Logfile support

[simonsan]

There is a TODO comment in trace::component about logfile support:

abscissa/core/src/trace/component.rs

Line 3 in 8ae26ec

// TODO(tarcieri): logfile support?

How would one approach this to add that to abscissa_core?

[jh-devv]

+1

[tony-iqlusion]

Our usages of Abscissa are all with journald, so we won't be adding this ourselves. However, PRs accepted.

[simonsan]

@tony-iqlusion Our usages of Abscissa are all with journald, so we won't be adding this ourselves. However, PRs accepted.

How would you imagine it, something like this?

• another field on the trace::Config struct, holding the logfile path (I guess it would be cleaner to have something like pub trait LogPath and use the associated type in Application for it (https://docs.rs/abscissa/latest/abscissa/prelude/trait.Application.html#associatedtype.Paths), but I think this would need too much modification and would need Provide Path trait for application granting access to common user directories #861 first
• instantiating Config via new and calling with_logfile(&self, path: impl AsRef<Path>) -> Self
• building Tracing component with that

Do we pull tracing-appender as a dependency for this, then?