mod.rs source code [crates/tracing_subscriber/src/fmt/format/mod.rs]

1	//! Formatters for logging `tracing` events.
2	//!
3	//! This module provides several formatter implementations, as well as utilities
4	//! for implementing custom formatters.
5	//!
6	//! # Formatters
7	//! This module provides a number of formatter implementations:
8	//!
9	//! * [`Full`]: The default formatter. This emits human-readable,
10	//! single-line logs for each event that occurs, with the current span context
11	//! displayed before the formatted representation of the event. See
12	//! [here](Full#example-output) for sample output.
13	//!
14	//! * [`Compact`]: A variant of the default formatter, optimized for
15	//! short line lengths. Fields from the current span context are appended to
16	//! the fields of the formatted event, and span names are not shown; the
17	//! verbosity level is abbreviated to a single character. See
18	//! [here](Compact#example-output) for sample output.
19	//!
20	//! * [`Pretty`]: Emits excessively pretty, multi-line logs, optimized
21	//! for human readability. This is primarily intended to be used in local
22	//! development and debugging, or for command-line applications, where
23	//! automated analysis and compact storage of logs is less of a priority than
24	//! readability and visual appeal. See [here](Pretty#example-output)
25	//! for sample output.
26	//!
27	//! [`Json`]: Outputs newline-delimited JSON logs. This is intended*
28	//! for production use with systems where structured logs are consumed as JSON
29	//! by analysis and viewing tools. The JSON output is not optimized for human
30	//! readability. See [here](Json#example-output) for sample output.
31	use super::time::{FormatTime, SystemTime};
32	use crate::{
33	field::{MakeOutput, MakeVisitor, RecordFields, VisitFmt, VisitOutput},
34	fmt::fmt_layer::FmtContext,
35	fmt::fmt_layer::FormattedFields,
36	registry::LookupSpan,
37	};
38
39	use std::fmt::{self, Debug, Display, Write};
40	use tracing_core::{
41	field::{self, Field, Visit},
42	span, Event, Level, Subscriber,
43	};
44
45	#[cfg(feature = "tracing-log")]
46	use tracing_log::NormalizeEvent;
47
48	#[cfg(feature = "ansi")]
49	use nu_ansi_term::{Color, Style};
50
51	#[cfg(feature = "json")]
52	mod json;
53	#[cfg(feature = "json")]
54	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
55	pub use json::*;
56
57	#[cfg(feature = "ansi")]
58	mod pretty;
59	#[cfg(feature = "ansi")]
60	#[cfg_attr(docsrs, doc(cfg(feature = "ansi")))]
61	pub use pretty::*;
62
63	/// A type that can format a tracing [`Event`] to a [`Writer`].
64	///
65	/// `FormatEvent` is primarily used in the context of [`fmt::Subscriber`] or
66	/// [`fmt::Layer`]. Each time an event is dispatched to [`fmt::Subscriber`] or
67	/// [`fmt::Layer`], the subscriber or layer
68	/// forwards it to its associated `FormatEvent` to emit a log message.
69	///
70	/// This trait is already implemented for function pointers with the same
71	/// signature as `format_event`.
72	///
73	/// # Arguments
74	///
75	/// The following arguments are passed to `FormatEvent::format_event`:
76	///
77	/// A* [`FmtContext`]. This is an extension of the [`layer::Context`] type,
78	/// which can be used for accessing stored information such as the current
79	/// span context an event occurred in.
80	///
81	/// In addition, [`FmtContext`] exposes access to the [`FormatFields`]
82	/// implementation that the subscriber was configured to use via the
83	/// [`FmtContext::field_format`] method. This can be used when the
84	/// [`FormatEvent`] implementation needs to format the event's fields.
85	///
86	/// For convenience, [`FmtContext`] also [implements `FormatFields`],
87	/// forwarding to the configured [`FormatFields`] type.
88	///
89	/// A* [`Writer`] to which the formatted representation of the event is
90	/// written. This type implements the [`std::fmt::Write`] trait, and therefore
91	/// can be used with the [`std::write!`] and [`std::writeln!`] macros, as well
92	/// as calling [`std::fmt::Write`] methods directly.
93	///
94	/// The [`Writer`] type also implements additional methods that provide
95	/// information about how the event should be formatted. The
96	/// [`Writer::has_ansi_escapes`] method indicates whether [ANSI terminal
97	/// escape codes] are supported by the underlying I/O writer that the event
98	/// will be written to. If this returns `true`, the formatter is permitted to
99	/// use ANSI escape codes to add colors and other text formatting to its
100	/// output. If it returns `false`, the event will be written to an output that
101	/// does not support ANSI escape codes (such as a log file), and they should
102	/// not be emitted.
103	///
104	/// Crates like [`nu_ansi_term`] and [`owo-colors`] can be used to add ANSI
105	/// escape codes to formatted output.
106	///
107	/// The actual* [`Event`] to be formatted.
108	///
109	/// # Examples
110	///
111	/// This example re-implements a simiplified version of this crate's [default
112	/// formatter]:
113	///
114	/// ```rust
115	/// use std::fmt;
116	/// use tracing_core::{Subscriber, Event};
117	/// use tracing_subscriber::fmt::{
118	/// format::{self, FormatEvent, FormatFields},
119	/// FmtContext,
120	/// FormattedFields,
121	/// };
122	/// use tracing_subscriber::registry::LookupSpan;
123	///
124	/// struct MyFormatter;
125	///
126	/// impl<S, N> FormatEvent<S, N> for MyFormatter
127	/// where
128	/// S: Subscriber + for<'a> LookupSpan<'a>,
129	/// N: for<'a> FormatFields<'a> + 'static,
130	/// {
131	/// fn format_event(
132	/// &self,
133	/// ctx: &FmtContext<'_, S, N>,
134	/// mut writer: format::Writer<'_>,
135	/// event: &Event<'_>,
136	/// ) -> fmt::Result {
137	/// // Format values from the event's's metadata:
138	/// let metadata = event.metadata();
139	/// write!(&mut writer, "{} {}: ", metadata.level(), metadata.target())?;
140	///
141	/// // Format all the spans in the event's span context.
142	/// if let Some(scope) = ctx.event_scope() {
143	/// for span in scope.from_root() {
144	/// write!(writer, "{}", span.name())?;
145	///
146	/// // `FormattedFields` is a formatted representation of the span's
147	/// // fields, which is stored in its extensions by the `fmt` layer's
148	/// // `new_span` method. The fields will have been formatted
149	/// // by the same field formatter that's provided to the event
150	/// // formatter in the `FmtContext`.
151	/// let ext = span.extensions();
152	/// let fields = &ext
153	/// .get::<FormattedFields<N>>()
154	/// .expect("will never be `None`");
155	///
156	/// // Skip formatting the fields if the span had no fields.
157	/// if !fields.is_empty() {
158	/// write!(writer, "{{{}}}", fields)?;
159	/// }
160	/// write!(writer, ": ")?;
161	/// }
162	/// }
163	///
164	/// // Write fields on the event
165	/// ctx.field_format().format_fields(writer.by_ref(), event)?;
166	///
167	/// writeln!(writer)
168	/// }
169	/// }
170	///
171	/// let _subscriber = tracing_subscriber::fmt()
172	/// .event_format(MyFormatter)
173	/// .init();
174	///
175	/// let _span = tracing::info_span!("my_span", answer = `42`).entered();
176	/// tracing::info!(question = "life, the universe, and everything", "hello world");
177	/// ```
178	///
179	/// This formatter will print events like this:
180	///
181	/// ```text
182	/// DEBUG yak_shaving::shaver: some-span{field-on-span=foo}: started shaving yak
183	/// ```
184	///
185	/// [`layer::Context`]: crate::layer::Context
186	/// [`fmt::Layer`]: super::Layer
187	/// [`fmt::Subscriber`]: super::Subscriber
188	/// [`Event`]: tracing::Event
189	/// [implements `FormatFields`]: super::FmtContext#impl-FormatFields<'writer>
190	/// [ANSI terminal escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
191	/// [`Writer::has_ansi_escapes`]: Writer::has_ansi_escapes
192	/// [`nu_ansi_term`]: https://crates.io/crates/nu_ansi_term
193	/// [`owo-colors`]: https://crates.io/crates/owo-colors
194	/// [default formatter]: Full
195	pub trait FormatEvent<S, N>
196	where
197	S: Subscriber + for<'a> dynLookupSpan<'a>,
198	N: for<'a> dynFormatFields<'a> + 'static,
199	{
200	/// Write a log message for `Event` in `Context` to the given [`Writer`].
201	fn format_event(
202	&self,
203	ctx: &FmtContext<'_, S, N>,
204	writer: Writer<'_>,
205	event: &Event<'_>,
206	) -> fmt::Result;
207	}
208
209	impl<S, N> FormatEvent<S, N>
210	for fn(ctx: &FmtContext<'_, S, N>, Writer<'_>, &Event<'_>) -> fmt::Result
211	where
212	S: Subscriber + for<'a> dynLookupSpan<'a>,
213	N: for<'a> dynFormatFields<'a> + 'static,
214	{
215	fn format_event(
216	&self,
217	ctx: &FmtContext<'_, S, N>,
218	writer: Writer<'_>,
219	event: &Event<'_>,
220	) -> fmt::Result {
221	(*self)(ctx, writer, event)
222	}
223	}
224	/// A type that can format a [set of fields] to a [`Writer`].
225	///
226	/// `FormatFields` is primarily used in the context of [`FmtSubscriber`]. Each
227	/// time a span or event with fields is recorded, the subscriber will format
228	/// those fields with its associated `FormatFields` implementation.
229	///
230	/// [set of fields]: crate::field::RecordFields
231	/// [`FmtSubscriber`]: super::Subscriber
232	pub trait FormatFields<'writer> {
233	/// Format the provided `fields` to the provided [`Writer`], returning a result.
234	fn format_fields<R: RecordFields>(&self, writer: Writer<'writer>, fields: R) -> fmt::Result;
235
236	/// Record additional field(s) on an existing span.
237	///
238	/// By default, this appends a space to the current set of fields if it is
239	/// non-empty, and then calls `self.format_fields`. If different behavior is
240	/// required, the default implementation of this method can be overridden.
241	fn add_fields(
242	&self,
243	current: &'writer mut FormattedFields<Self>,
244	fields: &span::Record<'_>,
245	) -> fmt::Result {
246	if !current.fields.is_empty() {
247	current.fields.push(ch:' ');
248	}
249	self.format_fields(current.as_writer(), fields)
250	}
251	}
252
253	/// Returns the default configuration for an [event formatter].
