logo
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
use super::*;
use crate::{
    field::{VisitFmt, VisitOutput},
    fmt::fmt_layer::{FmtContext, FormattedFields},
    registry::LookupSpan,
};

use std::fmt::{self, Write};
use tracing_core::{
    field::{self, Field},
    Event, Level, Subscriber,
};

#[cfg(feature = "tracing-log")]
use tracing_log::NormalizeEvent;

use ansi_term::{Colour, Style};

/// An excessively pretty, human-readable event formatter.
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Pretty {
    display_location: bool,
}

/// The [visitor] produced by [`Pretty`]'s [`MakeVisitor`] implementation.
///
/// [visitor]: ../../field/trait.Visit.html
/// [`DefaultFields`]: struct.DefaultFields.html
/// [`MakeVisitor`]: ../../field/trait.MakeVisitor.html
pub struct PrettyVisitor<'a> {
    writer: &'a mut dyn Write,
    is_empty: bool,
    ansi: bool,
    style: Style,
    result: fmt::Result,
}

/// An excessively pretty, human-readable [`MakeVisitor`] implementation.
///
/// [`MakeVisitor`]: crate::field::MakeVisitor
#[derive(Debug)]
pub struct PrettyFields {
    ansi: bool,
}

// === impl Pretty ===

impl Default for Pretty {
    fn default() -> Self {
        Self {
            display_location: true,
        }
    }
}

impl Pretty {
    fn style_for(level: &Level) -> Style {
        match *level {
            Level::TRACE => Style::new().fg(Colour::Purple),
            Level::DEBUG => Style::new().fg(Colour::Blue),
            Level::INFO => Style::new().fg(Colour::Green),
            Level::WARN => Style::new().fg(Colour::Yellow),
            Level::ERROR => Style::new().fg(Colour::Red),
        }
    }

    /// Sets whether the event's source code location is displayed.
    ///
    /// This defaults to `true`.
    pub fn with_source_location(self, display_location: bool) -> Self {
        Self {
            display_location,
            ..self
        }
    }
}

impl<T> Format<Pretty, T> {
    /// Sets whether or not the source code location from which an event
    /// originated is displayed.
    ///
    /// This defaults to `true`.
    pub fn with_source_location(mut self, display_location: bool) -> Self {
        self.format = self.format.with_source_location(display_location);
        self
    }
}

impl<C, N, T> FormatEvent<C, N> for Format<Pretty, T>
where
    C: Subscriber + for<'a> LookupSpan<'a>,
    N: for<'a> FormatFields<'a> + 'static,
    T: FormatTime,
{
    fn format_event(
        &self,
        ctx: &FmtContext<'_, C, N>,
        writer: &mut dyn fmt::Write,
        event: &Event<'_>,
    ) -> fmt::Result {
        #[cfg(feature = "tracing-log")]
        let normalized_meta = event.normalized_metadata();
        #[cfg(feature = "tracing-log")]
        let meta = normalized_meta.as_ref().unwrap_or_else(|| event.metadata());
        #[cfg(not(feature = "tracing-log"))]
        let meta = event.metadata();
        write!(writer, "  ")?;

        self.format_timestamp(writer)?;

        let style = if self.display_level && self.ansi {
            Pretty::style_for(meta.level())
        } else {
            Style::new()
        };

        if self.display_level {
            write!(writer, "{}", super::FmtLevel::new(meta.level(), self.ansi))?;
        }

        if self.display_target {
            let target_style = if self.ansi { style.bold() } else { style };
            write!(
                writer,
                "{}{}{}: ",
                target_style.prefix(),
                meta.target(),
                target_style.infix(style)
            )?;
        }
        let mut v = PrettyVisitor::new(writer, true)
            .with_style(style)
            .with_ansi(self.ansi);
        event.record(&mut v);
        v.finish()?;
        writer.write_char('\n')?;

        let dimmed = if self.ansi {
            Style::new().dimmed().italic()
        } else {
            Style::new()
        };
        let thread = self.display_thread_name || self.display_thread_id;
        if let (true, Some(file), Some(line)) =
            (self.format.display_location, meta.file(), meta.line())
        {
            write!(
                writer,
                "    {} {}:{}{}",
                dimmed.paint("at"),
                file,
                line,
                dimmed.paint(if thread { " " } else { "\n" })
            )?;
        } else if thread {
            write!(writer, "    ")?;
        }

        if thread {
            write!(writer, "{} ", dimmed.paint("on"))?;
            let thread = std::thread::current();
            if self.display_thread_name {
                if let Some(name) = thread.name() {
                    write!(writer, "{}", name)?;
                    if self.display_thread_id {
                        write!(writer, " ({:?})", thread.id())?;
                    }
                } else if !self.display_thread_id {
                    write!(writer, " {:?}", thread.id())?;
                }
            } else if self.display_thread_id {
                write!(writer, " {:?}", thread.id())?;
            }
            writer.write_char('\n')?;
        }

        let bold = if self.ansi {
            Style::new().bold()
        } else {
            Style::new()
        };
        let span = event
            .parent()
            .and_then(|id| ctx.span(&id))
            .or_else(|| ctx.lookup_current());

        let scope = span.into_iter().flat_map(|span| span.scope());

