Setting up a logger is something that pretty much every entrypoint needs
to do, be it a test, a shared library embedded in another app or a
standalone application. Thus, it makes sense to introduce a dedicated
crate that allows us to bundle all the things together, how we want to
do logging.
This allows us to introduce convenience functions like
`firezone_logging::test` which allow you to construct a logger for a
test as a one-liner.
Crucially though, introducing `firezone-logging` gives us a place to
store a default log directive that silences very noisy crates. When
looking into a problem, it is common to start by simply setting the
log-filter to `debug`. Without further action, this floods the output
with logs from crates like `netlink_proto` on Linux. It is very unlikely
that those are the logs that you want to see. Without a preset filter,
the only alternative here is to explicitly turn off the log filter for
`netlink_proto` by typing something like
`RUST_LOG=netlink_proto=off,debug`. Especially when debugging issues
with customers, this is annoying.
Log filters can be overridden, i.e. a 2nd filter that matches the exact
same scope overrides a previous one. Thus, with this design it is still
possible to activate certain logs at runtime, even if they have silenced
by default.
I'd expect `firezone-logging` to attract more functionality in the
future. For example, we want to support re-loading of log-filters on
other platforms. Additionally, where logs get stored could also be
defined in this crate.
---------
Signed-off-by: Thomas Eizinger <thomas@eizinger.io>
Co-authored-by: Reactor Scram <ReactorScram@users.noreply.github.com>