254	///
255	/// Methods on the returned event formatter can be used for further
256	/// configuration. For example:
257	///
258	/// ```rust
259	/// let format = tracing_subscriber::fmt::format()
260	/// .without_time() // Don't include timestamps
261	/// .with_target(`false`) // Don't include event targets.
262	/// .with_level(`false`) // Don't include event levels.
263	/// .compact(); // Use a more compact, abbreviated format.
264	///
265	/// // Use the configured formatter when building a new subscriber.
266	/// tracing_subscriber::fmt()
267	/// .event_format(format)
268	/// .init();
269	/// ```
270	pub fn format() -> Format {
271	Format::default()
272	}
273
274	/// Returns the default configuration for a JSON [event formatter].
275	#[cfg(feature = "json")]
276	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
277	pub fn json() -> Format<Json> {
278	format().json()
279	}
280
281	/// Returns a [`FormatFields`] implementation that formats fields using the
282	/// provided function or closure.
283	///
284	pub fn debug_fn<F>(f: F) -> FieldFn<F>
285	where
286	F: Fn(&mut Writer<'_>, &Field, &dyn fmt::Debug) -> fmt::Result + Clone,
287	{
288	FieldFn(f)
289	}
290
291	/// A writer to which formatted representations of spans and events are written.
292	///
293	/// This type is provided as input to the [`FormatEvent::format_event`] and
294	/// [`FormatFields::format_fields`] methods, which will write formatted
295	/// representations of [`Event`]s and [fields] to the `Writer`.
296	///
297	/// This type implements the [`std::fmt::Write`] trait, allowing it to be used
298	/// with any function that takes an instance of [`std::fmt::Write`].
299	/// Additionally, it can be used with the standard library's [`std::write!`] and
300	/// [`std::writeln!`] macros.
301	///
302	/// Additionally, a `Writer` may expose additional `tracing`-specific
303	/// information to the formatter implementation.
304	///
305	/// [fields]: tracing_core::field
306	pub struct Writer<'writer> {
307	writer: &'writer mut dyn fmt::Write,
308	// TODO(eliza): add ANSI support
309	is_ansi: bool,
310	}
311
312	/// A [`FormatFields`] implementation that formats fields by calling a function
313	/// or closure.
314	///
315	#[derive(Debug, Clone)]
316	pub struct FieldFn<F>(F);
317	/// The [visitor] produced by [`FieldFn`]'s [`MakeVisitor`] implementation.
318	///
319	/// [visitor]: super::super::field::Visit
320	/// [`MakeVisitor`]: super::super::field::MakeVisitor
321	pub struct FieldFnVisitor<'a, F> {
322	f: F,
323	writer: Writer<'a>,
324	result: fmt::Result,
325	}
326	/// Marker for [`Format`] that indicates that the compact log format should be used.
327	///
328	/// The compact format includes fields from all currently entered spans, after
329	/// the event's fields. Span fields are ordered (but not grouped) by
330	/// span, and span names are not shown. A more compact representation of the
331	/// event's [`Level`] is used, and additional information—such as the event's
332	/// target—is disabled by default.
333	///
334	/// # Example Output
335	///
336	/// <pre><font color="#4E9A06"><b>:;</b></font> <font color="#4E9A06">cargo</font> run --example fmt-compact
337	/// <font color="#4E9A06"><b> Finished</b></font> dev [unoptimized + debuginfo] target(s) in 0.08s
338	/// <font color="#4E9A06"><b> Running</b></font> `target/debug/examples/fmt-compact`
339	/// <font color="#AAAAAA">2022-02-17T19:51:05.809287Z </font><font color="#4E9A06"> INFO</font> <b>fmt_compact</b><font color="#AAAAAA">: preparing to shave yaks </font><i>number_of_yaks</i><font color="#AAAAAA">=3</font>
340	/// <font color="#AAAAAA">2022-02-17T19:51:05.809367Z </font><font color="#4E9A06"> INFO</font> <b>shaving_yaks</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: shaving yaks </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
341	/// <font color="#AAAAAA">2022-02-17T19:51:05.809414Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!" </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=1</font>
342	/// <font color="#AAAAAA">2022-02-17T19:51:05.809443Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: yak shaved successfully </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=1</font>
343	/// <font color="#AAAAAA">2022-02-17T19:51:05.809477Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks</b>: <b>yak_events</b><font color="#AAAAAA">: </font><i>yak</i><font color="#AAAAAA">=1 </font><i>shaved</i><font color="#AAAAAA">=true </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
344	/// <font color="#AAAAAA">2022-02-17T19:51:05.809500Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: </font><i>yaks_shaved</i><font color="#AAAAAA">=1 </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
345	/// <font color="#AAAAAA">2022-02-17T19:51:05.809531Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!" </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=2</font>
346	/// <font color="#AAAAAA">2022-02-17T19:51:05.809554Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: yak shaved successfully </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=2</font>
347	/// <font color="#AAAAAA">2022-02-17T19:51:05.809581Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks</b>: <b>yak_events</b><font color="#AAAAAA">: </font><i>yak</i><font color="#AAAAAA">=2 </font><i>shaved</i><font color="#AAAAAA">=true </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
348	/// <font color="#AAAAAA">2022-02-17T19:51:05.809606Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: </font><i>yaks_shaved</i><font color="#AAAAAA">=2 </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
349	/// <font color="#AAAAAA">2022-02-17T19:51:05.809635Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!" </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=3</font>
350	/// <font color="#AAAAAA">2022-02-17T19:51:05.809664Z </font><font color="#C4A000"> WARN</font> <b>shaving_yaks</b>:<b>shave</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: could not locate yak </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3 </font><font color="#AAAAAA"><i>yak</i></font><font color="#AAAAAA">=3</font>
351	/// <font color="#AAAAAA">2022-02-17T19:51:05.809693Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks</b>: <b>yak_events</b><font color="#AAAAAA">: </font><i>yak</i><font color="#AAAAAA">=3 </font><i>shaved</i><font color="#AAAAAA">=false </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
352	/// <font color="#AAAAAA">2022-02-17T19:51:05.809717Z </font><font color="#CC0000">ERROR</font> <b>shaving_yaks</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: failed to shave yak </font><i>yak</i><font color="#AAAAAA">=3 </font><i>error</i><font color="#AAAAAA">=missing yak </font><i>error.sources</i><font color="#AAAAAA">=[out of space, out of cash] </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
353	/// <font color="#AAAAAA">2022-02-17T19:51:05.809743Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks</b>: <b>fmt_compact::yak_shave</b><font color="#AAAAAA">: </font><i>yaks_shaved</i><font color="#AAAAAA">=2 </font><font color="#AAAAAA"><i>yaks</i></font><font color="#AAAAAA">=3</font>
354	/// <font color="#AAAAAA">2022-02-17T19:51:05.809768Z </font><font color="#4E9A06"> INFO</font> <b>fmt_compact</b><font color="#AAAAAA">: yak shaving completed </font><i>all_yaks_shaved</i><font color="#AAAAAA">=false</font>
355	///
356	/// </pre>
357	#[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
358	pub struct Compact;
359
360	/// Marker for [`Format`] that indicates that the default log format should be used.
361	///
362	/// This formatter shows the span context before printing event data. Spans are
363	/// displayed including their names and fields.
364	///
365	/// # Example Output
366	///
367	/// <pre><font color="#4E9A06"><b>:;</b></font> <font color="#4E9A06">cargo</font> run --example fmt
368	/// <font color="#4E9A06"><b> Finished</b></font> dev [unoptimized + debuginfo] target(s) in 0.08s
369	/// <font color="#4E9A06"><b> Running</b></font> `target/debug/examples/fmt`
370	/// <font color="#AAAAAA">2022-02-15T18:40:14.289898Z </font><font color="#4E9A06"> INFO</font> fmt: preparing to shave yaks <i>number_of_yaks</i><font color="#AAAAAA">=3</font>
371	/// <font color="#AAAAAA">2022-02-15T18:40:14.289974Z </font><font color="#4E9A06"> INFO</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: shaving yaks</font>
372	/// <font color="#AAAAAA">2022-02-15T18:40:14.290011Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=1</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!"</font>
373	/// <font color="#AAAAAA">2022-02-15T18:40:14.290038Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=1</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: yak shaved successfully</font>
374	/// <font color="#AAAAAA">2022-02-15T18:40:14.290070Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: yak_events: </font><i>yak</i><font color="#AAAAAA">=1 </font><i>shaved</i><font color="#AAAAAA">=true</font>
375	/// <font color="#AAAAAA">2022-02-15T18:40:14.290089Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: </font><i>yaks_shaved</i><font color="#AAAAAA">=1</font>
376	/// <font color="#AAAAAA">2022-02-15T18:40:14.290114Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=2</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!"</font>
377	/// <font color="#AAAAAA">2022-02-15T18:40:14.290134Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=2</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: yak shaved successfully</font>
378	/// <font color="#AAAAAA">2022-02-15T18:40:14.290157Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: yak_events: </font><i>yak</i><font color="#AAAAAA">=2 </font><i>shaved</i><font color="#AAAAAA">=true</font>
379	/// <font color="#AAAAAA">2022-02-15T18:40:14.290174Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: </font><i>yaks_shaved</i><font color="#AAAAAA">=2</font>
380	/// <font color="#AAAAAA">2022-02-15T18:40:14.290198Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: hello! I'm gonna shave a yak </font><i>excitement</i><font color="#AAAAAA">="yay!"</font>
381	/// <font color="#AAAAAA">2022-02-15T18:40:14.290222Z </font><font color="#C4A000"> WARN</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">:</font><b>shave{</b><i>yak</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: could not locate yak</font>
382	/// <font color="#AAAAAA">2022-02-15T18:40:14.290247Z </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: yak_events: </font><i>yak</i><font color="#AAAAAA">=3 </font><i>shaved</i><font color="#AAAAAA">=false</font>
383	/// <font color="#AAAAAA">2022-02-15T18:40:14.290268Z </font><font color="#CC0000">ERROR</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: failed to shave yak </font><i>yak</i><font color="#AAAAAA">=3 </font><i>error</i><font color="#AAAAAA">=missing yak </font><i>error.sources</i><font color="#AAAAAA">=[out of space, out of cash]</font>
384	/// <font color="#AAAAAA">2022-02-15T18:40:14.290287Z </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b><i>yaks</i><font color="#AAAAAA">=3</font><b>}</b><font color="#AAAAAA">: fmt::yak_shave: </font><i>yaks_shaved</i><font color="#AAAAAA">=2</font>
385	/// <font color="#AAAAAA">2022-02-15T18:40:14.290309Z </font><font color="#4E9A06"> INFO</font> fmt: yak shaving completed. <i>all_yaks_shaved</i><font color="#AAAAAA">=false</font>
386	/// </pre>
387	#[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
388	pub struct Full;
389
390	/// A pre-configured event formatter.