        for span in scope {
            let meta = span.metadata();
            if self.display_target {
                write!(
                    writer,
                    "    {} {}::{}",
                    dimmed.paint("in"),
                    meta.target(),
                    bold.paint(meta.name()),
                )?;
            } else {
                write!(
                    writer,
                    "    {} {}",
                    dimmed.paint("in"),
                    bold.paint(meta.name()),
                )?;
            }

            let ext = span.extensions();
            let fields = &ext
                .get::<FormattedFields<N>>()
                .expect("Unable to find FormattedFields in extensions; this is a bug");
            if !fields.is_empty() {
                write!(writer, " {} {}", dimmed.paint("with"), fields)?;
            }
            writer.write_char('\n')?;
        }

        writer.write_char('\n')
    }
}

impl<'writer> FormatFields<'writer> for Pretty {
    fn format_fields<R: RecordFields>(
        &self,
        writer: &'writer mut dyn fmt::Write,
        fields: R,
    ) -> fmt::Result {
        let mut v = PrettyVisitor::new(writer, true);
        fields.record(&mut v);
        v.finish()
    }

    fn add_fields(&self, current: &'writer mut String, fields: &span::Record<'_>) -> fmt::Result {
        let empty = current.is_empty();
        let mut v = PrettyVisitor::new(current, empty);
        fields.record(&mut v);
        v.finish()
    }
}

// === impl PrettyFields ===

impl Default for PrettyFields {
    fn default() -> Self {
        Self::new()
    }
}

impl PrettyFields {
    /// Returns a new default [`PrettyFields`] implementation.
    pub fn new() -> Self {
        Self { ansi: true }
    }

    /// Enable ANSI encoding for formatted fields.
    pub fn with_ansi(self, ansi: bool) -> Self {
        Self { ansi, ..self }
    }
}

impl<'a> MakeVisitor<&'a mut dyn Write> for PrettyFields {
    type Visitor = PrettyVisitor<'a>;

    #[inline]
    fn make_visitor(&self, target: &'a mut dyn Write) -> Self::Visitor {
        PrettyVisitor::new(target, true).with_ansi(self.ansi)
    }
}

// === impl PrettyVisitor ===

impl<'a> PrettyVisitor<'a> {
    /// Returns a new default visitor that formats to the provided `writer`.
    ///
    /// # Arguments
    /// - `writer`: the writer to format to.
    /// - `is_empty`: whether or not any fields have been previously written to
    ///   that writer.
    pub fn new(writer: &'a mut dyn Write, is_empty: bool) -> Self {
        Self {
            writer,
            is_empty,
            ansi: true,
            style: Style::default(),
            result: Ok(()),
        }
    }

    pub(crate) fn with_style(self, style: Style) -> Self {
        Self { style, ..self }
    }

    pub(crate) fn with_ansi(self, ansi: bool) -> Self {
        Self { ansi, ..self }
    }

    fn write_padded(&mut self, value: &impl fmt::Debug) {
        let padding = if self.is_empty {
            self.is_empty = false;
            ""
        } else {
            ", "
        };
        self.result = write!(self.writer, "{}{:?}", padding, value);
    }

    fn bold(&self) -> Style {
        if self.ansi {
            self.style.bold()
        } else {
            Style::new()
        }
    }
}

impl<'a> field::Visit for PrettyVisitor<'a> {
    fn record_str(&mut self, field: &Field, value: &str) {
        if self.result.is_err() {
            return;
        }

        if field.name() == "message" {
            self.record_debug(field, &format_args!("{}", value))
        } else {
            self.record_debug(field, &value)
        }
    }

    fn record_error(&mut self, field: &Field, value: &(dyn std::error::Error + 'static)) {
        if let Some(source) = value.source() {
            let bold = self.bold();
            self.record_debug(
                field,
                &format_args!(
                    "{}, {}{}.source{}: {}",
                    value,
                    bold.prefix(),
                    field,
                    bold.infix(self.style),
                    source,
                ),
            )
        } else {
            self.record_debug(field, &format_args!("{}", value))
        }
    }

    fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
        if self.result.is_err() {
            return;
        }
        let bold = self.bold();
        match field.name() {
            "message" => self.write_padded(&format_args!("{}{:?}", self.style.prefix(), value,)),
            // Skip fields that are actually log metadata that have already been handled
            #[cfg(feature = "tracing-log")]
            name if name.starts_with("log.") => self.result = Ok(()),
            name if name.starts_with("r#") => self.write_padded(&format_args!(
                "{}{}{}: {:?}",
                bold.prefix(),
                &name[2..],
                bold.infix(self.style),
                value
            )),
            name => self.write_padded(&format_args!(
                "{}{}{}: {:?}",
                bold.prefix(),
                name,
                bold.infix(self.style),
                value
            )),
        };
    }
}

impl<'a> VisitOutput<fmt::Result> for PrettyVisitor<'a> {
    fn finish(self) -> fmt::Result {
        write!(self.writer, "{}", self.style.suffix())?;
        self.result
    }
}

impl<'a> VisitFmt for PrettyVisitor<'a> {
    fn writer(&mut self) -> &mut dyn fmt::Write {
        self.writer
    }
}

impl<'a> fmt::Debug for PrettyVisitor<'a> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("PrettyVisitor")
            .field("writer", &format_args!("<dyn fmt::Write>"))
            .field("is_empty", &self.is_empty)
            .field("result", &self.result)
            .field("style", &self.style)
            .field("ansi", &self.ansi)
            .finish()
    }
}