Currently there is no good way to get timestamped log entries with the
`tracing-fmt` subscriber. Even with `full`, timestamps are not included.
This is surprising to those coming from other logging crates. It is also
inconvenient to work around, as you would either need to add a custom
field to _all_ spans and events across all your crates, or write your
own subscriber which sort of reduces the usefulness of `fmt`.
This patch introduces a trait for event formatters (`FormatEvent`) so
that it is easier to write more complex formatters (previously they were
just `Fn(...) -> fmt::Result` which would require boxing a closure to
produce). It then implements this new trait for `default::Format`, which
is the new default formatter. It implements "compact"/full formatting
exactly like before, except that is also generic over a timer. The timer
must implement `default::FormatTime`, which has a single method that
writes the current time out to a `fmt::Write`. This method is
implemented for a two new unit structs `SystemTime` and `Uptime`.
`SystemTime` is pretty-printed using `chrono` with the new default
feature `chrono`, and `Debug` of `std::net::SystemTime` is used if the
feature is turned off. `Uptime` prints the fractional number of seconds
since an epoch. Users can also provide `()` as the time formatter to not
produce timestamps in logged entries (accessible through
`default::Format::without_time`).
This patch also switches the default output to the verbose format, with
`compact` offered to return to the compact output format.
Closes#94.
See #95
This branch renames everything from `tokio-trace` to `tracing`.
Unlike PR #98, the nursery crates still depend on the crates.io
versions of `tokio-trace` and `tokio-trace-core`, but renamed
to `tracing`/`tracing-core` in `Cargo.toml`. We can update the
nursery crates to depend on local path dependencies in a
subsequent PR, as that will require making code changes to the
nursery crates.
This branch _also_ updates the minimum Rust version to 1.34.0,
to the shock and horror of the millions of `tracing` users still
on Rust 1.26.0. This was necessary in order to allow renaming
crates in `Cargo.toml`, and to resolve that not using the `dyn`
keyword is now a warning on nightly.
Closes#98Closes#95
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