391	///
392	/// You will usually want to use this as the `FormatEvent` for a `FmtSubscriber`.
393	///
394	/// The default logging format, [`Full`] includes all fields in each event and its containing
395	/// spans. The [`Compact`] logging format is intended to produce shorter log
396	/// lines; it displays each event's fields, along with fields from the current
397	/// span context, but other information is abbreviated. The [`Pretty`] logging
398	/// format is an extra-verbose, multi-line human-readable logging format
399	/// intended for use in development.
400	#[derive(Debug, Clone)]
401	pub struct Format<F = Full, T = SystemTime> {
402	format: F,
403	pub(crate) timer: T,
404	pub(crate) ansi: Option<bool>,
405	pub(crate) display_timestamp: bool,
406	pub(crate) display_target: bool,
407	pub(crate) display_level: bool,
408	pub(crate) display_thread_id: bool,
409	pub(crate) display_thread_name: bool,
410	pub(crate) display_filename: bool,
411	pub(crate) display_line_number: bool,
412	}
413
414	// === impl Writer ===
415
416	impl<'writer> Writer<'writer> {
417	// TODO(eliza): consider making this a public API?
418	// We may not want to do that if we choose to expose specialized
419	// constructors instead (e.g. `from_string` that stores whether the string
420	// is empty...?)
421	//(@kaifastromai) I suppose having dedicated constructors may have certain benefits
422	// but I am not privy to the larger direction of tracing/subscriber.
423	/// Create a new [`Writer`] from any type that implements [`fmt::Write`].
424	///
425	/// The returned `Writer` value may be passed as an argument to methods
426	/// such as [`Format::format_event`]. Since constructing a `Writer`
427	/// mutably borrows the underlying [`fmt::Write`] instance, that value may
428	/// be accessed again once the `Writer` is dropped. For example, if the
429	/// value implementing [`fmt::Write`] is a [`String`], it will contain
430	/// the formatted output of [`Format::format_event`], which may then be
431	/// used for other purposes.
432	#[must_use]
433	pub fn new(writer: &'writer mut impl fmt::Write) -> Self {
434	Self {
435	writer: writer as &mut dyn fmt::Write,
436	is_ansi: `false`,
437	}
438	}
439
440	// TODO(eliza): consider making this a public API?
441	pub(crate) fn with_ansi(self, is_ansi: bool) -> Self {
442	Self { is_ansi, ..self }
443	}
444
445	/// Return a new `Writer` that mutably borrows `self`.
446	///
447	/// This can be used to temporarily borrow a `Writer` to pass a new `Writer`
448	/// to a function that takes a `Writer` by value, allowing the original writer
449	/// to still be used once that function returns.
450	pub fn by_ref(&mut self) -> Writer<'_> {
451	let is_ansi = self.is_ansi;
452	Writer {
453	writer: self as &mut dyn fmt::Write,
454	is_ansi,
455	}
456	}
457
458	/// Writes a string slice into this `Writer`, returning whether the write succeeded.
459	///
460	/// This method can only succeed if the entire string slice was successfully
461	/// written, and this method will not return until all data has been written
462	/// or an error occurs.
463	///
464	/// This is identical to calling the [`write_str` method] from the `Writer`'s
465	/// [`std::fmt::Write`] implementation. However, it is also provided as an
466	/// inherent method, so that `Writer`s can be used without needing to import the
467	/// [`std::fmt::Write`] trait.
468	///
469	/// # Errors
470	///
471	/// This function will return an instance of [`std::fmt::Error`] on error.
472	///
473	/// [`write_str` method]: std::fmt::Write::write_str
474	#[inline]
475	pub fn write_str(&mut self, s: &str) -> fmt::Result {
476	self.writer.write_str(s)
477	}
478
479	/// Writes a [`char`] into this writer, returning whether the write succeeded.
480	///
481	/// A single [`char`] may be encoded as more than one byte.
482	/// This method can only succeed if the entire byte sequence was successfully
483	/// written, and this method will not return until all data has been
484	/// written or an error occurs.
485	///
486	/// This is identical to calling the [`write_char` method] from the `Writer`'s
487	/// [`std::fmt::Write`] implementation. However, it is also provided as an
488	/// inherent method, so that `Writer`s can be used without needing to import the
489	/// [`std::fmt::Write`] trait.
490	///
491	/// # Errors
492	///
493	/// This function will return an instance of [`std::fmt::Error`] on error.
494	///
495	/// [`write_char` method]: std::fmt::Write::write_char
496	#[inline]
497	pub fn write_char(&mut self, c: char) -> fmt::Result {
498	self.writer.write_char(c)
499	}
500
501	/// Glue for usage of the [`write!`] macro with `Writer`s.
502	///
503	/// This method should generally not be invoked manually, but rather through
504	/// the [`write!`] macro itself.
505	///
506	/// This is identical to calling the [`write_fmt` method] from the `Writer`'s
507	/// [`std::fmt::Write`] implementation. However, it is also provided as an
508	/// inherent method, so that `Writer`s can be used with the [`write!` macro]
509	/// without needing to import the
510	/// [`std::fmt::Write`] trait.
511	///
512	/// [`write_fmt` method]: std::fmt::Write::write_fmt
513	pub fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> fmt::Result {
514	self.writer.write_fmt(args)
515	}
516
517	/// Returns `true` if [ANSI escape codes] may be used to add colors
518	/// and other formatting when writing to this `Writer`.
519	///
520	/// If this returns `false`, formatters should not emit ANSI escape codes.
521	///
522	/// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
523	pub fn has_ansi_escapes(&self) -> bool {
524	self.is_ansi
525	}
526
527	pub(in crate::fmt::format) fn bold(&self) -> Style {
528	#[cfg(feature = "ansi")]
529	{
530	if self.is_ansi {
531	return Style::new().bold();
532	}
533	}
534
535	Style::new()
536	}
537
538	pub(in crate::fmt::format) fn dimmed(&self) -> Style {
539	#[cfg(feature = "ansi")]
540	{
541	if self.is_ansi {
542	return Style::new().dimmed();
543	}
544	}
545
546	Style::new()
547	}
548
549	pub(in crate::fmt::format) fn italic(&self) -> Style {
550	#[cfg(feature = "ansi")]
551	{
552	if self.is_ansi {
553	return Style::new().italic();
554	}
555	}
556
557	Style::new()
558	}
559	}
560
561	impl fmt::Write for Writer<'_> {
562	#[inline]
563	fn write_str(&mut self, s: &str) -> fmt::Result {
564	Writer::write_str(self, s)
565	}
566
567	#[inline]
568	fn write_char(&mut self, c: char) -> fmt::Result {
569	Writer::write_char(self, c)
570	}
571
572	#[inline]
573	fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> fmt::Result {
574	Writer::write_fmt(self, args)
575	}
576	}
577
578	impl fmt::Debug for Writer<'_> {
579	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
580	f&mut DebugStruct<'_, '_>.debug_struct("Writer")
581	.field("writer", &format_args!("<&mut dyn fmt::Write>"))
582	.field(name:"is_ansi", &self.is_ansi)
583	.finish()
584	}
585	}
586
587	// === impl Format ===
588
589	impl Default for Format<Full, SystemTime> {
590	fn default() -> Self {
591	Format {
592	format: Full,
593	timer: SystemTime,
594	ansi: None,
595	display_timestamp: `true`,
596	display_target: `true`,
597	display_level: `true`,
598	display_thread_id: `false`,
599	display_thread_name: `false`,
600	display_filename: `false`,
601	display_line_number: `false`,
602	}
603	}
604	}
605
606	impl<F, T> Format<F, T> {
607	/// Use a less verbose output format.
608	///
609	/// See [`Compact`].
610	pub fn compact(self) -> Format<Compact, T> {
611	Format {
612	format: Compact,
613	timer: self.timer,
614	ansi: self.ansi,
615	display_target: self.display_target,
616	display_timestamp: self.display_timestamp,
617	display_level: self.display_level,
618	display_thread_id: self.display_thread_id,
619	display_thread_name: self.display_thread_name,
620	display_filename: self.display_filename,
621	display_line_number: self.display_line_number,
622	}
623	}
624
625	/// Use an excessively pretty, human-readable output format.
626	///
627	/// See [`Pretty`].
628	///
629	/// Note that this requires the "ansi" feature to be enabled.
630	///
631	/// # Options
632	///
633	/// [`Format::with_ansi`] can be used to disable ANSI terminal escape codes (which enable
634	/// formatting such as colors, bold, italic, etc) in event formatting. However, a field
635	/// formatter must be manually provided to avoid ANSI in the formatting of parent spans, like
636	/// so:
637	///
638	/// ```
639	/// # use tracing_subscriber::fmt::format;
640	/// tracing_subscriber::fmt()
641	/// .pretty()
642	/// .with_ansi(`false`)
643	/// .fmt_fields(format::PrettyFields::new().with_ansi(`false`))
644	/// // ... other settings ...
645	/// .init();
646	/// ```
647	#[cfg(feature = "ansi")]
648	#[cfg_attr(docsrs, doc(cfg(feature = "ansi")))]
649	pub fn pretty(self) -> Format<Pretty, T> {
650	Format {
651	format: Pretty::default(),
652	timer: self.timer,
653	ansi: self.ansi,
654	display_target: self.display_target,
655	display_timestamp: self.display_timestamp,
656	display_level: self.display_level,
657	display_thread_id: self.display_thread_id,
658	display_thread_name: self.display_thread_name,
659	display_filename: `true`,
660	display_line_number: `true`,
661	}
662	}
663
664	/// Use the full JSON format.
665	///
666	/// The full format includes fields from all entered spans.
667	///
668	/// # Example Output
669	///
670	/// ```ignore,json
671	/// {"timestamp":"Feb 20 11:28:15.096","level":"INFO","target":"mycrate","fields":{"message":"some message", "key": "value"}}
672	/// ```
673	///
674	/// # Options
675	///
676	/// - [`Format::flatten_event`] can be used to enable flattening event fields into the root
677	/// object.
678	#[cfg(feature = "json")]
679	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
680	pub fn json(self) -> Format<Json, T> {
681	Format {
682	format: Json::default(),
683	timer: self.timer,
684	ansi: self.ansi,
685	display_target: self.display_target,
686	display_timestamp: self.display_timestamp,
687	display_level: self.display_level,
688	display_thread_id: self.display_thread_id,
689	display_thread_name: self.display_thread_name,
690	display_filename: self.display_filename,
691	display_line_number: self.display_line_number,
692	}
693	}
694
695	/// Use the given [`timer`] for log message timestamps.
