It's technically weird to return a tsweb.Error with no child err,
but it's a sensible thing to want to do, and we shouldn't panic
if it happens.
Signed-off-by: David Anderson <dave@natulte.net>
Handler is like http.Handler, but returns errors. ErrHandler
converts back to an http.Handler, with added error handling
and logging.
Signed-off-by: David Anderson <dave@natulte.net>
Basically, don't trust the OS-level link monitor to only tell you
interesting things. Sanity check it.
Also, move the interfaces package into the net directory now that we
have it.
This lets us publish sets of vars that are breakdowns along one
dimension in a format that Prometheus and Grafana natively know
how to do useful things with.
Signed-off-by: David Anderson <dave@natulte.net>
