Error reporting

[Mastomaki]

It would be good if Toolbox could clearly report errors. Julia and Python tools could have a way to return error messages (maybe also warnings) and they would be shown in a panel with error icon.

[soininen]

Tools are run in separate processes so the only communication channel is Tool's exit status. Currently, Toolbox will mark a non-zero exit status as failure but you need to skim through the consoles to find the actual error message.

There is really no other universal way to communicate possible errors for generic tools.

For Tools that are Toolbox-aware, we could e.g. agree on a standard log file format that the Tool could leave for Toolbox to parse post-execution. This could be for example a JSON file like this:

{
  "warnings": ["using deprecated functionality"]
  "errors": []
}

[soininen]

Forgot about the stderr stream. We could hook on that as well.