696	///
697	/// See [`time` module] for the provided timer implementations.
698	///
699	/// Note that using the `"time"` feature flag enables the
700	/// additional time formatters [`UtcTime`] and [`LocalTime`], which use the
701	/// [`time` crate] to provide more sophisticated timestamp formatting
702	/// options.
703	///
704	/// [`timer`]: super::time::FormatTime
705	/// [`time` module]: mod@super::time
706	/// [`UtcTime`]: super::time::UtcTime
707	/// [`LocalTime`]: super::time::LocalTime
708	/// [`time` crate]: https://docs.rs/time/0.3
709	pub fn with_timer<T2>(self, timer: T2) -> Format<F, T2> {
710	Format {
711	format: self.format,
712	timer,
713	ansi: self.ansi,
714	display_target: self.display_target,
715	display_timestamp: self.display_timestamp,
716	display_level: self.display_level,
717	display_thread_id: self.display_thread_id,
718	display_thread_name: self.display_thread_name,
719	display_filename: self.display_filename,
720	display_line_number: self.display_line_number,
721	}
722	}
723
724	/// Do not emit timestamps with log messages.
725	pub fn without_time(self) -> Format<F, ()> {
726	Format {
727	format: self.format,
728	timer: (),
729	ansi: self.ansi,
730	display_timestamp: `false`,
731	display_target: self.display_target,
732	display_level: self.display_level,
733	display_thread_id: self.display_thread_id,
734	display_thread_name: self.display_thread_name,
735	display_filename: self.display_filename,
736	display_line_number: self.display_line_number,
737	}
738	}
739
740	/// Enable ANSI terminal colors for formatted output.
741	pub fn with_ansi(self, ansi: bool) -> Format<F, T> {
742	Format {
743	ansi: Some(ansi),
744	..self
745	}
746	}
747
748	/// Sets whether or not an event's target is displayed.
749	pub fn with_target(self, display_target: bool) -> Format<F, T> {
750	Format {
751	display_target,
752	..self
753	}
754	}
755
756	/// Sets whether or not an event's level is displayed.
757	pub fn with_level(self, display_level: bool) -> Format<F, T> {
758	Format {
759	display_level,
760	..self
761	}
762	}
763
764	/// Sets whether or not the [thread ID] of the current thread is displayed
765	/// when formatting events.
766	///
767	/// [thread ID]: std::thread::ThreadId
768	pub fn with_thread_ids(self, display_thread_id: bool) -> Format<F, T> {
769	Format {
770	display_thread_id,
771	..self
772	}
773	}
774
775	/// Sets whether or not the [name] of the current thread is displayed
776	/// when formatting events.
777	///
778	/// [name]: std::thread#naming-threads
779	pub fn with_thread_names(self, display_thread_name: bool) -> Format<F, T> {
780	Format {
781	display_thread_name,
782	..self
783	}
784	}
785
786	/// Sets whether or not an event's [source code file path][file] is
787	/// displayed.
788	///
789	/// [file]: tracing_core::Metadata::file
790	pub fn with_file(self, display_filename: bool) -> Format<F, T> {
791	Format {
792	display_filename,
793	..self
794	}
795	}
796
797	/// Sets whether or not an event's [source code line number][line] is
798	/// displayed.
799	///
800	/// [line]: tracing_core::Metadata::line
801	pub fn with_line_number(self, display_line_number: bool) -> Format<F, T> {
802	Format {
803	display_line_number,
804	..self
805	}
806	}
807
808	/// Sets whether or not the source code location from which an event
809	/// originated is displayed.
810	///
811	/// This is equivalent to calling [`Format::with_file`] and
812	/// [`Format::with_line_number`] with the same value.
813	pub fn with_source_location(self, display_location: bool) -> Self {
814	self.with_line_number(display_location)
815	.with_file(display_location)
816	}
817
818	#[inline]
819	fn format_timestamp(&self, writer: &mut Writer<'_>) -> fmt::Result
820	where
821	T: FormatTime,
822	{
823	// If timestamps are disabled, do nothing.
824	if !self.display_timestamp {
825	return Ok(());
826	}
827
828	// If ANSI color codes are enabled, format the timestamp with ANSI
829	// colors.
830	#[cfg(feature = "ansi")]
831	{
832	if writer.has_ansi_escapes() {
833	let style = Style::new().dimmed();
834	write!(writer, "{}", style.prefix())?;
835
836	// If getting the timestamp failed, don't bail --- only bail on
837	// formatting errors.
838	if self.timer.format_time(writer).is_err() {
839	writer.write_str("<unknown time>")?;
840	}
841
842	write!(writer, "{} ", style.suffix())?;
843	return Ok(());
844	}
845	}
846
847	// Otherwise, just format the timestamp without ANSI formatting.
848	// If getting the timestamp failed, don't bail --- only bail on
849	// formatting errors.
850	if self.timer.format_time(writer).is_err() {
851	writer.write_str("<unknown time>")?;
852	}
853	writer.write_char(' ')
854	}
855	}
856
857	#[cfg(feature = "json")]
858	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
859	impl<T> Format<Json, T> {
860	/// Use the full JSON format with the event's event fields flattened.
861	///
862	/// # Example Output
863	///
864	/// ```ignore,json
865	/// {"timestamp":"Feb 20 11:28:15.096","level":"INFO","target":"mycrate", "message":"some message", "key": "value"}
866	/// ```
867	/// See [`Json`][super::format::Json].
868	#[cfg(feature = "json")]
869	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
870	pub fn flatten_event(mut self, flatten_event: bool) -> Format<Json, T> {
871	self.format.flatten_event(flatten_event);
872	self
873	}
874
875	/// Sets whether or not the formatter will include the current span in
876	/// formatted events.
877	///
878	/// See [`format::Json`][Json]
879	#[cfg(feature = "json")]
880	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
881	pub fn with_current_span(mut self, display_current_span: bool) -> Format<Json, T> {
882	self.format.with_current_span(display_current_span);
883	self
884	}
885
886	/// Sets whether or not the formatter will include a list (from root to
887	/// leaf) of all currently entered spans in formatted events.
888	///
889	/// See [`format::Json`][Json]
890	#[cfg(feature = "json")]
891	#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
892	pub fn with_span_list(mut self, display_span_list: bool) -> Format<Json, T> {
893	self.format.with_span_list(display_span_list);
894	self
895	}
896	}
897
898	impl<S, N, T> FormatEvent<S, N> for Format<Full, T>
899	where
900	S: Subscriber + for<'a> dynLookupSpan<'a>,
901	N: for<'a> dynFormatFields<'a> + 'static,
902	T: FormatTime,
903	{
904	fn format_event(
905	&self,
906	ctx: &FmtContext<'_, S, N>,
907	mut writer: Writer<'_>,
908	event: &Event<'_>,
909	) -> fmt::Result {
910	#[cfg(feature = "tracing-log")]
911	let normalized_meta = event.normalized_metadata();
912	#[cfg(feature = "tracing-log")]
913	let meta = normalized_meta.as_ref().unwrap_or_else(\|\| event.metadata());
914	#[cfg(not(feature = "tracing-log"))]
915	let meta = event.metadata();
916
917	// if the `Format` struct also* has an ANSI color configuration,*
918	// override the writer...the API for configuring ANSI color codes on the
919	// `Format` struct is deprecated, but we still need to honor those
920	// configurations.
921	if let Some(ansi) = self.ansi {
922	writer = writer.with_ansi(ansi);
923	}
924
925	self.format_timestamp(&mut writer)?;
926
927	if self.display_level {
928	let fmt_level = {
929	#[cfg(feature = "ansi")]
930	{
931	FmtLevel::new(meta.level(), writer.has_ansi_escapes())
932	}
933	#[cfg(not(feature = "ansi"))]
934	{
935	FmtLevel::new(meta.level())
936	}
937	};
938	write!(writer, "{} ", fmt_level)?;
939	}
940
941	if self.display_thread_name {
942	let current_thread = std::thread::current();
943	match current_thread.name() {
944	Some(name) => {
945	write!(writer, "{} ", FmtThreadName::new(name))?;
946	}
947	// fall-back to thread id when name is absent and ids are not enabled
948	None if !self.display_thread_id => {
949	write!(writer, "{:0>`2`?} ", current_thread.id())?;
950	}
951	_ => {}
952	}
953	}
954
955	if self.display_thread_id {
956	write!(writer, "{:0>`2`?} ", std::thread::current().id())?;
957	}
958
959	let dimmed = writer.dimmed();
960
961	if let Some(scope) = ctx.event_scope() {
962	let bold = writer.bold();
963
964	let mut seen = `false`;
965
966	for span in scope.from_root() {
967	write!(writer, "{}", bold.paint(span.metadata().name()))?;
968	seen = `true`;
969
970	let ext = span.extensions();
971	if let Some(fields) = &ext.get::<FormattedFields<N>>() {
972	if !fields.is_empty() {
973	write!(writer, "{}{}{}", bold.paint("{"), fields, bold.paint("}"))?;
974	}
975	}
976	write!(writer, "{}", dimmed.paint(":"))?;
977	}
978
979	if seen {
980	writer.write_char(' ')?;
981	}
982	};
983
984	if self.display_target {
985	write!(
986	writer,
987	"{}{} ",
988	dimmed.paint(meta.target()),
989	dimmed.paint(":")
990	)?;
991	}
992
993	let line_number = if self.display_line_number {
994	meta.line()
995	} else {
996	None
997	};
998
999	if self.display_filename {
1000	if let Some(filename) = meta.file() {
1001	write!(
1002	writer,
1003	"{}{}{}",
1004	dimmed.paint(filename),
1005	dimmed.paint(":"),
1006	if line_number.is_some() { "" } else { " " }
1007	)?;
1008	}
1009	}
1010
1011	if let Some(line_number) = line_number {
1012	write!(
1013	writer,
1014	"{}{}:{} ",
1015	dimmed.prefix(),
1016	line_number,
1017	dimmed.suffix()
1018	)?;
1019	}
1020
1021	ctx.format_fields(writer.by_ref(), event)?;
1022	writeln!(writer)
1023	}
1024	}
1025
1026	impl<S, N, T> FormatEvent<S, N> for Format<Compact, T>
1027	where
1028	S: Subscriber + for<'a> dynLookupSpan<'a>,
1029	N: for<'a> dynFormatFields<'a> + 'static,
1030	T: FormatTime,
1031	{
1032	fn format_event(
1033	&self,
1034	ctx: &FmtContext<'_, S, N>,
1035	mut writer: Writer<'_>,
1036	event: &Event<'_>,
1037	) -> fmt::Result {
1038	#[cfg(feature = "tracing-log")]
1039	let normalized_meta = event.normalized_metadata();
1040	#[cfg(feature = "tracing-log")]
1041	let meta = normalized_meta.as_ref().unwrap_or_else(\|\| event.metadata());
1042	#[cfg(not(feature = "tracing-log"))]
1043	let meta = event.metadata();
1044
1045	// if the `Format` struct also* has an ANSI color configuration,*
1046	// override the writer...the API for configuring ANSI color codes on the
1047	// `Format` struct is deprecated, but we still need to honor those
1048	// configurations.
