Ubuntu indicator to suppress notifications
I built a simple Ubuntu indicator to suppress all desktop notifications when activated - a 'do not disturb' mode if you will. When activated, all desktop notifications using NotifyOSD will be suppressed. As far I can tell, there is no way to disable notifications globally - notwithstanding changing settings (if available) in each individual app. This turned into a minor annoyance whenever someone was at my desk especially since notifications in Ubuntu cannot be dismissed. They are transient and not actionable - I simply have to wait for them to disappear.
A "do not disturb mode" does seem to exist. But it's not clear from the documentation how this mode can be enabled. There is, however, a more hack-ish roundabout way of going about this, which involves renaming the services file and stopping the NotifyOSD process.
This indicator provides a bare-bones UI to do just that. It changes the name of the services file to toggle desktop notifications. Notifications are not queued. They are simply not displayed. The code is open source and on github. It's also very rough at the edges, so proceed with caution! :)
The workaround does require root privileges. Until I figure out how to create a package without errors and warnings, setting this up will require some work. But I do not expect anyone but me to use this at this point.