Feature Request: Evaluation Notifications

[gilligan]

in short:
As a lorri user I would like to be able to be notified whenever an evaluation has finished and know whether it was successful or not.

current scenario:
I am working on a Haskell project and add a dependency to my cabal file. In order to know if this was successful and when I can start using it I have to open my my (otherwise hidden because mostly uninteresting) tmux pane with the lorri process.

desired scenario
I am working on a Haskell project and add a dependency to my cabal file. Everything is built and re-evaluated successfully and lorri triggers a notification which I can see through my dbus notification app.

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Some additional thoughts

• I understand lorri will eventually be running as a daemon in the background. In this case support for a notification like this might be even more desirable.
• I think Generalize watch to support running a command, arbitrary nix files #64 is related to this and it would in fact be possible to use this generic mechanism to trigger notifications using something like notify-end yet I believe that being informed about the state of the evaluation is important enough to be a feature in its own right.
• Instead of only notifying about successful or unsuccessful evaluation completion it might also be useful to include evaluation start. Ideally this would be configurable on the command line.
• https://github.com/hoodie/notify-rust

Looking forward to hear your thoughts on this. Thanks

[Profpatsch]

We could add a --notify flag to the tool that watches for changes.

Would you expect to be notified about every evaluation on every project the daemon watches, or just for some subset of projects?

[gilligan]

@Profpatsch Oh that's a good question. I think I would say every project because everything else would probably be inconvenient and unexpected. Plus evaluations should only occur if I actually do change something in the project and then i would also want to be informed about it.

[domenkozar]

It seems this feature has some intersection with #78 to emit evaluation events