1049	if let Some(ansi) = self.ansi {
1050	writer = writer.with_ansi(ansi);
1051	}
1052
1053	self.format_timestamp(&mut writer)?;
1054
1055	if self.display_level {
1056	let fmt_level = {
1057	#[cfg(feature = "ansi")]
1058	{
1059	FmtLevel::new(meta.level(), writer.has_ansi_escapes())
1060	}
1061	#[cfg(not(feature = "ansi"))]
1062	{
1063	FmtLevel::new(meta.level())
1064	}
1065	};
1066	write!(writer, "{} ", fmt_level)?;
1067	}
1068
1069	if self.display_thread_name {
1070	let current_thread = std::thread::current();
1071	match current_thread.name() {
1072	Some(name) => {
1073	write!(writer, "{} ", FmtThreadName::new(name))?;
1074	}
1075	// fall-back to thread id when name is absent and ids are not enabled
1076	None if !self.display_thread_id => {
1077	write!(writer, "{:0>`2`?} ", current_thread.id())?;
1078	}
1079	_ => {}
1080	}
1081	}
1082
1083	if self.display_thread_id {
1084	write!(writer, "{:0>`2`?} ", std::thread::current().id())?;
1085	}
1086
1087	let fmt_ctx = {
1088	#[cfg(feature = "ansi")]
1089	{
1090	FmtCtx::new(ctx, event.parent(), writer.has_ansi_escapes())
1091	}
1092	#[cfg(not(feature = "ansi"))]
1093	{
1094	FmtCtx::new(&ctx, event.parent())
1095	}
1096	};
1097	write!(writer, "{}", fmt_ctx)?;
1098
1099	let dimmed = writer.dimmed();
1100
1101	let mut needs_space = `false`;
1102	if self.display_target {
1103	write!(
1104	writer,
1105	"{}{}",
1106	dimmed.paint(meta.target()),
1107	dimmed.paint(":")
1108	)?;
1109	needs_space = `true`;
1110	}
1111
1112	if self.display_filename {
1113	if let Some(filename) = meta.file() {
1114	if self.display_target {
1115	writer.write_char(' ')?;
1116	}
1117	write!(writer, "{}{}", dimmed.paint(filename), dimmed.paint(":"))?;
1118	needs_space = `true`;
1119	}
1120	}
1121
1122	if self.display_line_number {
1123	if let Some(line_number) = meta.line() {
1124	write!(
1125	writer,
1126	"{}{}{}{}",
1127	dimmed.prefix(),
1128	line_number,
1129	dimmed.suffix(),
1130	dimmed.paint(":")
1131	)?;
1132	needs_space = `true`;
1133	}
1134	}
1135
1136	if needs_space {
1137	writer.write_char(' ')?;
1138	}
1139
1140	ctx.format_fields(writer.by_ref(), event)?;
1141
1142	for span in ctx
1143	.event_scope()
1144	.into_iter()
1145	.flat_map(crate::registry::Scope::from_root)
1146	{
1147	let exts = span.extensions();
1148	if let Some(fields) = exts.get::<FormattedFields<N>>() {
1149	if !fields.is_empty() {
1150	write!(writer, " {}", dimmed.paint(&fields.fields))?;
1151	}
1152	}
1153	}
1154	writeln!(writer)
1155	}
1156	}
1157
1158	// === impl FormatFields ===
1159	impl<'writer, M> FormatFields<'writer> for M
1160	where
1161	M: MakeOutput<Writer<'writer>, fmt::Result>,
1162	M::Visitor: VisitFmt + VisitOutput<fmt::Result>,
1163	{
1164	fn format_fields<R: RecordFields>(&self, writer: Writer<'writer>, fields: R) -> fmt::Result {
1165	let mut v: impl VisitFmt + VisitOutput<…> = self.make_visitor(target:writer);
1166	fields.record(&mut v);
1167	v.finish()
1168	}
1169	}
1170
1171	/// The default [`FormatFields`] implementation.
1172	///
1173	#[derive(Debug)]
1174	pub struct DefaultFields {
1175	// reserve the ability to add fields to this without causing a breaking
1176	// change in the future.
1177	_private: (),
1178	}
1179
1180	/// The [visitor] produced by [`DefaultFields`]'s [`MakeVisitor`] implementation.
1181	///
1182	/// [visitor]: super::super::field::Visit
1183	/// [`MakeVisitor`]: super::super::field::MakeVisitor
1184	#[derive(Debug)]
1185	pub struct DefaultVisitor<'a> {
1186	writer: Writer<'a>,
1187	is_empty: bool,
1188	result: fmt::Result,
1189	}
1190
1191	impl DefaultFields {
1192	/// Returns a new default [`FormatFields`] implementation.
1193	///
1194	pub fn new() -> Self {
1195	Self { _private: () }
1196	}
1197	}
1198
1199	impl Default for DefaultFields {
1200	fn default() -> Self {
1201	Self::new()
1202	}
1203	}
1204
1205	impl<'a> MakeVisitor<Writer<'a>> for DefaultFields {
1206	type Visitor = DefaultVisitor<'a>;
1207
1208	#[inline]
1209	fn make_visitor(&self, target: Writer<'a>) -> Self::Visitor {
1210	DefaultVisitor::new(writer:target, is_empty:`true`)
1211	}
1212	}
1213
1214	// === impl DefaultVisitor ===
1215
1216	impl<'a> DefaultVisitor<'a> {
1217	/// Returns a new default visitor that formats to the provided `writer`.
1218	///
1219	/// # Arguments
1220	/// - `writer`: the writer to format to.
1221	/// - `is_empty`: whether or not any fields have been previously written to
1222	/// that writer.
1223	pub fn new(writer: Writer<'a>, is_empty: bool) -> Self {
1224	Self {
1225	writer,
1226	is_empty,
1227	result: Ok(()),
1228	}
1229	}
1230
1231	fn maybe_pad(&mut self) {
1232	if self.is_empty {
1233	self.is_empty = `false`;
1234	} else {
1235	self.result = write!(self.writer, " ");
1236	}
1237	}
1238	}
1239
1240	impl<'a> field::Visit for DefaultVisitor<'a> {
1241	fn record_str(&mut self, field: &Field, value: &str) {
1242	if self.result.is_err() {
1243	return;
1244	}
1245
1246	if field.name() == "message" {
1247	self.record_debug(field, &format_args!("{}", value))
1248	} else {
1249	self.record_debug(field, &value)
1250	}
1251	}
1252
1253	fn record_error(&mut self, field: &Field, value: &(dyn std::error::Error + 'static)) {
1254	if let Some(source) = value.source() {
1255	let italic = self.writer.italic();
1256	self.record_debug(
1257	field,
1258	&format_args!(
1259	"{} {}{}{}{}",
1260	value,
1261	italic.paint(field.name()),
1262	italic.paint(".sources"),
1263	self.writer.dimmed().paint("="),
1264	ErrorSourceList(source)
1265	),
1266	)
1267	} else {
1268	self.record_debug(field, &format_args!("{}", value))
1269	}
1270	}
1271
1272	fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
1273	if self.result.is_err() {
1274	return;
1275	}
1276
1277	self.maybe_pad();
1278	self.result = match field.name() {
1279	"message" => write!(self.writer, "{:?}", value),
1280	// Skip fields that are actually log metadata that have already been handled
1281	#[cfg(feature = "tracing-log")]
1282	name if name.starts_with("log.") => Ok(()),
1283	name if name.starts_with("r#") => write!(
1284	self.writer,
1285	"{}{}{:?}",
1286	self.writer.italic().paint(&name[`2`..]),
1287	self.writer.dimmed().paint("="),
1288	value
1289	),
1290	name => write!(
1291	self.writer,
1292	"{}{}{:?}",
1293	self.writer.italic().paint(name),
1294	self.writer.dimmed().paint("="),
1295	value
1296	),
1297	};
1298	}
1299	}
1300
1301	impl<'a> crate::field::VisitOutput<fmt::Result> for DefaultVisitor<'a> {
1302	fn finish(self) -> fmt::Result {
1303	self.result
1304	}
1305	}
1306
1307	impl<'a> crate::field::VisitFmt for DefaultVisitor<'a> {
1308	fn writer(&mut self) -> &mut dyn fmt::Write {
1309	&mut self.writer
1310	}
1311	}
1312
1313	/// Renders an error into a list of sources, including* the error*
1314	struct ErrorSourceList<'a>(&'a (dyn std::error::Error + 'static));
1315
1316	impl<'a> Display for ErrorSourceList<'a> {
1317	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1318	let mut list: DebugList<'_, '_> = f.debug_list();
1319	let mut curr: Option<&'a dyn Error> = Some(self.0);
1320	while let Some(curr_err: &'a dyn Error) = curr {
1321	list.entry(&format_args!("{}", curr_err));
1322	curr = curr_err.source();
1323	}
1324	list.finish()
1325	}
1326	}
1327
1328	struct FmtCtx<'a, S, N> {
1329	ctx: &'a FmtContext<'a, S, N>,
1330	span: Option<&'a span::Id>,
1331	#[cfg(feature = "ansi")]
1332	ansi: bool,
1333	}
1334
1335	impl<'a, S, N: 'a> FmtCtx<'a, S, N>
1336	where
1337	S: Subscriber + for<'lookup> dynLookupSpan<'lookup>,
1338	N: for<'writer> dynFormatFields<'writer> + 'static,
1339	{
1340	#[cfg(feature = "ansi")]
1341	pub(crate) fn new(
1342	ctx: &'a FmtContext<'_, S, N>,
1343	span: Option<&'a span::Id>,
1344	ansi: bool,
1345	) -> Self {
1346	Self { ctx, span, ansi }
1347	}
1348
1349	#[cfg(not(feature = "ansi"))]
1350	pub(crate) fn new(ctx: &'a FmtContext<'_, S, N>, span: Option<&'a span::Id>) -> Self {
1351	Self { ctx, span }
1352	}
1353
1354	fn bold(&self) -> Style {
1355	#[cfg(feature = "ansi")]
1356	{
1357	if self.ansi {
1358	return Style::new().bold();
1359	}
1360	}
1361
1362	Style::new()
1363	}
1364	}
1365
1366	impl<'a, S, N: 'a> fmt::Display for FmtCtx<'a, S, N>
1367	where
1368	S: Subscriber + for<'lookup> dynLookupSpan<'lookup>,
1369	N: for<'writer> dynFormatFields<'writer> + 'static,
1370	{
1371	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1372	let bold: Style = self.bold();
1373	let mut seen: bool = `false`;
1374
1375	let span: Option> = self
1376	.span
1377	.and_then(\|id: &'a Id\| self.ctx.ctx.span(id))
1378	.or_else(\|\| self.ctx.ctx.lookup_current());
1379
1380	let scope: impl Iterator> = span.into_iter().flat_map(\|span: SpanRef<'_, S>\| span.scope().from_root());
1381
1382	for span: SpanRef<'_, S> in scope {
1383	seen = `true`;
1384	write!(f, "{}:", bold.paint(span.metadata().name()))?;
1385	}
1386
1387	if seen {
1388	f.write_char(' ')?;
1389	}
1390	Ok(())
1391	}
1392	}
1393
1394	#[cfg(not(feature = "ansi"))]
1395	struct Style;
1396
1397	#[cfg(not(feature = "ansi"))]
1398	impl Style {
1399	fn new() -> Self {
1400	Style
1401	}
1402
1403	fn bold(self) -> Self {
1404	self
1405	}
1406
1407	fn paint(&self, d: impl fmt::Display) -> impl fmt::Display {
1408	d
1409	}
1410
1411	fn prefix(&self) -> impl fmt::Display {
1412	""
1413	}
1414
1415	fn suffix(&self) -> impl fmt::Display {
1416	""
1417	}
1418	}
1419
1420	struct FmtThreadName<'a> {
1421	name: &'a str,
1422	}
1423
1424	impl<'a> FmtThreadName<'a> {
1425	pub(crate) fn new(name: &'a str) -> Self {
1426	Self { name }
1427	}
1428	}
1429
1430	impl<'a> fmt::Display for FmtThreadName<'a> {
1431	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1432	use std::sync::atomic::{
1433	AtomicUsize,
1434	Ordering::{AcqRel, Acquire, Relaxed},
1435	};
1436
1437	// Track the longest thread name length we've seen so far in an atomic,
1438	// so that it can be updated by any thread.
