
+}
+
+func (e *JobNotFoundError) Error() string {
+	return fmt.Sprintf("%s - %s", e.State, e.Message)
+}