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https://github.com/tokio-rs/tracing.git
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7bc97b1abe
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.
41 lines
896 B
Rust
41 lines
896 B
Rust
#[macro_use]
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extern crate tracing;
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#[macro_use]
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extern crate tracing_proc_macros;
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extern crate env_logger;
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extern crate tracing_fmt;
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#[trace]
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fn nth_fibonacci(n: u64) -> u64 {
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if n == 0 || n == 1 {
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debug!("Base case");
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1
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} else {
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debug!("Recursing");
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nth_fibonacci(n - 1) + nth_fibonacci(n - 2)
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}
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}
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#[trace]
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fn fibonacci_seq(to: u64) -> Vec<u64> {
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let mut sequence = vec![];
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for n in 0..=to {
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debug!("Pushing {n} fibonacci", n = n);
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sequence.push(nth_fibonacci(n));
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}
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sequence
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}
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fn main() {
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env_logger::Builder::new().parse("trace").init();
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let subscriber = tracing_fmt::FmtSubscriber::builder().finish();
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tracing::subscriber::with_default(subscriber, || {
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let n: u64 = 5;
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let sequence = fibonacci_seq(n);
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info!("The first {} fibonacci numbers are {:?}", n, sequence);
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})
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}
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