1439	static MAX_LEN: AtomicUsize = AtomicUsize::new(`0`);
1440	let len = self.name.len();
1441	// Snapshot the current max thread name length.
1442	let mut max_len = MAX_LEN.load(Relaxed);
1443
1444	while len > max_len {
1445	// Try to set a new max length, if it is still the value we took a
1446	// snapshot of.
1447	match MAX_LEN.compare_exchange(max_len, len, AcqRel, Acquire) {
1448	// We successfully set the new max value
1449	Ok(_) => break,
1450	// Another thread set a new max value since we last observed
1451	// it! It's possible that the new length is actually longer than
1452	// ours, so we'll loop again and check whether our length is
1453	// still the longest. If not, we'll just use the newer value.
1454	Err(actual) => max_len = actual,
1455	}
1456	}
1457
1458	// pad thread name using `max_len`
1459	write!(f, "{:>width$}", self.name, width = max_len)
1460	}
1461	}
1462
1463	struct FmtLevel<'a> {
1464	level: &'a Level,
1465	#[cfg(feature = "ansi")]
1466	ansi: bool,
1467	}
1468
1469	impl<'a> FmtLevel<'a> {
1470	#[cfg(feature = "ansi")]
1471	pub(crate) fn new(level: &'a Level, ansi: bool) -> Self {
1472	Self { level, ansi }
1473	}
1474
1475	#[cfg(not(feature = "ansi"))]
1476	pub(crate) fn new(level: &'a Level) -> Self {
1477	Self { level }
1478	}
1479	}
1480
1481	const TRACE_STR: &str = "TRACE";
1482	const DEBUG_STR: &str = "DEBUG";
1483	const INFO_STR: &str = " INFO";
1484	const WARN_STR: &str = " WARN";
1485	const ERROR_STR: &str = "ERROR";
1486
1487	#[cfg(not(feature = "ansi"))]
1488	impl<'a> fmt::Display for FmtLevel<'a> {
1489	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1490	match *self.level {
1491	Level::TRACE => f.pad(TRACE_STR),
1492	Level::DEBUG => f.pad(DEBUG_STR),
1493	Level::INFO => f.pad(INFO_STR),
1494	Level::WARN => f.pad(WARN_STR),
1495	Level::ERROR => f.pad(ERROR_STR),
1496	}
1497	}
1498	}
1499
1500	#[cfg(feature = "ansi")]
1501	impl<'a> fmt::Display for FmtLevel<'a> {
1502	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1503	if self.ansi {
1504	match *self.level {
1505	Level::TRACE => write!(f, "{}", Color::Purple.paint(TRACE_STR)),
1506	Level::DEBUG => write!(f, "{}", Color::Blue.paint(DEBUG_STR)),
1507	Level::INFO => write!(f, "{}", Color::Green.paint(INFO_STR)),
1508	Level::WARN => write!(f, "{}", Color::Yellow.paint(WARN_STR)),
1509	Level::ERROR => write!(f, "{}", Color::Red.paint(ERROR_STR)),
1510	}
1511	} else {
1512	match *self.level {
1513	Level::TRACE => f.pad(TRACE_STR),
1514	Level::DEBUG => f.pad(DEBUG_STR),
1515	Level::INFO => f.pad(INFO_STR),
1516	Level::WARN => f.pad(WARN_STR),
1517	Level::ERROR => f.pad(ERROR_STR),
1518	}
1519	}
1520	}
1521	}
1522
1523	// === impl FieldFn ===
1524
1525	impl<'a, F> MakeVisitor<Writer<'a>> for FieldFn<F>
1526	where
1527	F: Fn(&mut Writer<'a>, &Field, &dyn fmt::Debug) -> fmt::Result + Clone,
1528	{
1529	type Visitor = FieldFnVisitor<'a, F>;
1530
1531	fn make_visitor(&self, writer: Writer<'a>) -> Self::Visitor {
1532	FieldFnVisitor {
1533	writer,
1534	f: self.0.clone(),
1535	result: Ok(()),
1536	}
1537	}
1538	}
1539
1540	impl<'a, F> Visit for FieldFnVisitor<'a, F>
1541	where
1542	F: Fn(&mut Writer<'a>, &Field, &dyn fmt::Debug) -> fmt::Result,
1543	{
1544	fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
1545	if self.result.is_ok() {
1546	self.result = (self.f)(&mut self.writer, field, value)
1547	}
1548	}
1549	}
1550
1551	impl<'a, F> VisitOutput<fmt::Result> for FieldFnVisitor<'a, F>
1552	where
1553	F: Fn(&mut Writer<'a>, &Field, &dyn fmt::Debug) -> fmt::Result,
1554	{
1555	fn finish(self) -> fmt::Result {
1556	self.result
1557	}
1558	}
1559
1560	impl<'a, F> VisitFmt for FieldFnVisitor<'a, F>
1561	where
1562	F: Fn(&mut Writer<'a>, &Field, &dyn fmt::Debug) -> fmt::Result,
1563	{
1564	fn writer(&mut self) -> &mut dyn fmt::Write {
1565	&mut self.writer
1566	}
1567	}
1568
1569	impl<'a, F> fmt::Debug for FieldFnVisitor<'a, F> {
1570	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1571	f&mut DebugStruct<'_, '_>.debug_struct("FieldFnVisitor")
1572	.field("f", &format_args!("{}", std::any::type_name::<F>()))
1573	.field("writer", &self.writer)
1574	.field(name:"result", &self.result)
1575	.finish()
1576	}
1577	}
1578
1579	// === printing synthetic Span events ===
1580
1581	/// Configures what points in the span lifecycle are logged as events.
1582	///
1583	/// See also [`with_span_events`](super::SubscriberBuilder.html::with_span_events).
1584	#[derive(Clone, Eq, PartialEq, Ord, PartialOrd)]
1585	pub struct FmtSpan(u8);
1586
1587	impl FmtSpan {
1588	/// one event when span is created
1589	pub const NEW: FmtSpan = FmtSpan(`1` << `0`);
1590	/// one event per enter of a span
1591	pub const ENTER: FmtSpan = FmtSpan(`1` << `1`);
1592	/// one event per exit of a span
1593	pub const EXIT: FmtSpan = FmtSpan(`1` << `2`);
1594	/// one event when the span is dropped
1595	pub const CLOSE: FmtSpan = FmtSpan(`1` << `3`);
1596
1597	/// spans are ignored (this is the default)
1598	pub const NONE: FmtSpan = FmtSpan(`0`);
1599	/// one event per enter/exit of a span
1600	pub const ACTIVE: FmtSpan = FmtSpan(FmtSpan::ENTER.0 \| FmtSpan::EXIT.0);
1601	/// events at all points (new, enter, exit, drop)
1602	pub const FULL: FmtSpan =
1603	FmtSpan(FmtSpan::NEW.0 \| FmtSpan::ENTER.0 \| FmtSpan::EXIT.0 \| FmtSpan::CLOSE.0);
1604
1605	/// Check whether or not a certain flag is set for this [`FmtSpan`]
1606	fn contains(&self, other: FmtSpan) -> bool {
1607	self.clone() & other.clone() == other
1608	}
1609	}
1610
1611	macro_rules! impl_fmt_span_bit_op {
1612	($trait:ident, $func:ident, $op:tt) => {
1613	impl std::ops::$trait for FmtSpan {
1614	type Output = FmtSpan;
1615
1616	fn $func(self, rhs: Self) -> Self::Output {
1617	FmtSpan(self.`0` $op rhs.`0`)
1618	}
1619	}
1620	};
1621	}
1622
1623	macro_rules! impl_fmt_span_bit_assign_op {
1624	($trait:ident, $func:ident, $op:tt) => {
1625	impl std::ops::$trait for FmtSpan {
1626	fn $func(&mut self, rhs: Self) {
1627	*self = FmtSpan(self.`0` $op rhs.`0`)
1628	}
1629	}
1630	};
1631	}
1632
1633	impl_fmt_span_bit_op!(BitAnd, bitand, &);
1634	impl_fmt_span_bit_op!(BitOr, bitor, \|);
1635	impl_fmt_span_bit_op!(BitXor, bitxor, ^);
1636
1637	impl_fmt_span_bit_assign_op!(BitAndAssign, bitand_assign, &);
1638	impl_fmt_span_bit_assign_op!(BitOrAssign, bitor_assign, \|);
1639	impl_fmt_span_bit_assign_op!(BitXorAssign, bitxor_assign, ^);
1640
1641	impl Debug for FmtSpan {
1642	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1643	let mut wrote_flag = `false`;
1644	let mut write_flags = \|flag, flag_str\| -> fmt::Result {
1645	if self.contains(flag) {
1646	if wrote_flag {
1647	f.write_str(" \| ")?;
1648	}
1649
1650	f.write_str(flag_str)?;
1651	wrote_flag = `true`;
1652	}
1653
1654	Ok(())
1655	};
1656
1657	if FmtSpan::NONE \| self.clone() == FmtSpan::NONE {
1658	f.write_str("FmtSpan::NONE")?;
1659	} else {
1660	write_flags(FmtSpan::NEW, "FmtSpan::NEW")?;
1661	write_flags(FmtSpan::ENTER, "FmtSpan::ENTER")?;
1662	write_flags(FmtSpan::EXIT, "FmtSpan::EXIT")?;
1663	write_flags(FmtSpan::CLOSE, "FmtSpan::CLOSE")?;
1664	}
1665
1666	Ok(())
1667	}
1668	}
1669
1670	pub(super) struct FmtSpanConfig {
1671	pub(super) kind: FmtSpan,
1672	pub(super) fmt_timing: bool,
1673	}
1674
1675	impl FmtSpanConfig {
1676	pub(super) fn without_time(self) -> Self {
1677	Self {
1678	kind: self.kind,
1679	fmt_timing: `false`,
1680	}
1681	}
1682	pub(super) fn with_kind(self, kind: FmtSpan) -> Self {
1683	Self {
1684	kind,
1685	fmt_timing: self.fmt_timing,
1686	}
1687	}
1688	pub(super) fn trace_new(&self) -> bool {
1689	self.kind.contains(FmtSpan::NEW)
1690	}
1691	pub(super) fn trace_enter(&self) -> bool {
1692	self.kind.contains(FmtSpan::ENTER)
1693	}
1694	pub(super) fn trace_exit(&self) -> bool {
1695	self.kind.contains(FmtSpan::EXIT)
1696	}
1697	pub(super) fn trace_close(&self) -> bool {
1698	self.kind.contains(FmtSpan::CLOSE)
1699	}
1700	}
1701
1702	impl Debug for FmtSpanConfig {
1703	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1704	self.kind.fmt(f)
1705	}
1706	}
1707
1708	impl Default for FmtSpanConfig {
1709	fn default() -> Self {
1710	Self {
1711	kind: FmtSpan::NONE,
1712	fmt_timing: `true`,
1713	}
1714	}
1715	}
1716
1717	pub(super) struct TimingDisplay(pub(super) u64);
1718	impl Display for TimingDisplay {
1719	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1720	let mut t: f64 = self.0 as f64;
1721	for unit: &&str in ["ns", "µs", "ms", "s"].iter() {
1722	if t < `10.0` {
1723	return write!(f, "{:.`2`}{}", t, unit);
1724	} else if t < `100.0` {
1725	return write!(f, "{:.`1`}{}", t, unit);
1726	} else if t < `1000.0` {
1727	return write!(f, "{:.`0`}{}", t, unit);
1728	}
1729	t /= `1000.0`;
1730	}
1731	write!(f, "{:.`0`}s", t * `1000.0`)
1732	}
1733	}
1734
1735	#[cfg(test)]
1736	pub(super) mod test {
1737	use crate::fmt::{test::MockMakeWriter, time::FormatTime};
1738	use tracing::{
1739	self,
1740	dispatcher::{set_default, Dispatch},
1741	subscriber::with_default,
1742	};
1743
1744	use super::*;
1745
1746	use regex::Regex;
1747	use std::{fmt, path::Path};
1748
1749	pub(crate) struct MockTime;
1750	impl FormatTime for MockTime {
1751	fn format_time(&self, w: &mut Writer<'_>) -> fmt::Result {
1752	write!(w, "fake time")
1753	}
1754	}
1755
1756	#[test]
1757	fn disable_everything() {
1758	// This test reproduces https://github.com/tokio-rs/tracing/issues/1354
1759	let make_writer = MockMakeWriter::default();
1760	let subscriber = crate::fmt::Subscriber::builder()
1761	.with_writer(make_writer.clone())
1762	.without_time()
1763	.with_level(`false`)
1764	.with_target(`false`)
1765	.with_thread_ids(`false`)
1766	.with_thread_names(`false`);
1767	#[cfg(feature = "ansi")]
1768	let subscriber = subscriber.with_ansi(`false`);
1769	assert_info_hello(subscriber, make_writer, "hello`\n`")
1770	}
1771
1772	fn test_ansi<T>(
1773	is_ansi: bool,
1774	expected: &str,
1775	builder: crate::fmt::SubscriberBuilder<DefaultFields, Format<T>>,
1776	) where
1777	Format<T, MockTime>: FormatEvent<crate::Registry, DefaultFields>,
1778	T: Send + Sync + 'static,
1779	{
1780	let make_writer = MockMakeWriter::default();
1781	let subscriber = builder
1782	.with_writer(make_writer.clone())
1783	.with_ansi(is_ansi)
1784	.with_timer(MockTime);
1785	run_test(subscriber, make_writer, expected)
1786	}
1787
1788	#[cfg(not(feature = "ansi"))]
1789	fn test_without_ansi<T>(
1790	expected: &str,
1791	builder: crate::fmt::SubscriberBuilder<DefaultFields, Format<T>>,
1792	) where
1793	Format<T, MockTime>: FormatEvent<crate::Registry, DefaultFields>,
1794	T: Send + Sync,
1795	{
1796	let make_writer = MockMakeWriter::default();
1797	let subscriber = builder.with_writer(make_writer).with_timer(MockTime);
1798	run_test(subscriber, make_writer, expected)
1799	}
1800
1801	fn test_without_level<T>(
1802	expected: &str,
1803	builder: crate::fmt::SubscriberBuilder<DefaultFields, Format<T>>,
1804	) where
1805	Format<T, MockTime>: FormatEvent<crate::Registry, DefaultFields>,
1806	T: Send + Sync + 'static,
1807	{
1808	let make_writer = MockMakeWriter::default();
1809	let subscriber = builder
1810	.with_writer(make_writer.clone())
1811	.with_level(`false`)
1812	.with_ansi(`false`)
1813	.with_timer(MockTime);
1814	run_test(subscriber, make_writer, expected);
1815	}
1816
1817	#[test]
1818	fn with_line_number_and_file_name() {
1819	let make_writer = MockMakeWriter::default();
1820	let subscriber = crate::fmt::Subscriber::builder()
1821	.with_writer(make_writer.clone())
1822	.with_file(`true`)
1823	.with_line_number(`true`)
1824	.with_level(`false`)
1825	.with_ansi(`false`)
1826	.with_timer(MockTime);
1827
1828	let expected = Regex::new(&format!(
1829	"^fake time tracing_subscriber::fmt::format::test: {}:[0-9]+: hello`\n`$",
1830	current_path()
1831	// if we're on Windows, the path might contain backslashes, which
1832	// have to be escpaed before compiling the regex.
1833	.replace('`\\`', "`\\\\`")
1834	))
1835	.unwrap();
1836	let _default = set_default(&subscriber.into());
1837	tracing::info!("hello");
1838	let res = make_writer.get_string();
1839	assert!(expected.is_match(&res));
1840	}
1841
1842	#[test]
1843	fn with_line_number() {
1844	let make_writer = MockMakeWriter::default();
1845	let subscriber = crate::fmt::Subscriber::builder()
1846	.with_writer(make_writer.clone())
1847	.with_line_number(`true`)
1848	.with_level(`false`)
1849	.with_ansi(`false`)
1850	.with_timer(MockTime);
1851
1852	let expected =
1853	Regex::new("^fake time tracing_subscriber::fmt::format::test: [0-9]+: hello`\n`$")
1854	.unwrap();
1855	let _default = set_default(&subscriber.into());
1856	tracing::info!("hello");
1857	let res = make_writer.get_string();
1858	assert!(expected.is_match(&res));
1859	}
1860
1861	#[test]
1862	fn with_filename() {
1863	let make_writer = MockMakeWriter::default();
1864	let subscriber = crate::fmt::Subscriber::builder()
1865	.with_writer(make_writer.clone())
1866	.with_file(`true`)
1867	.with_level(`false`)
1868	.with_ansi(`false`)
1869	.with_timer(MockTime);
1870	let expected = &format!(
1871	"fake time tracing_subscriber::fmt::format::test: {}: hello`\n`",
1872	current_path(),
1873	);
1874	assert_info_hello(subscriber, make_writer, expected);
1875	}
1876
1877	#[test]
1878	fn with_thread_ids() {
1879	let make_writer = MockMakeWriter::default();
1880	let subscriber = crate::fmt::Subscriber::builder()
1881	.with_writer(make_writer.clone())
1882	.with_thread_ids(`true`)
1883	.with_ansi(`false`)
1884	.with_timer(MockTime);
1885	let expected =
1886	"fake time INFO ThreadId(NUMERIC) tracing_subscriber::fmt::format::test: hello`\n`";
1887
1888	assert_info_hello_ignore_numeric(subscriber, make_writer, expected);
1889	}
1890
1891	#[test]
1892	fn pretty_default() {
1893	let make_writer = MockMakeWriter::default();
1894	let subscriber = crate::fmt::Subscriber::builder()
1895	.pretty()
1896	.with_writer(make_writer.clone())
1897	.with_ansi(`false`)
1898	.with_timer(MockTime);
1899	let expected = format!(
1900	r#" fake time INFO tracing_subscriber::fmt::format::test: hello
1901	at {}:NUMERIC
1902
1903	"#,
1904	file!()
1905	);
1906
1907	assert_info_hello_ignore_numeric(subscriber, make_writer, &expected)
1908	}
1909
1910	fn assert_info_hello(subscriber: impl Into<Dispatch>, buf: MockMakeWriter, expected: &str) {
1911	let _default = set_default(&subscriber.into());
1912	tracing::info!("hello");
1913	let result = buf.get_string();
1914
1915	assert_eq!(expected, result)
1916	}
1917
1918	// When numeric characters are used they often form a non-deterministic value as they usually represent things like a thread id or line number.
1919	// This assert method should be used when non-deterministic numeric characters are present.
1920	fn assert_info_hello_ignore_numeric(
1921	subscriber: impl Into<Dispatch>,
1922	buf: MockMakeWriter,
1923	expected: &str,
1924	) {
1925	let _default = set_default(&subscriber.into());
1926	tracing::info!("hello");
1927
1928	let regex = Regex::new("[0-9]+").unwrap();
1929	let result = buf.get_string();
1930	let result_cleaned = regex.replace_all(&result, "NUMERIC");
1931
1932	assert_eq!(expected, result_cleaned)
1933	}
1934
1935	fn test_overridden_parents<T>(
1936	expected: &str,
1937	builder: crate::fmt::SubscriberBuilder<DefaultFields, Format<T>>,
1938	) where
1939	Format<T, MockTime>: FormatEvent<crate::Registry, DefaultFields>,
1940	T: Send + Sync + 'static,
1941	{
1942	let make_writer = MockMakeWriter::default();
1943	let subscriber = builder
1944	.with_writer(make_writer.clone())
1945	.with_level(`false`)
1946	.with_ansi(`false`)
1947	.with_timer(MockTime)
1948	.finish();
1949
1950	with_default(subscriber, \|\| {
1951	let span1 = tracing::info_span!("span1", span = `1`);
1952	let span2 = tracing::info_span!(parent: &span1, "span2", span = `2`);
1953	tracing::info!(parent: &span2, "hello");
1954	});
1955	assert_eq!(expected, make_writer.get_string());
1956	}
1957
1958	fn test_overridden_parents_in_scope<T>(
1959	expected1: &str,
1960	expected2: &str,
1961	builder: crate::fmt::SubscriberBuilder<DefaultFields, Format<T>>,
1962	) where
1963	Format<T, MockTime>: FormatEvent<crate::Registry, DefaultFields>,
1964	T: Send + Sync + 'static,
1965	{
1966	let make_writer = MockMakeWriter::default();
1967	let subscriber = builder
1968	.with_writer(make_writer.clone())
1969	.with_level(`false`)
1970	.with_ansi(`false`)
1971	.with_timer(MockTime)
1972	.finish();
1973
1974	with_default(subscriber, \|\| {
1975	let span1 = tracing::info_span!("span1", span = `1`);
1976	let span2 = tracing::info_span!(parent: &span1, "span2", span = `2`);
1977	let span3 = tracing::info_span!("span3", span = `3`);
1978	let _e3 = span3.enter();
1979
1980	tracing::info!("hello");
1981	assert_eq!(expected1, make_writer.get_string().as_str());
1982
1983	tracing::info!(parent: &span2, "hello");
1984	assert_eq!(expected2, make_writer.get_string().as_str());
1985	});
1986	}
1987
1988	fn run_test(subscriber: impl Into<Dispatch>, buf: MockMakeWriter, expected: &str) {
1989	let _default = set_default(&subscriber.into());
1990	tracing::info!("hello");
1991	assert_eq!(expected, buf.get_string())
1992	}
1993
1994	mod default {
1995	use super::*;
1996
1997	#[test]
1998	fn with_thread_ids() {
1999	let make_writer = MockMakeWriter::default();
2000	let subscriber = crate::fmt::Subscriber::builder()
2001	.with_writer(make_writer.clone())
2002	.with_thread_ids(`true`)
2003	.with_ansi(`false`)
2004	.with_timer(MockTime);
2005	let expected =
2006	"fake time INFO ThreadId(NUMERIC) tracing_subscriber::fmt::format::test: hello`\n`";
2007
2008	assert_info_hello_ignore_numeric(subscriber, make_writer, expected);
2009	}
2010
2011	#[cfg(feature = "ansi")]
2012	#[test]
2013	fn with_ansi_true() {
2014	let expected = "`\u{1b}`[2mfake time`\u{1b}`[0m `\u{1b}`[32m INFO`\u{1b}`[0m `\u{1b}`[2mtracing_subscriber::fmt::format::test`\u{1b}`[0m`\u{1b}`[2m:`\u{1b}`[0m hello`\n`";
2015	test_ansi(`true`, expected, crate::fmt::Subscriber::builder());
2016	}
2017
2018	#[cfg(feature = "ansi")]
2019	#[test]
2020	fn with_ansi_false() {
2021	let expected = "fake time INFO tracing_subscriber::fmt::format::test: hello`\n`";
2022	test_ansi(`false`, expected, crate::fmt::Subscriber::builder());
2023	}
2024
2025	#[cfg(not(feature = "ansi"))]
2026	#[test]
2027	fn without_ansi() {
2028	let expected = "fake time INFO tracing_subscriber::fmt::format::test: hello`\n`";
2029	test_without_ansi(expected, crate::fmt::Subscriber::builder())
2030	}
2031
2032	#[test]
2033	fn without_level() {
2034	let expected = "fake time tracing_subscriber::fmt::format::test: hello`\n`";
2035	test_without_level(expected, crate::fmt::Subscriber::builder())
2036	}
2037
2038	#[test]
2039	fn overridden_parents() {
2040	let expected = "fake time span1{span=1}:span2{span=2}: tracing_subscriber::fmt::format::test: hello`\n`";
2041	test_overridden_parents(expected, crate::fmt::Subscriber::builder())
2042	}
2043
2044	#[test]
2045	fn overridden_parents_in_scope() {
2046	test_overridden_parents_in_scope(
2047	"fake time span3{span=3}: tracing_subscriber::fmt::format::test: hello`\n`",
2048	"fake time span1{span=1}:span2{span=2}: tracing_subscriber::fmt::format::test: hello`\n`",
2049	crate::fmt::Subscriber::builder(),
2050	)
2051	}
2052	}
2053
2054	mod compact {
2055	use super::*;
2056
2057	#[cfg(feature = "ansi")]
2058	#[test]
2059	fn with_ansi_true() {
2060	let expected = "`\u{1b}`[2mfake time`\u{1b}`[0m `\u{1b}`[32m INFO`\u{1b}`[0m `\u{1b}`[2mtracing_subscriber::fmt::format::test`\u{1b}`[0m`\u{1b}`[2m:`\u{1b}`[0m hello`\n`";
2061	test_ansi(`true`, expected, crate::fmt::Subscriber::builder().compact())
2062	}
2063
2064	#[cfg(feature = "ansi")]
2065	#[test]
2066	fn with_ansi_false() {
2067	let expected = "fake time INFO tracing_subscriber::fmt::format::test: hello`\n`";
2068	test_ansi(`false`, expected, crate::fmt::Subscriber::builder().compact());
2069	}
2070
2071	#[cfg(not(feature = "ansi"))]
2072	#[test]
2073	fn without_ansi() {
2074	let expected = "fake time INFO tracing_subscriber::fmt::format::test: hello`\n`";
2075	test_without_ansi(expected, crate::fmt::Subscriber::builder().compact())
2076	}
2077
2078	#[test]
2079	fn without_level() {
2080	let expected = "fake time tracing_subscriber::fmt::format::test: hello`\n`";
2081	test_without_level(expected, crate::fmt::Subscriber::builder().compact());
2082	}
2083
2084	#[test]
2085	fn overridden_parents() {
2086	let expected = "fake time span1:span2: tracing_subscriber::fmt::format::test: hello span=1 span=2`\n`";
2087	test_overridden_parents(expected, crate::fmt::Subscriber::builder().compact())
2088	}
2089
2090	#[test]
2091	fn overridden_parents_in_scope() {
2092	test_overridden_parents_in_scope(
2093	"fake time span3: tracing_subscriber::fmt::format::test: hello span=3`\n`",
2094	"fake time span1:span2: tracing_subscriber::fmt::format::test: hello span=1 span=2`\n`",
2095	crate::fmt::Subscriber::builder().compact(),
2096	)
2097	}
2098	}
2099
2100	mod pretty {
2101	use super::*;
2102
2103	#[test]
2104	fn pretty_default() {
2105	let make_writer = MockMakeWriter::default();
2106	let subscriber = crate::fmt::Subscriber::builder()
2107	.pretty()
2108	.with_writer(make_writer.clone())
2109	.with_ansi(`false`)
2110	.with_timer(MockTime);
2111	let expected = format!(
2112	" fake time INFO tracing_subscriber::fmt::format::test: hello`\n` at {}:NUMERIC`\n\n`",
2113	file!()
2114	);
2115
2116	assert_info_hello_ignore_numeric(subscriber, make_writer, &expected)
2117	}
2118	}
2119
2120	#[test]
2121	fn format_nanos() {
2122	fn fmt(t: u64) -> String {
2123	TimingDisplay(t).to_string()
2124	}
2125
2126	assert_eq!(fmt(`1`), "1.00ns");
2127	assert_eq!(fmt(`12`), "12.0ns");
2128	assert_eq!(fmt(`123`), "123ns");
2129	assert_eq!(fmt(`1234`), "1.23µs");
2130	assert_eq!(fmt(`12345`), "12.3µs");
2131	assert_eq!(fmt(`123456`), "123µs");
2132	assert_eq!(fmt(`1234567`), "1.23ms");
2133	assert_eq!(fmt(`12345678`), "12.3ms");
2134	assert_eq!(fmt(`123456789`), "123ms");
2135	assert_eq!(fmt(`1234567890`), "1.23s");
2136	assert_eq!(fmt(`12345678901`), "12.3s");
2137	assert_eq!(fmt(`123456789012`), "123s");
2138	assert_eq!(fmt(`1234567890123`), "1235s");
2139	}
2140
2141	#[test]
2142	fn fmt_span_combinations() {
2143	let f = FmtSpan::NONE;
2144	assert!(!f.contains(FmtSpan::NEW));
2145	assert!(!f.contains(FmtSpan::ENTER));
2146	assert!(!f.contains(FmtSpan::EXIT));
2147	assert!(!f.contains(FmtSpan::CLOSE));
2148
2149	let f = FmtSpan::ACTIVE;
2150	assert!(!f.contains(FmtSpan::NEW));
2151	assert!(f.contains(FmtSpan::ENTER));
2152	assert!(f.contains(FmtSpan::EXIT));
2153	assert!(!f.contains(FmtSpan::CLOSE));
2154
2155	let f = FmtSpan::FULL;
2156	assert!(f.contains(FmtSpan::NEW));
2157	assert!(f.contains(FmtSpan::ENTER));
2158	assert!(f.contains(FmtSpan::EXIT));
2159	assert!(f.contains(FmtSpan::CLOSE));
2160
2161	let f = FmtSpan::NEW \| FmtSpan::CLOSE;
2162	assert!(f.contains(FmtSpan::NEW));
2163	assert!(!f.contains(FmtSpan::ENTER));
2164	assert!(!f.contains(FmtSpan::EXIT));
2165	assert!(f.contains(FmtSpan::CLOSE));
2166	}
2167
2168	/// Returns the test's module path.
2169	fn current_path() -> String {
2170	Path::new("tracing-subscriber")
2171	.join("src")
2172	.join("fmt")
2173	.join("format")
2174	.join("mod.rs")
2175	.to_str()
2176	.expect("path must not contain invalid unicode")
2177	.to_owned()
2178	}
2179	}
2180